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Cylindrical grinder mag chuck

vbavaro

Plastic
Joined
Sep 18, 2021
Acquired a Lian Feng LF-800G universal cylindrical grinder. I need to mount a 8”-10” magnetic chuck on the work head and do some I.D. Work. I don’t know a lot about cylindrical grinders especially this brand of machine but I have used other brands a handful of times. I don’t have any documentation on it and very little info online. Is this a standard spindle type for a cylindrical grinder? If so what do I need to adapt a chuck? Anyone have a user manual out there?
 

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Acquired a Lian Feng LF-800G universal cylindrical grinder. I need to mount a 8”-10” magnetic chuck on the work head and do some I.D. Work.
Have never seen anyoone use a mag chuck for ID work. Rotary surface in a universal id grinder yes but not id. There's generally not enough surface to hold the work securely.

People use a three jaw or four jaw or a fixture of some sort, normally.
 
I had a friend who used a mag chuck like a mag faceplate. He would mag hold flat-faced parts for OD and ID and mount a flat rear-faced center for a between centers job. He would bring me parts so I could analyze and make special mandrels for his grinding. I would make the mandrel on a B&S 13 grinder and had access to a huge bunch of centered obsolete centered stubs so often there would be one close to his needs. Mostly the subs were hard but for short-run parts, even a mild CRS mandrel was good. Seemed he did mostly short-run jobs/parts and made pretty good bucks doing that.
He had his machines in a shop he called the swamp because at rain the floor would be flooded.
Yes, some jobs were blocked in like one would do on a SG, some in a mag chuck held V block, and some just off the mag.

It seemed logical because so very often a good/best collet will run out 2 or 3 tenths, and with knocking in a part/collet holder one can get near zero. Even a mag set collet holder and a collet with a line-up mark, once knocked-in will run truer than most headstock grinder spindles. If one has a zero close headstock spindle and the collet runs out 2 tenths that is the best you can do, having a one-tenth limit/target your shot.

Quick at one-tenth and less is a good asset/talent to get work once customers know you can do that.

With being careful a part/job that you cant push with two fingers can be ground by counting sparks (Watching the spark flow)

Knock in the chuck with putting a line-up mark on the chuck holder and a corresponding one on the headstock spindle, then grind the face dead flat using a flat parallel for a checking gauge and note where your headstock is mounted on the table, and where it is to the protractor number(S).
Not uncommon to need a spec corner so make a chat of wheel for corner chart. Find that at abrasive grit size screen.
 
The normal UNIVERSAL set up will be able to drive the spindle with whatever tooling bolts/attaches to that spindle or hold the spindle still and rotate only a dog driver on work between two dead centers - one of which is held in the non rotating spindle

I would imagine the slideable dog we can see in the photos has something to do with selecting which of those two choices

Where those ideas came from 130 years ago

Brown & Sharpe Mfg. Co. - Publication Reprints - A Treatise on the Construction and Use of Universal and Plain Grinding Mach | VintageMachinery.org

have fun
 
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Having the mag set up being a mag in the machines taper I described in post 3, one might also want to have a center point, perhaps a good live center, a good 4 jaw chuck the fits the machine taper and a steady rest. Note thst all taper for devices should have a line-up mark to the spindle head so at removing and replacing they might still run close. It is not uncommon to grind the headstock center in place to rule out the head taper error.

I don't think the headstock mag is a very common method. It may not be suitable for large work.

Only a very good 4jaw chuck would be suitable because much grinder work is held to close tolerances.

Some ID and OD work is held with the but end held in a chuck or center, and the out end in a steady so to hold high accuracy and alignment of one end to the other. Much OD work is held between centers.

Good to have an indicator mounted to the table swing so to adjust the part straightness, you move the table half the error based on the part length and how far you are from the table pivot point. Often one will hand feel the wheel to the part after measuring both ends to get .001or so close before setting on the indicator fo final adjustment to straight... the cross feed dial is used as an indicator to adjust the movement of the part.

The ability to make straight quickly is the art of fast grinding. One can waste a ton of time traveling end to end a number of times. One travel should get one to .0002 - .0005 if you think about the length of the part and how much is past the table pivot point.

Often you cant take a grind and measure because you may have little or no stock on the part. sometimes one may need to move the part's center back to zero before grinding that part. I used a Norton center abrasive point for this task.

Have a taper cleaning device to keep all grits out of the taper.

Center lap
Norton 1 X 2 In. 1/2 Spindle A80-VVM Center Lap Mounted Point 80 Grit A/O, 61463622926 | Hillas.com
 
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Yes, the spindle is a MT#4. That’s how I recall the Kellenberger I used years ago. A chuck with a MT. What holds all this rotating mass in place? I would think some sort of draw bar to keep the chuck seated into the Morse taper?
 
Yes Drawbar
Kellenberger is a MT5 isn`t it ?
I have seen the mag chuck beeing used on a relative small surface
Small and bigger items
Indicating was real quick
Just a few taps with a plastic hamer

Peter
 
For i.d. grinding you would like the wheel to reciprocate through the hole, out the other side. I'd just like to see how this is done with a magnetic chuck ?

Agree 100% with that, wheel going through a through hole. Perhaps a 4 jaw set on the magnet, or some kind of collet holder or a V block

I have not used a mag chuck in this way..but my buddy Rick did most if not all in this way.
I think one would be like a surface grinder chuck, so not wanting to remove it often if ever...and not regrinding it in again.

Repaced with a line-up mark it might remain to be close...close enough(?).

Oh, and with a collet holder, one would need to take care not to move it from the set position when tightening...same with a 4jawod or v block.

Plus if one ground hard enough to move the part on the magnet, it might crash.
 
I’m form grinding a shape inside a a bore with a wheel dressed to the angle and radius I need. It’s touch up work. Blending an angle back in after sharpening so no reciprocation needed. Blue it up and blend it in then polish. As for the kellenberger. I was using it as an example the one I used had a chuck that slipped into the Morse taper. It probably was a MT#5. My Ling Fang machine is an MT#4. I just don’t remember what held it into the taper. My drive plate is very flimsy I think it would need to be removed and replaced if I were gonna adapt a chuck to the plate instead of in the taper.
 
An old thread, strange that it popped up?
A chuck can be flat mounted to the face magnetic chuck. The work head taper is not very important because you grind the magnetic chuck to be square and flat in place.(and centered for balance). Made with it having a line-up mark to line up to get it closer to the same if you remove the magnetic chuck from the headstock spindle mag chuck. The chuck being mag added should also be centered each time it is installed by eyeball, and then indicating the part to be ground. The chuck flatness should remain good at each installation, so just need a bit of OD tap in at each install / or indicate the part as it is held in the chuck
 
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