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Brown & Sharp Surface Grinder

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Robo_Pi

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I found this Brown and Sharp surface grinder for sale for $218. Whadda think?

287383

Comes complete with a mag chuck!

287384

A 440 volt 3 phase motor:

287385

And the motor controller electronics:

287386

Ok, I already know this is going to suck all the nay-sayers out of the woodwork. But let's think about this in more detail.

First off, this thing weighs enough that if I took it straight to the metal scrap yard I'd probably get a full refund for what I paid for it. (worse case scenario)

But let's consider the fun we might be able to have with this thing.

To begin with the electronic motor controller relays look to be in pretty good shape considering how badly rusted the rest of the machine is. Let's pretend that the motor actually runs and doesn't sound too bad after a bit of oiling. Let's then clean up the motor and electronic controller cabinet to make them look pretty with a little bit of paint. Then put those items on Craigslist. Assuming the motor actually runs and isn't too noisy how much do you think we could recover by selling the 440 volt motor and control?

On a personal note, if the motor is completely shot, it goes to the scrap metal yard and I could use those nice big relays. Large relays like that aren't cheap! :grin:

Ok, now with the motor out of the way, what about the rest of the machine? I've been looking for a mag chuck restoration project so there's my mag chuck to play with. Again, no biggie if it turns out to be impossible to use. Scrap yard saves the day again.

Finally we're down to the actual machine. Is is possible to put this thing back into some sort of usable shape? We can't really answer that question without getting our hands dirty and giving it a shot. I'm willing to bet that this thing could be freed up enough to take it apart. Then go bananas with an angle grinder and wire brush to clean up all the ways. Clean up the rest of the outside of the machine. Paint it - reassemble everything. Put a 110 motor on it. And use it as a tool grinder. :grin:

Sounds good to me. Where are you going to get a nice tool grinder for $218 minus whatever you got for the motor and controller. Plus, there's always the wild chance that the mag chuck might actually turn out to be rebuildable. I realize it looks pretty bad, but I've seen some this bad being rebuilt before, so it's not necessarily an impossibility.

Think like a hobbyist. It wouldn't be worth the time as a business. But for a hobbyist? It sure would make a nifty tool bit grinder. :grin:

That's assuming the table can be brought back to life. I haven't seen the machine in person, so I don't know whether the table is free to move or rusted solid in place. It's impossible to tell from the photo. Sometimes things can look worse than they truly are. I'm betting the table can be freed up, even if it is frozen in place. Don't they have adjustable gibs? If so, then it should definitely be possible to free it up if frozen in place.

I wanna play with some junk! Would be nice to get it for free of course. But $218 is basically scrap metal prices. So it basically already is free from that perspective.

If nothing else it will serve as a conversation piece on a hobby forum. And I didn't even need to actually buy it to use it for this. :grin big:
 

f350ca

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If nothing else, you have a set of castings to machine a grinder from.


Greg
 

JimDawson

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Looks like a project. Should be a fun one. :encourage:
 

Latinrascalrg1

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So long as moving cost are a good deal i think you cant loose at that price even if you would end up parting it out you would end up with a profit even if its not very profitable.
 

Robo_Pi

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What model is it?
287401

So long as moving cost are a good deal i think you cant loose at that price even if you would end up parting it out you would end up with a profit even if its not very profitable.
Well, it's 200 miles from me. But I have a pickup truck and 16' trailer. Although I could probably just pick this up with the pick up alone?

I need to put a new clutch in my truck first though. I'll bet this sweet baby will be gone by the time I replace the clutch. :D

By the way, they actually have a far nicer one for only $235. No mag chuck, but overall it appears to be in pretty good shape.

287402

This one is a Taft-Pierce. This would definitely by my first choice or these two. :grin:

I really just posted the Brown & Sharp for forum chat.

They also have some even better ones for slightly more money like $399. But that's starting to get to be more than I want to spend on a SG.

I'm just looking for a toy to make into a tool bit grinder. Might use it for some other stuff too. But the closer I can get to $200 or less the better. Like I say, much less and we're getting beneath the value of scraping it at a metal yard. I don't think they'll bother selling one for less than scrap metal prices. They can scrap it themselves at that point.
 

Bob Korves

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The current cast iron scrap price nation wide is about $0.16/lb. ($300/ton), delivered to the scrapper. That is for cast iron ready to melt, not assembled machines that also contain steel, motors, and other stuff that all has to be broken up and segregated.

I thought it looked like a Micromaster. It must be an earlier example of that model. They are highly regarded grinders, but that one looks like it may have been sitting around out in the weather for a long time, and so might require significant work before it returns to it's former glory.

The Taft Pierce is also a very highly regarded surface grinder. That one also will need a lot of work to get it in fine shape again.
 

Technical Ted

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When I bought my B&S SG (for $200) I couldn't see it running first. My biggest concern was the spindle condition since replacing the bearings can be quite expensive. If you can see them running, do it and check the spindle bearings. If they can't run it, turn it over by hand and see if you can feel any rough spots. I was lucky and found a diamond in the rough... well, maybe not a diamond, but good enough for my use for $200!

Another expense will be adapters for mounting the grinding wheels. Try to get some with your deal. The mag chuck is a big plus as well. It's easy to spend more money after the initial cost of the machine just to get it running and fully operational.

Ted
 

Robo_Pi

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The current cast iron scrap price nation wide is about $0.16/lb. ($300/ton), delivered to the scrapper. That is for cast iron ready to melt, not assembled machines that also contain steel, motors, and other stuff that all has to be broken up and segregated.
Agreed. Taking it straight to the scrap yard without touching it would lose. At my scrap yard breaking things up to less than 3 foot lenghts basically doubles the scrap price. But yeah, buying it looking to make money scrapping it wouldn't be a good idea. It's just a way to recover some of the cost if it turns out to be totally unusable.

I thought it looked like a Micromaster. It must be an earlier example of that model. They are highly regarded grinders, but that one looks like it may have been sitting around out in the weather for a long time, and so might require significant work before it returns to it's former glory.

The Taft Pierce is also a very highly regarded surface grinder. That one also will need a lot of work to get it in fine shape again.
Again agreed. I'm looking to gain some initial experience at machine rebuilding. Obviously, (or may not so obviously) I'm not going to shoot for an immaculate restoration on my first rebuild project. The idea is to just gain some experience and have fun. I might try to get into machine restoration at some future date on a more serious level, but if I do that I'll start off with better starting projects.

Right now the goal is to gain some experience, have some fun, and maybe end up with a usable grinder for odd jobs. Not expecting to be able to grind large surfaces to within a few tenths. As a tool bit sharpener it wouldn't need to be very accurate at all. On a 1/2" tool bit we're only talking about being accurate over 1/2". That should be doable. :grin:

One of the reasons I'm thinking about this is because I just ground a 1/2" threading tool bit using a home made 30 degree sled on a bench grinder. I actually got the job done but it took forever. And it was also difficult to get it just right. I actually had to tweek it by eye freehand at the end to get it to match up with the thread I want to cut. I haven't cut the thread yet, I hope it works!

But the whole time I was cutting it I was thinking how easy and accurate this could have been if I had an old junk surface grinder. Overkill I know, but still, much easier. :grin:

So if I can get one of these low-cost starter-project surface grinders to play with, I'll not only have fun rebuilding it and learning a lot about machine restoration, but I'll end up with a lazy and accurate way to make fancy tool cutters. I know it's extreme overkill, but that's ok. It's still fun.
 

Robo_Pi

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When I bought my B&S SG (for $200) I couldn't see it running first. My biggest concern was the spindle condition since replacing the bearings can be quite expensive. If you can see them running, do it and check the spindle bearings. If they can't run it, turn it over by hand and see if you can feel any rough spots. I was lucky and found a diamond in the rough... well, maybe not a diamond, but good enough for my use for $200!
Sounds great! I wonder though if it would be a very good idea to turn it on without taking it apart to make sure the bearings are well greased or oiled (whatever they use). Turning it on to test it could potentially damage good bearings that might have otherwise been salvageable. I've ruined dry bearings that way before so I'm very leary about turning things on before I inspect the bearings up-close and personal.

Another expense will be adapters for mounting the grinding wheels. Try to get some with your deal. The mag chuck is a big plus as well. It's easy to spend more money after the initial cost of the machine just to get it running and fully operational.
I doubt that they would be willing to throw anything in at this price. They actually have this "marked down" from $312. A price I definitely would not give them for this machine. But $218,? Maybe. Although I would definitely grab the Taft-Pierce for $235 first.
 

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If you want to play, and the price is not a problem, go for it
 

Bob Korves

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Right now the goal is to gain some experience, have some fun, and maybe end up with a usable grinder for odd jobs.
That makes good sense.

As a tool bit sharpener it wouldn't need to be very accurate at all. On a 1/2" tool bit we're only talking about being accurate over 1/2". That should be doable.
True, and a good use for a surface grinder, but it does take time to set up for compound angles, and is much easier with an magnetic angle $ine plate or other universal type fixture.

I wonder though if it would be a very good idea to turn it on without taking it apart to make sure the bearings are well greased or oiled (whatever they use). Turning it on to test it could potentially damage good bearings that might have otherwise been salvageable.
Correct. Don't try to run either of those old machines that have been sitting around. Turn the bearings slowly by hand, but don't force them. Feel for roughness and for play in both directions. A bad spindle is usually a deal breaker to a hobbyist looking at an old surface grinder.

One of the reasons I'm thinking about this is because I just ground a 1/2" threading tool bit using a home made 30 degree sled on a bench grinder. I actually got the job done but it took forever.
Surface grinders have all kinds of usefulness with small quick grinding jobs. Even making a washer or nut thinner. The mag chuck is most of the magic. It sounds like you have your head in the right place to look at them and maybe pick one up. Just trying to make sure you see reality reasonably clearly. I should talk, I bought a 1946/1947 B&S 2L with a known bad plain bearing spindle which was disassembled, and the rest of the machine pretty much an unknown. It works well now... And I bought it from benmychree, who is a straight up man.

.
 

Robo_Pi

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Thanks for the insightful comments Bob,

Here's some more questions I'd really appreciate your wisdom on.

They have two more surface grinders close to my price range. They are asking $299 each for these.

I'll ask questions following these photos.

First let me say that the original grinder I posted, (the rusty Brown and Sharp) had the motor located on the lower back and was apparently driven by a belt?

I just realized the Taft-Pierce has its motor mounted directly on the grinding wheel shaft behind the machine.
287420


They also have this Do All grinder for $299 No mag chuck here either.
287421

I just noticed the Do All also has the motor mounted directly on the grind wheel shaft

287422


Finally they have this Covel grinder also for $299 This one has a mag chuck on it.
287423

But notice the back of the Covel. No motor sticking out. Is the motor in the base?
287424


These all have 440 3-phase motors. So I'm guessing that I'm going to need to replace the motor with a 120v or 240v standard residence electric. For my use I would actually prefer to run it on 120 if possible.

In any case. I wonder which motor style might be the easiest to replace?

I kind of like the Covel. Where is the motor on the Covel? Can't tell by the photo.

I might be willing to go as much as $300 for a potentially better starting project. That would be about my upper limit for a surface grinder right now. I like the style of the Covel. It kind of looks like a vertical mill the way the handles are laid out. I like old-fashioned looking stuff. :grin:

Anyway I just thought I'd toss this out here. I'll most likely need to replace the motor with something that can handle my resident electric service. So how the motor mounts might be something worth taking into consideration. I also like the fact that on the Covel there' s no motor sticking out the back of it making it possible to push up closer to a wall. The ones with the motor sticking out the back are going to take up a larger footprint in the shop. Although even though the Covel saves back space, it's got those big handwheels sticking out on the front. I'll probably be banging into those all the time. :grin:

Always trade-offs to be consider.
 

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Even if these are 'practice' rebuilds, $200-$300 is a small price to pay for the entertainment! I paid over $2200 for mine and I'm still rebuilding it! 14 months on....
 

Robo_Pi

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Even if these are 'practice' rebuilds, $200-$300 is a small price to pay for the entertainment! I paid over $2200 for mine and I'm still rebuilding it! 14 months on....
My thinking as well. Besides I really don't need a surface grinder. I just want to play around with one.

My "Big Plan". Is to also get a nice lathe and vertical milling machine to rebuild as well. But I'm willing to pay about a grand a piece for those. My total "allowance" for play is $2500. So we'll see what happens.

People might say, "Why not just wait until you're ready to buy?" But actually posting all these potential finds and asking questions about them helps me to learn a bunch of stuff in the interim. Just like with these grinders. I only just now realized that they all have motors mounted differently, so that might be something useful to consider in the long haul.

I'm probably not going to actually buy anything until mid summer. In fact, these particular machines will most likely be long gone by then and I'll have to choose from whatever new has come in. They already sold two lathes and a milling machine I had my eye on. I'm currently looking at a really nice lathe for $999, but I'm sure it will be long gone by the time I'm ready to buy. None the less I actually learned a lot just buy posting about those potential purchases. So I hope it's ok to keep asking questions. :grin:

When I finally do pick up the real thing I'll have a much better idea what I'm getting into.
 

Asm109

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I would plan on running 220V single phase to the grinder and then buying a VFD to run the motor.
Assuming the 440V motor is running and has not had the smoke let out.
 

Bob Korves

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Thanks for the insightful comments Bob,

Here's some more questions I'd really appreciate your wisdom on.

They have two more surface grinders close to my price range. They are asking $299 each for these.

I'll ask questions following these photos.

First let me say that the original grinder I posted, (the rusty Brown and Sharp) had the motor located on the lower back and was apparently driven by a belt?

I just realized the Taft-Pierce has its motor mounted directly on the grinding wheel shaft behind the machine.
View attachment 287420


They also have this Do All grinder for $299 No mag chuck here either.
View attachment 287421

I just noticed the Do All also has the motor mounted directly on the grind wheel shaft

View attachment 287422


Finally they have this Covel grinder also for $299 This one has a mag chuck on it.
View attachment 287423

But notice the back of the Covel. No motor sticking out. Is the motor in the base?
View attachment 287424


These all have 440 3-phase motors. So I'm guessing that I'm going to need to replace the motor with a 120v or 240v standard residence electric. For my use I would actually prefer to run it on 120 if possible.

In any case. I wonder which motor style might be the easiest to replace?

I kind of like the Covel. Where is the motor on the Covel? Can't tell by the photo.

I might be willing to go as much as $300 for a potentially better starting project. That would be about my upper limit for a surface grinder right now. I like the style of the Covel. It kind of looks like a vertical mill the way the handles are laid out. I like old-fashioned looking stuff. :grin:

Anyway I just thought I'd toss this out here. I'll most likely need to replace the motor with something that can handle my resident electric service. So how the motor mounts might be something worth taking into consideration. I also like the fact that on the Covel there' s no motor sticking out the back of it making it possible to push up closer to a wall. The ones with the motor sticking out the back are going to take up a larger footprint in the shop. Although even though the Covel saves back space, it's got those big handwheels sticking out on the front. I'll probably be banging into those all the time. :grin:

Always trade-offs to be consider.
Check to see for sure if the motors are 440v only. Often they will be 220/440v. Look on the motor tags. 3 phase runs smoother than single phase does, and a VFD makes it easy to hook up. The motors directly behind the spindle are a more recent idea. They eliminate belts, which take a lot of hardware to make them work ,and the spindle/motor assembly is also more easily and simply able to go up and down while they are running. Belts introduce some mechanical noise into the spindle, which seems not to hurt much, but the direct drive spindles, with just spider shaped rubber Lovejoy couplings, are inherently smooth and simple designs. After 20 years, the coupling gets loose and you change the Lovejoy coupling, easy to find at any motor shop or Grainger for a few dollars. Easy to do, reliable, simple. My old 1940's B&S 2L grinder has a 126" long, 2" wide reinforced rubber flat belt than runs over 4 idler pulleys and the motor and spindle pulleys. It also has a heavy counterweight arm on one of those pulleys. If the belt falls off a pulley or breaks, the expensive belt is likely to be ruined, and all those components can add noise to the spindle that is supposed to run dead smooth. In reality, the heavy spindle on my grinder that runs in stout bronze bearing boxes seems to run dead smooth, so maybe with all the inertia and the reinforced rubber belt it runs smooth. I would not be surprised if B&S put a lot of effort in the design to make it all run smoothly, cuz' it still does more than 70 years later. But really, to me the newer direct drive style spindles make a lot more sense, and must be both more robust and hugely less expensive to design, build, and maintain. Beyond the spindle belt and hardware, my grinder also has a 1x36(?) leather flat belt that runs the power feeds and the table traverse, through a whole mass of shafts, gears, and other mechanical stuff that keep the heavy table moving smoothly from end to end, absorbing energy in an incredible spring contraption and then feeding it back in the other direction, and the other belt also moving the table over in adjustable increments to the front or to the rear of the saddle for cross feeds. All have adjustable stops and adjustable step overs in either direction. It takes ~10 minutes to lube everything before starting the motor running. To make a machine like that today would be prohibitively expensive. But, it still soldiers on, in decent condition, everything works, 70 years later.

The Covel you posted the picture of is a very old design, which says nothing about it's quality. It is all about the execution when it was designed and made. Any of these old machines need to be checked out very carefully before buying them. A lot of the parts are special made, custom stuff, and parts are not available for them except if you get lucky and find a used part off another old machine. Think seriously for a while about things you will have to repair or make from scratch. Too much of that or too difficult and the project often languishes.

Bottom line, all those styles work fine if they are well designed and taken care of. Don't be in a big hurry to say yes to one, check it out carefully, and ask yourself if it looks like something you really want to get into a long term relationship with...
 

C-Bag

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My thinking as well. Besides I really don't need a surface grinder. I just want to play around with one.

My "Big Plan". Is to also get a nice lathe and vertical milling machine to rebuild as well. But I'm willing to pay about a grand a piece for those. My total "allowance" for play is $2500. So we'll see what happens.

People might say, "Why not just wait until you're ready to buy?" But actually posting all these potential finds and asking questions about them helps me to learn a bunch of stuff in the interim. Just like with these grinders. I only just now realized that they all have motors mounted differently, so that might be something useful to consider in the long haul.

I'm probably not going to actually buy anything until mid summer. In fact, these particular machines will most likely be long gone by then and I'll have to choose from whatever new has come in. They already sold two lathes and a milling machine I had my eye on. I'm currently looking at a really nice lathe for $999, but I'm sure it will be long gone by the time I'm ready to buy. None the less I actually learned a lot just buy posting about those potential purchases. So I hope it's ok to keep asking questions. :grin:

When I finally do pick up the real thing I'll have a much better idea what I'm getting into.
This is a great place to do your "plan". Sometimes you can follow a thread here and get what you need. Sometimes you just have to jump in like you did. SG's are a very deep subject and my foray into the abyss of gathering intell on them here was very satisfying. But it also made me very cautious as there are very few SG's around here and I've only seen basket cases for $4-500 and never $2-300 like you seem to have endlessly. Sketchy ones start at $1k+ and I'm not sure the more expensive ones don't have problems. Best of luck and good hunting.
 

Robo_Pi

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Check to see for sure if the motors are 440v only. Often they will be 220/440v. Look on the motor tags. 3 phase runs smoother than single phase does, and a VFD makes it easy to hook up. The motors directly behind the spindle are a more recent idea. They eliminate belts, which take a lot of hardware to make them work ,and the spindle/motor assembly is also more easily and simply able to go up and down while they are running. ,...
Thank you very much Bob, for sharing your vast knowledge. You're about to earn this website a donation from me. I have no problem paying for quality information as you have been providing. :grin:

I'm actually pretty heavy into electronics. Only more into the computer end of it, like Arduino and Raspberry Pi. Most of the motors I work with are usually either small PM motors, stepper motors, or servo motors. All usually running on anything from 5 volts to 24 volts. So I have a lot of experience with that sort of thing. But when it comes to large AC motors I really don't have much experience.

If I can use the motors that come on these machines with my current 220v residential service, I'll definitely go with that. I didn't know that 3 phase motors would be compatible with standard residential electric service. So apparently I have a lot to learn about these motors. It appears I'll be dealing with the same motor issues with the lathe and milling machine too. I was thinking that I would need to replace the motors on all of these. I used to have a Bridgeport Mill, and a large South Bend lathe. Both of those ran on regular 110 AC. As far as I can remember that's the way those machines where when I bought them. I don't recall having motor issues with those. But that was quite some time ago.


Bottom line, all those styles work fine if they are well designed and taken care of. Don't be in a big hurry to say yes to one, check it out carefully, and ask yourself if it looks like something you really want to get into a long term relationship with...
I'm in no hurry to actually buy. But I am kind of anxious to learn before I buy. :grin:

I do have one consideration that may come into play. I don't like to drive long distances anymore than I need to. I also don't really feel like driving around picking up three different machines from three different places. The place where I'm finding these machines is 200 miles from me. From what I have seen thus far they seem to have a large overturn in inventory and they appear to have some pretty good prices, at least in terms of what I'm willing to pay.

Ideally I would like to set things up so I can just pick up all three machines in one fell swoop. One trip to rule them all. :grin:

I'm far more picky about the lathe and vertical mill. So when they have a lathe and vertical mill I'm happy with I'll probably just grab whatever cheap surface grinder they happen to have on the floor at that time. Just so I can pick them all up at once and saving having to make another trip. Not to worry about saving money. I just don't like to travel anymore than I need to. So this is something I'm considering.

I might consider something closer if I find something on Craigslist, etc. We'll have to see how things work out.

The other thing nice about buying everything at this one place is that they will load everything on the trailer lickety split. Usually when you buy something heavy from someone on Craigslist you end up spending a day trying to inch the machine up trailer ramps, etc.

Anyway, these may seem like trival concerns. But it's just the way I operate. When I do make this trip I just want to make one trip and come home with all three machines on the trailer. So it's not exactly a matter of impatience. It's just that I don't want to spend all summer going around buying three different machines.

The other thing too, at least with the surface grinder. At the price I'm willing to pay, it's not going to be the end of the world if it turns out to be total junk. As I've already suggested, some money could be recouped by the scrap yard, and selling whatever parts on the machine I might be able to sell.

It's not like I'm paying $2500 for a surface grinder and ending up with absolute junk. That would be major loss.

Losing $300 with some potential recovery via scrap metal and parting it out isn't going to be a life-altering loss. :grin:
 

Robo_Pi

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This is a great place to do your "plan". Sometimes you can follow a thread here and get what you need. Sometimes you just have to jump in like you did. SG's are a very deep subject and my foray into the abyss of gathering intell on them here was very satisfying. But it also made me very cautious as there are very few SG's around here and I've only seen basket cases for $4-500 and never $2-300 like you seem to have endlessly. Sketchy ones start at $1k+ and I'm not sure the more expensive ones don't have problems. Best of luck and good hunting.
Well, I don't know if this is a fluke or what. But this company currently has 4 surface grinders for under $300 if you want to count the rust bucket posted in the OP on that list. And they had a couple more that have already been sold. I don't know if this is a regular thing for them, or if they just happen to have a bunch of junk surface grinders right now. I'm hoping this is a normal situation. But it could be that come summertime they won't have any cheap surface grinders to play with. I just don't know.

Same things goes for the lathes and vertical mills. I've been watching and they just got in, and sold a couple pretty nice lathes and milling machines for under a grand. Again, I don't know if this is business as usual, or if this is just a fluke?

I'm hoping it's business as usual. :grin:

They have a really nice Sebastian lathe for $999 right now. I'd buy that baby if I could. But my truck needs a new clutch. So some other lucky hobbyist is going to end up owning that Sebastian lathe. In fact, I'm willing to bet that it's gone before the end of this week.
 

Janderso

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When I bought my B&S 618 Micromaster, I took an expert with me.
I wanted a surface grinder but was not familiar with the machines.
Take your time and get some help. You will not be sorry.
 

Boswell

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I didn't know that 3 phase motors would be compatible with standard residential electric service.
just so there is no mis-understanding. a 3 phase motor can run on standard residential single phase power WITH the addition of a phase converter. Apparently they are not too expensive or hard to install as I see them mentioned in many threads.
 

Janderso

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I am moving my equipment to a home shop next month.
I chose to go with a Rotary Phase Converter which will give me all the options I need.
I did have a VFD for my Bridgeport at the old house, worked great.
We home shop guys have options and plenty of them.
You do need to open your wallet though :)
 

Bob Korves

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If I can use the motors that come on these machines with my current 220v residential service, I'll definitely go with that. I didn't know that 3 phase motors would be compatible with standard residential electric service. So apparently I have a lot to learn about these motors. It appears I'll be dealing with the same motor issues with the lathe and milling machine too. I was thinking that I would need to replace the motors on all of these. I used to have a Bridgeport Mill, and a large South Bend lathe. Both of those ran on regular 110 AC. As far as I can remember that's the way those machines where when I bought them. I don't recall having motor issues with those. But that was quite some time ago.
It is quite easy to run 3 phase motors off of single phase power. It takes a VFD, variable frequency drive. Units are available to run 220 3hp for under $100. They are not difficult to hook up. The up side is that you also get a "turn the knob" speed (actually output frequency) control and a reversing control as part of the deal, and many more adjustment possibilities. Running a motor with them is simple. The issues come when the machine has more involved wiring, like contactors, multiple motors, magnetic motor starters, etc. A VFD needs to connect directly to the motor, with nothing in between or in parallel. This is not usually a problem for an older surface grinder, but many lathes and quite a few milling machines have far more involved electrics than just an on/off switch. The other issue is that the VFD does not change the voltage, only the a/c frequency. Changing voltage will require a transformer, and they are relatively expensive, bulky, and noisy. They also lose some efficiency. So, find simple machines with a motor that will run on three phase 220 and they will be easy to hook up to a single phase supply using a VFD. They are also often cheaper as well as better, many hobbyists do not want to or think they can mess with 3 phase due to lack of understanding, and the machines are obsolete for commercial work, so they are orphans, unwanted, and therefore sold cheap or scrapped. Which can be good for us, if we get to them before they go to the scrapper.
 

Robo_Pi

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I'll have to look into the VFD. I work with electronics all the time, and I do all my own house wiring, etc. So I have no problem working with electrical components. Since I'm getting at least 3 machines what will most likely have 3 phase motors on them it might do well to go that route. I wonder if I could make the VFD portable and just wheel it around to the machine I want to use at the moment, instead of wiring it into a single machine permanently. I can't imagine why I couldn't do that. One VFD to rule them all. :grin:

I mean it will just be a hobbyist shop, so it's not like I'll need to have all three machines running at the same time. Sorry for being so frugal, but if I can cut the cost by 2/3 why not?
 

Robo_Pi

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When I bought my B&S 618 Micromaster, I took an expert with me.
I wanted a surface grinder but was not familiar with the machines.
Take your time and get some help. You will not be sorry.
If I took an expert with me to look at these $300 surface grinders she would just look at me and say, "You can't be serious".

When your a "bottom feeder" you kind of just need to grab whatever looks like it might work and hope for the best. :grin:

I mean when you stop and think about it all I'm really doing is saving an old junk surface grinder from the scrap yard. If I took an expert with me she would just say, "Let the poor thing rest in peace".
 

Bob Korves

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Moving a VFD often from machine to machine is rarely done. First, you get it all adjusted so they work well together, and when you move it, you will want to do it again for the next machine. If you used good connection hardware to make all the various wires hook up automatically by plugging them in at the next machine, and made them foolproof, it could work, but you would likely not want to change the settings all the time from machine to machine. Accidentally starting the VFD without it properly hooked up to a motor can maybe damage or kill the VFD. They really want to be hard wired from VFD to motor, with no other hardware in between -- "Idiot proof." It is possible to do otherwise, but I do not recommend it...
 

Robo_Pi

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It is possible to do otherwise, but I do not recommend it...
Doing things that aren't recommended is my life story. :grin:

The bulk of my career was in R&D. In the 1970's I worked for a company that designed inertial guidance systems for ballistic missiles. At one point I was working on the motor controllers that go inside military tanks and keep the canon locked onto the target while the tank vehicle itself is bouncing all over the place climbing over ruts or sand dunes. So I have some experience with extreme motor control. Of course those were DC servo motors. I never worked with 3 phase AC motors before. But it can't be that bad.

I look into it. If it's doable I'll do it. If not, I'll just convert the machines over to standard 110/220v motors. I'll do whichever is easiest or the most cost effective for me. Obviously I'll need to do something as it appears that most of these machines are going to have 3 phase motors on them. But that issue will apparently exist for pretty much any machine I get. Unless I get one from Craigslist which will most likely already have a VFD or standard 110/220v motor on it already.

Worse case scenario I can always mount lawnmower engines on them and run them on gasoline. :grin:
 

Dabbler

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Robo_Pi I do move my VFD around from machine to machine, so it can be done - within strict limits... All 3 of my 3 PH motors are 2HP, and all are within 15% of the same rated current - yes, not all 2 HP motors are alike. If your rated current is out by more than that, expect serious problems, like losing your VFD... (In my case 2 of the motors are rated at the SAME current and one is off by 6%)

- you can reprogram the VFD for any running current, but it is a pain, and you'll forget, and then the trouble starts....

My VFD plugs into the wall using a 4 pole 30A twistloc (or Hubbel, if you like), and the motor plugs into the VFD using a 20 Amp 4 pole twistloc.

I hope this helps. [Yes, I am too cheap to buy another VFD!]
 
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