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wondering about getting a cylindrical grinder

idacal

Hot Rolled
Joined
Aug 9, 2011
Location
new plymouth id
I have been thinking about a cylindrical grinder for in the shop for a while now. I have room for one more machine beings how I gave the shaper to my brother. my lathe is fairly worn out but its really nice when its time take material off but the Finish is horrible and its not very often we actually have to make a bearing fit but its annoying to say the least. Im getting getting out of round bores and shafts. bearings are several thousand dollars even on eBay and surplus sites the main bearing is a 3.1875 bore which of course isn't a common size and the ways have a I think it was .015 of drop up by the chuck. so lathe is pretty much shot. I was looking at another lathe a leblond that is local but compared to my monarch its loud I dont know if that's just the nature of them. haven't checked the gears yet on the leblond but I don't need something that has to be babied. I have tried all the tricks on the lathe i have read here to improve finish and accuracy its just tired.long post but my question I'm looking for basically for a 10x 36 or so universal cylindrical od id grinder. seems like i can pick one up for around 5 grand but not sure what route to go that or a smaller newer lathe (dont have room for both)but even those still will not make a ground type finish. I know a good machinist can make my lathe work but I want to be able to hit numbers without holding my breath just the right way.
 
You're almost certainly better off getting a functioning lathe, or repairing one you have. Unless you're really doing a lot of precision shafts and bores, a cylindrical grinder is slower to set up, and due to wear an older one may not do much better than what you've got.

The worn ways can be lived with if you sneak up on your diameters, but a bad bearing is tougher to band-aid. Any chance that there's a spindle bearing with a bigger ID but correct load capacity, OD, and width? You might be able to sleeve the spindle shaft's OD to make the more available and cheaper bearing work.
 
You cant solicit more work with a better lathe but you can solicit more with a od grinder.
 
The 74 year old B&S #4 Universal (14 X 60) does just fine - but I only have to please myself

P1000645sm.jpgP1000647.jpgP1000652sm.jpg

Flood coolant naturally goes hand in hand with grinding

Three main requirements after flood coolant are first class centers and dressing diamonds and of course the right wheel for what you want to grind on
 
Doing mild steel parts and quick to go between centers I think you can't beat a decent lathe.

QT:[universal cylindrical od id grinder. seems like i can pick one up for around 5 grand]

You might be better off putting bigger bucks into a very good lathe.

I am all for grinders, but you have to make a second operation to go from lathe to grinder.

I have found that a lot of problems come from poor centers and so advise a center lap abrasive wheel
(9 bucks each but they are worth it.)

Norton Center Lap Mounted Grinding Points - Norton Abrasives - Bonded Abrasives - Norton Abrasives - Shop Manufacturers
 
I was cutting a taper on my lathe roughed it in and was going to scrap it had humps and valleys all kinds horrible finish problems.that was with sharp tools for kicks and giggles I put on my toolpst grinder it took .020 to finally clean up all the tooling marks and hills and grooves. it blues out right with a ring gauge afterwards though. I don’t use the tool post grinder muchI think that was the second time. I hadn’t thought about sleeving the shaft I was trying to over complicate it and get a metric to fit I an get the next size up bearing for a few hundred dollars and there is multiple bearings available to try i will research doing that. I’m used to how quiet my lathe is I watch YouTube’s and other brands lathes in person and they just seem rackety.
 
A good condition lathe should get near grinding finishes with a radius nose bit/insert.

Then for that rare part the needs better, one minute with a crocus cloth or oiled wet automotive paper.
 
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I put on my toolpst grinder it took .020 to finally clean up all the tooling marks and hills and grooves.

If you're not exaggerating, that's really, really bad. .020"?? Are you sure it's the front spindle bearing (dual or single?) that's the issue? Nothing about the chuck/jaws being whacked, or anything else that could be moving?
 
I wish I was exaggerating on the amount taken off I have checked the runout on the chuck case, .0005.the face of the chuck mount almost no movement. a bar in the chuck and wiggle maybe .0005 Thats when it’s not under power. Hand rotating Indicator on a test bar it all test good but when in a even a few thousand cut it’s all over everywhere I have tried different preload on the bearings Same results iit looks like it turns 20 -30 turns and the cut is a different depth.
 
I love grinders but the capabilities of good CNC machines have reduced the need in general and nobody wants to pay for grinding. Fix yours or get a better lathe.

If he can actually grind to a ½ thou. on the same lathe, it sounds like he needs better tooling, technique and maybe a chuck. Then a lathe.....in that order.
 
First off, either fix current lathe, or get a better lathe, a cylindrical grinder is not the answer for a bad lathe. I have a nice grinder, but it does not get used much. If you decide you really want one, keep your eyes open, they can be had for less than 5k if you are patient.
 
If the lathe seems/is tight and having problems perhaps using negitive tooling on mild steel..That can double the cutting forcrs and cause the tool holder to swing out of position. Good to have positive cutting tool, very sharp edge and perhape a .02 radius.

QT: [Same results iit looks like it turns 20 -30 turns and the cut is a different depth.}
Sounds like the tooling is moving, cuting tool holder, tool post, Tool bit or insert.

idacal (OP) might tell what cutting tool (bit/insert) he is using.
Might show a photo of it as set-up for turning.

Some set-ups like extending the compound far to the right can cause saddle rocking, and poor cutting action may result.
 
I have a free Grand Rapids #60 Grinder in good condition ready to run.

If the lathe seems/is tight and having problems perhaps using negitive tooling on mild steel..That can double the cutting forcrs and cause the tool holder to swing out of position. Good to have positive cutting tool, very sharp edge and perhape a .02 radius.

QT: [Same results iit looks like it turns 20 -30 turns and the cut is a different depth.}
Sounds like the tooling is moving, cuting tool holder, tool post, Tool bit or insert.

idacal (OP) might tell what cutting tool (bit/insert) he is using.
Might show a photo of it as set-up for turning.

Some set-ups like extending the compound far to the right can cause saddle rocking, and poor cutting action may result.

I have a Cylindrical grinder I saved from the scrap yard. 6000#
of old iron available for free.
also a hollingsworth medium Shaper, aprox 5000# also free.
All in good working order.
Hope this doesn't violate any rules.
Just a Swarf Nob
 
this thing will barely hit .005 if im lucky that was how much I had to grind just to get the tooling marks out by then my part was set way back in my ring gauge but the taper still blued out its not a small lathe. monarch series 60 16 x154 I like the length for the personal hydraulic stuff I do . i have used tpg tooling, hss tooling, negative rake tooling, and even with all the tests I can't find where the slop is coming from. I had the compound locked down with c clamp it was on 2" stock. but back to the grinder sounds like people that have grinders dont use them much is the feeling Im getting here. with the 2x4 test im only getting .0005-.001 and thats with a lot of pressure
 

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That's a good size machine. If you only got such a small amount of movement in the spindle while giving it good pressure, I'm reasonably sure it's not the spindle bearing.

You need to find out where the lost motion is coming from. If the tool post grinder moved the saddle more to the right that the cutting tools, that last bit of Z way close to the spindle may be shot, if you can work further out you may get better results. Could the whole saddle be rocking?

One tricky but not insane thing you can do is set up a steady rest about 12-20" away from the spindle, chuck a ~4" (or whatever) piece of stock to run in it, then cut thread for a spin-on chuck that would then become the working chuck. Obviously not ideal, and you'd want to take lighter cuts, but if the machine really has a lot of wear in that last foot or so of bed in front of the spindle this method would move the saddle away and give you some utility. Just no through-spindle work, of course.

Otherwise, spend some time with a couple test indicators isolating elements and checking for relative movement under load. I'm sure something is happening, I'm just not convinced it's the spindle.
 








 
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