Finally getting my G0602 setup!

[gerritv]

I don't have an answer to how much preload but worst case I would tighten the nuts up 1/8 turn at a time while checking the deviation under load and also whether the bearings heat up when running for 10-15 minutes. If too tight the sound will change as will the temperature rise.

RJ pointed you to the Grizzly spare parts, this is the link to 3-jaw chuck backplate which is 5" https://www.grizzly.com/parts/Grizzly-CHUCK-BACKPLATE/P0602054-2

 

[gun410]

I don't have an answer to how much preload but worst case I would tighten the nuts up 1/8 turn at a time while checking the deviation under load and also whether the bearings heat up when running for 10-15 minutes. If too tight the sound will change as will the temperature rise.

RJ pointed you to the Grizzly spare parts, this is the link to 3-jaw chuck backplate which is 5" https://www.grizzly.com/parts/Grizzly-CHUCK-BACKPLATE/P0602054-2

Thanks for the link, that backplate should work great for the er chuck! I’m out of town right now but when I get back I’ll be sure to adjust the preload, but how would one check the bearing’s temp when their enclosed in the headstock? Last thing, are the G0602’s stock bearings good quality? If thinking it might be worth it replace them with something better to avoid some headache.


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[gerritv]

Like I said, unless you know those bearings are bad, e.g. noisy, crunchy, leave them alone until you sort out the present issues. This is my opinion based on past experience going down multiple paths at the same time
Replacing the bearings is not trivial and requires you to make some tools first, with a lathe. There is at least one thread here on that topic. In the end you will be where you are now, how much preload do you put on the bearings.
As to how hot is too hot, I imagine the bearling location in the headstock will get warm. If you also have trouble turning the spindle by hand then you are definitiely in the too-tight realm. I would start by tightening 1/8 turn, check, do it again, check etc until you noticebly reduce the movement. At that point call it close enough for now and do some test cuts. If after 15 minutes of running you feel significant heat at the bearing locations, back off the preload 1/16 turn.

 

[gun410]

I got back in the shop and I gave the spanner some more torq which helped quite a bit but it still moves a bit, it seems the problem is in the headstock, the indicator moves if you press on the front of the headstock. It seems my bearings are decent so I’ll probably leave them for now, but my first concern is getting the lathe rigid & solid for smoother cuts. I hope this problem isn’t too serious and I can get it cutting decently.

 

[mikey]

Preload setting can vary by the manufacturer and quite often they recommend adjusting preload to achieve a certain amount of end play. I don't know if Grizzly does it this way, though; you have to check the manual. I own an Emco Super 11 CD lathe and it has P6 spindle bearings in it. The way the Emco engineers say to do it is really simple. With the lathe cold, you mount a 3 jaw chuck on the spindle and spin it by hand as hard as you can. Preload is adjusted to allow the chuck to make 1 to 1-1/2 revolutions before stopping. As primitive as this might sound, it works. My spindle has zero run out and has maintained that since the late 1990's. The headstock gets only slightly warm, even after prolonged running, and the lathe makes less than 73 decibels at the highest speed.

With regard to the finish you are getting with that HSS tool, it might be the material. If that is 1018 then no tool will produce a nice finish except maybe a shear tool taking cuts of a thou or two. Your tool, what I can see of it, only has nose radii on it. It's hard to tell but it looks like side and end relief is minimal and there is no side or back rake. Such a tool will not cut well. There is a lot more to tool geometry besides the nose radius and perhaps a bit more discussion on the tool might help you. If you post some detailed pics showing all sides of the tip of the tool and part of the shank, maybe we can help.

 

[markba633csi]

The shape of the hss tool bit in post #18 looks incorrect- rake, relief angle, etc.
Need to practice that, you should have no trouble getting fairly smooth finishes on steel with only minor tearing
-Mark

 

[gun410]

Preload setting can vary by the manufacturer and quite often they recommend adjusting preload to achieve a certain amount of end play. I don't know if Grizzly does it this way, though; you have to check the manual. I own an Emco Super 11 CD lathe and it has P6 spindle bearings in it. The way the Emco engineers say to do it is really simple. With the lathe cold, you mount a 3 jaw chuck on the spindle and spin it by hand as hard as you can. Preload is adjusted to allow the chuck to make 1 to 1-1/2 revolutions before stopping. As primitive as this might sound, it works. My spindle has zero run out and has maintained that since the late 1990's. The headstock gets only slightly warm, even after prolonged running, and the lathe makes less than 73 decibels at the highest speed.

With regard to the finish you are getting with that HSS tool, it might be the material. If that is 1018 then no tool will produce a nice finish except maybe a shear tool taking cuts of a thou or two. Your tool, what I can see of it, only has nose radii on it. It's hard to tell but it looks like side and end relief is minimal and there is no side or back rake. Such a tool will not cut well. There is a lot more to tool geometry besides the nose radius and perhaps a bit more discussion on the tool might help you. If you post some detailed pics showing all sides of the tip of the tool and part of the shank, maybe we can help.

Hi Mickey thanks for the input, I couldn’t find anything about the preload in the manual but I tightened a little more and the runout isn’t too bad. I took a video to show what I mean but if you press on the spindle or the headstock you can get over .0005” of movement. I have no idea where this is coming from but I’m pretty sure this lack of rigidness is somewhat causing the poor surface finish. I can’t exactly remember what steel this is but I’m fairly certain it’s 1018 or 1045. I also found out I’m going to have to build an separate independent leveling system for the lathe. I’m thinking I have a slight twist because if I put the indicator on the headstock and push the spindle it doesn’t move.

I’ll also post some pics of the HSS tool I mad but it does have some relief angles cut on the cutting edges. I was under the impression a larger nose radius produces a smoother surface finish.

 

[markba633csi]

Something like this is what you are after: with a steeper angle on the front

 

[mikey]

Hi Mickey thanks for the input, I couldn’t find anything about the preload in the manual but I tightened a little more and the runout isn’t too bad. I took a video to show what I mean but if you press on the spindle or the headstock you can get over .0005” of movement. I have no idea where this is coming from but I’m pretty sure this lack of rigidness is somewhat causing the poor surface finish. I can’t exactly remember what steel this is but I’m fairly certain it’s 1018 or 1045. I also found out I’m going to have to build an separate independent leveling system for the lathe. I’m thinking I have a slight twist because if I put the indicator on the headstock and push the spindle it doesn’t move.

It is very difficult to say where that half thou of movement is coming from but if I had to guess, I would suspect the spindle bearings are it. You have to remember that your lathe is built to a price point and the maker will use cheaper bearings. If you were to install accuracy-class bearings like ABEC-5's, it would be better. The cost for ABEC-5 bearings to fit your lathe would not be unreasonable; if you plan to keep your lathe then this might be something to consider. However, I suggest you put this on hold while you get the lathe aligned and leveled.

I actually have to disagree with you with regard to the headstock and spindle causing a poor finish; too many guys own that same lathe and can produce acceptable finishes. I think the tool you're using and possibly the material you're cutting is more likely the issue. This is a good thing, by the way, because I think we can definitely improve the tool. We'll get to the tool in a minute.

Putting an indicator on the headstock and pushing on the spindle tells you essentially nothing about the levelness of your lathe or anything else. There is a process to check and set the level of the lathe that I won't go into here because that is a HUGE discussion but you're going to be okay, it isn't hard to do. I suggest you start a new thread and ask the guys for advice on aligning the headstock and leveling the lathe.

I’ll also post some pics of the HSS tool I mad but it does have some relief angles cut on the cutting edges. I was under the impression a larger nose radius produces a smoother surface finish.

You're right; you do have some side and end relief - thanks for the pics. A large nose radius does produce a nicer finish BUT it also deflects like crazy unless you take tiny cuts. Moreover, you are cutting with the tool mostly perpendicular to the work piece and the area adjacent to the nose radius is rubbing; that is where your poor finish is mostly coming from. In the screen shot below, the area of primary contact is in green and the area that is probably rubbing is in red:



On a turning tool, the area of contact matters but even more important is that that contact point must be the ONLY point in contact. Therefore, the shape of the tool matters. You are cutting with the end cutting edge, which is fine. However, too much of the end edge is touching the work and the tool is rubbing. Typically, rubbing results in a torn, rough surface and that is exactly what you're seeing.

Luckily, as Mark points out, fixing this is easy. You just need to learn to grind a better shape with the proper tool angles and you'll do just fine. To save my fingers let me refer you to a write up that might help you. We also have a huge thread going here that might be of interest to you.

You're going to be fine. Work on getting the lathe aligned and leveled, then come on over to the model tools thread and let's hash out the tool. You'll be up and running in no time.

 

[gun410]

It is very difficult to say where that half thou of movement is coming from but if I had to guess, I would suspect the spindle bearings are it. You have to remember that your lathe is built to a price point and the maker will use cheaper bearings. If you were to install accuracy-class bearings like ABEC-5's, it would be better. The cost for ABEC-5 bearings to fit your lathe would not be unreasonable; if you plan to keep your lathe then this might be something to consider. However, I suggest you put this on hold while you get the lathe aligned and leveled.

I actually have to disagree with you with regard to the headstock and spindle causing a poor finish; too many guys own that same lathe and can produce acceptable finishes. I think the tool you're using and possibly the material you're cutting is more likely the issue. This is a good thing, by the way, because I think we can definitely improve the tool. We'll get to the tool in a minute.

Putting an indicator on the headstock and pushing on the spindle tells you essentially nothing about the levelness of your lathe or anything else. There is a process to check and set the level of the lathe that I won't go into here because that is a HUGE discussion but you're going to be okay, it isn't hard to do. I suggest you start a new thread and ask the guys for advice on aligning the headstock and leveling the lathe.



You're right; you do have some side and end relief - thanks for the pics. A large nose radius does produce a nicer finish BUT it also deflects like crazy unless you take tiny cuts. Moreover, you are cutting with the tool mostly perpendicular to the work piece and the area adjacent to the nose radius is rubbing; that is where your poor finish is mostly coming from. In the screen shot below, the area of primary contact is in green and the area that is probably rubbing is in red:

View attachment 331674

On a turning tool, the area of contact matters but even more important is that that contact point must be the ONLY point in contact. Therefore, the shape of the tool matters. You are cutting with the end cutting edge, which is fine. However, too much of the end edge is touching the work and the tool is rubbing. Typically, rubbing results in a torn, rough surface and that is exactly what you're seeing.

Luckily, as Mark points out, fixing this is easy. You just need to learn to grind a better shape with the proper tool angles and you'll do just fine. To save my fingers let me refer you to a write up that might help you. We also have a huge thread going here that might be of interest to you.

You're going to be fine. Work on getting the lathe aligned and leveled, then come on over to the model tools thread and let's hash out the tool. You'll be up and running in no time.

I was suspect of the bearings as well, but let me see if I can explain what I did better. The first time I use the indicator I mounted the mag base on the carriage so when I pushed on the spindle i think it slightly lifted the headstock casting away from main frame casting (way casting). Because when I put the dial indicators mag base on top of the headstock and push the spindle it doesn’t move. The headstock is aligned so I think I just have to tighten the headstock down, but correct me if I have it wrong. I wasn’t trying to see the level ness of the lathe but to cancel out another variable to narrow down the movement to just the bearings, I hope that makes sense.

I get what your saying about the tool shape, I would rather not worry about that right now so I swapped it out for a carbide tool with some 17-4 SS . I got a better surface finish but it’s seems like there are still some issues (can’t get a smooth finish without rubbing it messing up), I’ll try to get a good picture later of it. But I have a video of turning that as well as trying to part. I’m still having some bad troubles with parting and it constantly stalls the machine out when trying to cut (tool will get caught into work and instantly stop the machine), do I have a problem or is my lathe just too small for the operation?
Lathe was at 560 rpms, and I used a mgmn 3mm wise carbide parting tool & a ccmt insert for the turning show below.