4 jaw chuck for Grizzly 9X19...

[Jasonb]

If you are worried about the jaws of a 6" chuck hitting the bed of a 9" lathe you are living dangerously, the max you should be gripping externally is 6" which leaves approx 2/3rds of the jaws in the chuck body, any more and there is a risk of damaging the chuck. With this amount of jaw in the body the tips of teh jaws will be around 8" dia or less

I ran a 150mm 4jaw in my 210mm lathe for about 20yrs with no problem.

Jason

 

[1hand]

The jaws will come out of the chuck before they will hit the ways on my 6" 3jaw.

 

[1hand]

Metal Butcher;

You get your 4 jaw and backing plate yet? I got my 5c and have the backing plate in the 3jaw right now to cut the boss down and turn it down for the 5" chuck. Just waiting on you to show me how too. Hate to have to throw this $35 piece of cast away cause I did it wrong...................

Matt

 

[Metal Butcher]

Metal Butcher;

You get your 4 jaw and backing plate yet? I got my 5c and have the backing plate in the 3jaw right now to cut the boss down and turn it down for the 5" chuck. Just waiting on you to show me how too. Hate to have to throw this $35 piece of cast away cause I did it wrong...................

Matt

All my stuff came in on Thursday and Friday. Been busy. I just came up from the shop after taking pictures and will post the pictures and comment tomorrow.

Show you? I have no idea of how I'm going to mount mine. I hope I didn't give you the impression that I knew how to machine a back plate.

 

[Metal Butcher]

I found this link and there's some good info that's helping me to understand what needs to be done to machine the back plates for the four jaw chucks.

It looks like I need to make a spacer to mount my plates backwards and spaced away from the spindle register to machine out the un-threaded step to match the smooth un-threaded area (register) on my spindle. only then can I reverse it to face the chuck side to fit into the chucks back side register.

http://www.armurerieduroi.com/pages/lathe/lathe_backplate.html

I knew this would not be easy.

-MB

 

[Deanofid]

Rick, show us some pictures of what you have to work with. Maybe one of us can get you on the right track.

Back plates sometimes don't have enough free bore on the start of the threads, (for a threaded spindle nose), to allow the plate to register. The last one I got didn't, and it was supposed to have been made specifically for the lathe I was working with.

That free bore is not as critical as the actual register surface between the back of the plate and the larger flat part of the spindle nose. It's mainly there to allow the plate to seat against the register without having a thread bump up on the smooth part of the spindle nose, directly behind where the thread ends.

Will the new backing plate fit in your three jaw chuck with the threads facing the tail stock? Do you have a face plate?

You have a saving grace granted here, in that you are doing a four jaw. You want to make a good job of it, of course, and be as accurate as you know how. However, if you are off a few thou on the match up between the recess in the back of the chuck, and the mating boss on the back plate diameters, it will not be a tragedy as it would with a three jaw chuck. It's better to learn on this than on a three jaw!

Dean

 

[Metal Butcher]

Hi all. The backing plates and chucks I ordered came in. Below are pictures of the items 'as received'. and a few of my observations and opinions. Please bear in mind that I have no formal training, and very limited 'self taught' machining experience.

Below are the 4" and 6" 1-1/2 -8 threaded back plates from LMS. The cast iron quality is very good and the machining is also very good. They will normally require further machining on the lathe to make them concentric with the machine there fitted to. Shown is the back side that threads up to the lathe spindle register.

Below are the register sides (face sides) that the chucks bolt onto . The register (step) for the chuck is oversize which will allow for a truing cut on the face and register diameter to insure a concentric running chuck. The out side diameters can also be trued up, or reduced in diameter to match the particular chuck being mounted.

Below is the first problem I encountered. The scribe is touching the lathe spindle register. The back plates will only screw up to the register. Some quick measuring shows my register to be 1.534. x 3/8" long. The back plates are 1.500 x 1/4", and 1.501 x 1/4" deep. Its my understanding that the M39 x 4 back plates screw right on the China Made 9 x 19 without a problem. When I called LMS I was told these would also screw right on. My machine is the first and more expensive version that was made in Taiwan, and they came with a 1-1/2 x 8 spindles.

On the left is the 4" LMS back plate, and on the right is the factory furnished 3 jaw chuck with back plate. The difference in the depth of the register recess can be seen.

The 6" and 4 chucks that I got off of the E-Bay seller. One came with a 'Shars' label that fell of. I believe that both sellers and 'Shars' sell the identical chucks made at the same specs. They will need to be de-burred since the edges, and especially the edges around the adjusting screws are razor sharp. This typical finish up work is not a problem for me and should take less than an hour. We all know the old saying "You get what you pay for" and for about $50 they seem to be a bargain. But understand that I don't think that de-burring and buffing the corners will make these chucks comparable to a $500 Bison brand chuck.

The chuck 'keys' are so poorly made that I could only laugh! Their appearance compared to my average work makes me feel like a 'Master Machinist'. This was expected and again is not a problem. There are three ways to deal with this, ignorine their crudeness, buy better quality self ejecting keys (could be problematic on an adjustable four jaw), or machine up a pair of beauties.

Not much to say about the back side. I did check all the threaded holes and they are deep and A-OK.

The jaws are relatvly tight with very little play. The adjusting screws are ground and fit the bores in the chucks well. The running faces of the teeth on the screws and jaws are ground, but not the quality I would expect. The rest of the non- running surfaces are for a lack of a better word "crude". Clean it, close it, and forget it. The only concern here is, will this affect my ability to adjust a work piece to zero, and walk away with my sanity?

I took apart the 4" for cleaning and de-burring. It made quite a bit of difference in the the way the jaws open and close. And with the sharp edges gone I feel it was worth the effort for cosmetic reasons, and more importantly safety reasons.

Do I recommend this brand? Sorry, but you need to make you own choice. For me the small amount of use mine will get it may turn out to be all that I need. And the small amount of money spent won't stop me from buying a better replacement if it becomes necessary. Only time will tell.

-MB

-MB

 

[Deanofid]

Hi MB;
Have you figured a way to cut the free bore in the backing plates yet?

About backing plate free bore and spindle relationship;
Something you may like to know about that particular dimension on backing plates is that it is often a fair bit larger than the diameter you are pointing to in the one picture. Having done a few of these jobs, I've seen similar sized spindles where the free bore in the plate is .005+ larger in dia than the unthreaded part of the spindle. That part doesn't have a lot to do with the alignment of the plate to the spindle. The two abutting surfaces on the plate and spindle are what need to match up nice and flat. That surface of your backing plate should be cut flat, already. Lets hope so.

Measure the free bore in the back of your three jaw mount, and I'd imagine it will show that there is plenty of breathing room between it and the unthreaded part of the spindle nose. It will give you a starting point, at least, for cutting the free bore in the backing plate threads.

Dean

 

[Metal Butcher]

Hi MB;
Have you figured a way to cut the free bore in the backing plates yet?

About backing plate free bore and spindle relationship;
Something you may like to know about that particular dimension on backing plates is that it is often a fair bit larger than the diameter you are pointing to in the one picture. Having done a few of these jobs, I've seen similar sized spindles where the free bore in the plate is .005+ larger in dia than the unthreaded part of the spindle. That part doesn't have a lot to do with the alignment of the plate to the spindle. The two abutting surfaces on the plate and spindle are what need to match up nice and flat. That surface of your backing plate should be cut flat, already. Lets hope so.

Measure the free bore in the back of your three jaw mount, and I'd imagine it will show that there is plenty of breathing room between it and the unthreaded part of the spindle nose. It will give you a starting point, at least, for cutting the free bore in the backing plate threads.

Dean

Hi Dean. I just finished up the four inch back plate. Unbelievable! It can't be any thing but beginers luck!

My spindle register is 1.534, and my original chuck plate is 1.536 a .002 clearance.

My boring job on the 4" is 1.5355!!!! Yipeeeeee.

I finished up the chuck register using a 'no go' 'go' cut and fit by cutting .0005 each try till it went on. I'm Guessing clearance at .0005 t0 .001 clearance which is fine since it is an adjustable 4 jaw.

The next two are gonna be a lot tougher. The one for the collet chuck has no spindle register at all. If I fail I'll have to get another back plate

-MB

 

[Deanofid]

Very good, MB! It's not beginners luck when you cut to a target, you know.

Again, it's not that free bore measurement that makes things accurate, though.
It's the two flat surfaces that abut, one on the back of the backing plate, and one which is the larger flat surface on the spindle that is perpendicular to the threads. Those two, and their relationship to the backing plate boss and large front surface of the plate are what put your chuck on center, and with its body parallel to the bed. That's why you cut the boss and front mating surface of the plate last.

Sounds like you know what to do. You're going to like having a four jaw. You can start cutting weird stuff, and enjoy doing it!

Have some fun, and show us your inevitable triumphs.

Dean

 

[Powder keg]

Great news MB!!! I'd call that skill in my book ;D

 

[Metal Butcher]

Dean! I did it again! This is almost to easy! I just finished up the spindle register on the 6" back plate since my last post. With the confidence from the first victory the second one was real easy. The final 1.536" diameter is slightly larger than the 1.5355 on the 4" back plate. I was my target as the 1.5355 on the 4'' seemed a bit small (tight) of a clearance compared to my original chuck (1.536").

I coated the face of the spindle register with Prussian Blue and both plates fit up flat on two separate tests of both plates. I got a small tube of this stuff in a box of machinist stuff at a flea market, and remembered reading that it's used to check contact areas between parts, when you mentioned a flat contact between the spindle and back plate it came to mind. It kinda feels like I just finished the first successful test run of a finished engine! :big:

I'm whipped (stress), so I'll pick up where I left off tomorrow or the day after.

If I could drink this would be a good time to crack open a keg of beer and invite all the members of HMEM! ;D

-MB

 

[Deanofid]

Great news on your success, MB!
You deserve a treat. I'm in the ginger ale crowd, too, but have found that a nice bag of M&M's is a fine reward for a job well done!

Dean

 

[zeeprogrammer]

this would be a good time to crack open a keg of beer and invite all the members of HMEM! ;D

I'm in! That is what you meant isn't it? I didn't misquote you or anything did I?

 

[Powder keg]

Does PBR come in a keg? If so, I'm in to ;D

 

[rake60]

Luck?

I call luck changing my 5 month old grandson's diaper and having him
pee over my shoulder rather than a between the eyes shot!

Hitting a critical size in a no second chance situation is a combination
of patience and skill.

Congratulations MB!
Not on your your luck, but on your skills!

Rick

 

[Deanofid]

Luck?

I call luck changing my 5 month old grandson's diaper and having him
pee over my shoulder rather than a between the eyes shot!

Hitting a critical size in a no second chance situation is a combination
of patience and skill.

Congratulations MB!
Not on your your luck, but on your skills!

Rick

Well said, Rick!

Luck is running blindfold through a dog kennel and getting nothing on your shoes.

DW

 

[Metal Butcher]

Thanks guys. Your confidence that I have skills (vs luck) is appreciated. :bow:

When I blotch one up we'll call it a 'lack of skill', (vs bad luck). ;D

The next step is to place the chuck mounting holes were they belong. I'm leaning towards making a single transfer screw from a beheaded metric bolt. I could drill and tap a small scrap cylindrical block, split it with a saw so it acts like a collet to hold the bolt while I turn a short point on the end. Then I could mill or file two flats on the point end to install and remove it after marking the spot for the first hole. the second hole would be marked after using a line up bolt in the first hole and so forth.

To bad they didn't provide a drilling template. Seems like you get one with everything these days that requires more than one hole.

Hey! Where are you all at? The keg of PBR is almost empty. And there's quite a few guys and gals just about done emptying out my liquor cabinet. :big:

-MB

 

[Deanofid]

No bolt circle diameter given, MB?

If not, it's fairly easy to measure, since the back of the chuck takes four mounting screws.
Put in two of the screws in holes farthest apart in the back of the chuck. Measure the distance from out side diameters of the screws, subtract the diameter of one screw, and that's your bolt circle center line.
Halve it for your radius and mark it down.

Put that scribe you have in your tool post, on center height and centered in the spindle bore. Zero your dial, and crank your cross slide over the radius distance. Run the scribe up to the backing plate, give the spindle a turn (by hand) and you have the bolt circle scribed.
Put it on the milling machine, center it, and use the mill dial coordinates to spot your four holes. A really easy one with only four holes involved. Ten minute job, and everything's jake!

Dean

 

[Metal Butcher]

I got the 4" 4-jaw chuck mounted today. I used the transfer screw method of locating the drilled screw clearance holes in the back plate. It seemed to be an idiot proof way of getting the job done. Dean, thanks for taking the time to show me the method that you use, It's probably a more standard practice method but I felt a little unsure of it. The information you provided will be used on a project in the future. I got the idea of using a transfer screw from the LMS site. After seeing what they look like I just had to try my hand at making one. It offered a simple method that would eliminate the possibility of a mistake that would be hard to correct. Actually impossible would be more accurate.

Luckily I had some M8 bolts in a small box of metric hardware, and was able to make a throw away transfer screw. I chucked up a piece of scrap aluminum rod 1/2" x 1" long and tapped it shallow. I screwed it in till it bottomed out and cut off the excess along with its head. I machined a short length of the tip to a point. and filled two flats to aid in its removal. With a propane torch I heated it cherry red and dipped it into Kasenit and re-heated it before quenching in oil. I didn't 'draw' back the temper and used it as is since only the surface was hardened.

The first one on the left was used before heat treating, and flattened right out on the fist attempt without leaving even a slight 'punch' mark. The one on the right was used to mark all four hole locations. The flattened one on the left was heat treated first and by mistake, dam eye sight again!

After the four holes were drilled the bolts were snugged down. I loosened each one individually about a 1/4 turn. Each one had equal side-to-side play meaning there was no binding between the bolts and back plate. The M8 bolts are .309" in diameter, and the clearance holes were drilled undersize and reamed to .3125. Since its the register on the back plate that positions the chuck, the nearly .004" play in the bolts is just fine.

Since I like the look of protruding 'cap screws' I didn't counter bore for them. They
do not screw in deep enough for my taste, so I will pick up some longer ones on my day out shopping. The four cylindrical adjusting screw keepers, that go in from the back of the chuck are about a 1/16" below the surface of the recessed back. This concerns me a bit since it will allow the keepers to shift outward reducing their engagement with the adjusting screws. To eliminate this concern four thin disks cut from a sheet of rubber will be glued to them on the back with contact cement.

The chuck sure looks good mounted on my lathe. I'm enjoying this project and will continue with finishing up the two other back plates for the 6" four jaw and the 5" 5-C collet chuck. And I'll also continue posting as the project progresses.

-MB