Trying to size a first mill

[krby]

Apologies if this has been covered already. If so, point me to the thread and I'll delete this one.

I'm interested in buying a bench top mill. I'm trying to figure out the tradeoffs (besides workpiece size) between something like a Sherline 12"/14"/18" mill, an LMS 3990/6500/6700, or Precision Matthews PM-25 or PM-728VT. I can read the specs, I get that heavier and more rigid is better. I guess what I'm really wondering, is could I "go cheap" on smaller Sherline machine to get started, and if I get hooked in this hobby I'd have more experience and know more about what I wanted in a next machine. This happened to me in 3D printing. I bought my first, built my second.

So, what couldn't I do on a Sherline? From other posts, it looks like it will handle aluminum and mild steel, which feels like it'll be fine for But if I had something harder occasionally, could the smaller machine handle it as long as I was patient and took light cuts? I also assume that I'm giving up some precision, but my guess is that since I'm learning most problems will be my fault. Is it possible to expect 0.001" precision once I build the skill and I'm careful?

I guess I'd might end up replacing tooling if moving from a Sherline-sized machine to PM-sized machine? But a lot of the related tools like parallels, indicators, gauges, would be the same.

 

[Asm109]

Sherlines are well made and precise. They can work t the precision number you mentioned, operator skill factored in of course.
The limits are power and rigidity which translates to small cuts and low material removal rates. Sherline sponsors a precision model museum where a lot of the workpieces were made on sherline equipment. No lack of amazing things there. There should be a link from the sherline website.

 

[Chipper5783]

Avoid the really cheap. If you get something that does not perform well, then it is an exercise in frustration - and you may not stick with it. I suggest going for a good bit heavier, more rigid and have a better start to the hobby. If you end up not sticking with it - the better machine will have a better resale value.

Don't go cheap.

 

[krby]

Avoid the really cheap. If you get something that does not perform well, then it is an exercise in frustration - and you may not stick with it. I suggest going for a good bit heavier, more rigid and have a better start to the hobby. If you end up not sticking with it - the better machine will have a better resale value.

Don't go cheap.

Ok, so is Sherline something you consider "really cheap"? I've done some initial research that led me to Sherline, LMS, and PM as reputable brands in these sizes. I was pretty settles on the PM-25 or their newer 728, and just figuring out how to justify the cost. But over the holidays, my uncle suggested I look at something like his Emco Unimat 3, which got me thinking that a smaller machine would be good enough place to get started, take less space, and take less initial budget.

 

[Aukai]

It took me 3-4 years to find out I'm hooked. I started with a Grizzly G0755 first, then found this site, and went with a Precision Matthews 1228 lathe. By year 5 is when I knew I was going to upgrade my machines, both sold quickly, and now I have an ACRA LCM50 9 x 50 mill, and a PM 1340GT lathe. I'm glad I learned on my first machines, but it did cost me more in the long run. We have ebay, and Craig's listing on this site, there are some real good deals once in a while.

 

[MrWhoopee]

Regardless of what size machine you decide on, it will be too small, too light, too quickly. Don't start out that way.

 

[davidpbest]

It took me 3-4 years to find out I'm hooked. I started with a Grizzly G0755 first, then found this site, and went with a Precision Matthews 1228 lathe. By year 5 is when I knew I was going to upgrade my machines, both sold quickly, and now I have an ACRA LCM50 9 x 50 mill, and a PM 1340GT lathe. I'm glad I learned on my first machines, but it did cost me more in the long run. We have ebay, and Craig's listing on this site, there are some real good deals once in a while.

I agree with @Aukai . Cry once. I'm on my 3rd lathe and 2nd mill now. Maybe the two attachments will help.

 

[matthewsx]

Do you have a lathe yet?

If not I'd suggest finding a good used lathe to start with, there are many things you can do on a lathe that can also be done on a mill but not as much the other way.

I see you're in Los Altos, I grew up in Cupertino and live over the hill in Santa Cruz now. Decent used machines do come up around here but you need to know what you're looking for and be ready to act when they do.

Sherline makes good machines for their size, many folks on here still have their original Sherline machines even after upgrading.

One of the main factors is what you have for a shop, if you're renting or have a very small space the little machines can work well but if you have the space consider going larger. You won't pay that much more but you'll be able to do a lot more with a bigger machine.

About the only thing I'd tell you not to do is buying one of the really cheap Chinese units you see on eBay, that usually ends up in frustration.

The best move you've made so far is coming on here for advice, there's plenty of folks who have been there and done that so even though we may not all agree you won't find anyone here who will steer you wrong or put you down for considering any particular machine.

Patience is your friend here, take your time and figure out what you want to do as your first projects. This will guide what machines to get and if you can start small and work your way up.

This can be an expensive hobby but fixing up an older machine is a great way to learn if you have the patience.

John

 

[compact8]

. Is it possible to expect 0.001" precision

I have an Austrian-made Emco FB2 bench mill which weights about 280 lbs and I need quite a bit of luck to get that precision even with the DRO installed. one thou of an inch is 0.025 mm. The play in the XY table can easily be 0.015 mm, the flexing of the tool adds another 0.01 ~ 0.02 mm depending on the material of the work piece and diameter of the tool so that already adds up to 0.025 ~ 0.035 mm. Then there are other errors such as edge finding errors, imperfect clamping of work piece, dimension errors of parallels and other sources that I am still trying to be identify.

I have not owned or used the Sherline mills but from the photos the ridgidity of the machine is clearly poorer. Unless you can find a way to compensate for it ( e.g. I need to add at least 0.01 mm to the X/Y value to compensate for tool / head flexing even if carbide tools are used ), I would say it will be very difficult to get the precision you want.

 

[Watchwatch]

How much room do you have? Skip the benchtop if you have space.

You are in the Bay area. You can get a nice used Bridgeport clone for a couple grand. Tons of auctions and Craigslist. MrWhoope is always posting NorCal ads.


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