Refurbishing an old adjustable 3 jaw chuck

I got this interesting old 3 jaw chuck with my vintage Karger lathe that looks to be adjustable. In this video I clean it up a bit and find out how this thing works.
I would like to find out when/where and by who this chuck was made. So I you have and info please put it in a comment or sent me a PM.
Here's the original patent from 1946: goo.gl/cHrchp
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[@fellovercliff4525]

I have that exact same chuck on my 1956 Australian made Hercus 9" lathe, has the same markings as yours. The lathe was made down under but not sure who made the chuck. I also recently did the strip and clean and had a hell of a time trying to true it up again.

[@mrpete222]

Nice video----Thats an "adjusta-tru" chuck. Thats Buck's trademark name. Most chuck makers produce one. I love them.

[@Rolingmetal]

I think this is a bit older. It uses a patent from 1947. And it has only 3 adjustment screws.

[@Xynudu]

That was really interesting. I've never seen a scroll chuck like that before, and the way it adjusted the eccentric off set is very clever. The final result was as good as you can expect for most scroll chucks - and excellent for an old one like this. Thanks for posting. Cheers Rob

[@Rolingmetal]

Thanks Rob. I think this old girl might still be very usable. Although a 3 jaw in 4 jaw design should probably work better.

[@Loserplatz]

The de-smurfing is an especially important step, I agree.

[@Rolingmetal]

They must have run out of masking tape.

[@lv_woodturner3899]

I love this video. Thanks for deciding to clean up the chuck and post the video. Very interesting. I was not surprised that the initial re-assembly had more run out. I have a 3 jaw scroll chuck with 4 screws to adjust the body to be true. It does take time to get this to run true. I can imagine it is much more time consuming with the 3 jaw design. I saw the comment by Tkkcustomknives where he found the patents. Well done. A mystery solved perhaps. This was a high technology chuck for its time. I also grease the spur gear and pinions and use way oil on the scroll and jaws. The chuck may now be running true. The small amount of runout could be the piece of steel you have mounted for the dial indicator. This chuck is worth keeping. I am happy to assist making new screws for the backing plate. Just let me know dimensions. I think a thicker shaft in the backing plate may help.

[@Rolingmetal]

Hope you'll love the next video as well. Uploading as I type :) It very nice to have seen the original patent. But I still would like to find out who made it. If I keep the chuck I also need to keep the lathe as it wont fit the old restore lathe. It will fit the old wood lathe but I have decided to sell that machine. To be honest I'm starting to like the old smurf lathe :) I think I should be able to buy those screws locally. But thanks for the offer.

[@ludovicobonsignore4284]

"The best rust removal is when someone else does it for you"... AHAHAHAHAH That one was great!!! I agree!!! From my experience, electrolysis is fine, but a bit too much of a pain in the butt, unless you really need to take away the least possible amount of material. Bronze brushing by itself is generally safe and effective, sometimes a bit too harsh, if you want to preserve surfaces as true as possible. And you breathe a lot of metal dust. Personally, I found very helpful to dip the pieces into a mix of white vinegar and a bit of kitchen salt in big grains, for about 24 to 48 hours. Then, a light bronze brush will do the rest. It is a fairly simple yet effective way, and it also helps to clean up grease and other impurities. But, looking at your skills, you probably already knew all this. Thank you very much for sharing your experience! Ludo

[@mahocnc]

You see a arrow near one of the 3 Pinion on outside of chuck...you might wonder why...use this one only for best repeating runout. You can use another pinon but make sure it's always the same one, that's why one is marked.

[@Rolingmetal]

Isn't that also why the have a "0" on modern chucks?

[@mahocnc]

That's right

[@HappyHands.]

little screws used to adjust the backplate alignment before tightening the back plate back down

[@Rainbows871]

As I see someone else mentioned 1/4" = 6.35mm (slightly bigger than M6) BSW 1/4" = 20 TPI = 1.27mm pitch, very close to the 1.25 In england some cars used to have metric threaded bolts with imperial hex heads. Maybe you had an imperial screw with a metric head? Watch out it will probably be a whitworth (55 degree) thread so won't match american fastners (60 degree). I don't think 1/4x20 is a standard american size. Of course how easy it is to find obsolete british fasteners in germany is a good question. Maybe old car restoration places? Or just ship it in from the UK. Old video I know but you might still have the chuck hanging around :P

[@Rolingmetal]

Thanks for pointing that out. I still have the lathe and at some point I'm going to make a better motor mount for it and also install a vfd drive.

[@adamj91]

Those screws are probably 1/4" x 20 Non metric at all ;)

[@Rolingmetal]

Could be. But they did fit the 1.25 pitch of my gauge very nicely. Unfortunately I don't have an imperial gauge. Just a metric/withworth one

[@adamj91]

That's right becuase 20TPI is very close to 1.25 (1.25 is exactly 20.32TPI) M6x1.25 is not very common thread anywhere in the world, when 1/4 x 20 is standard in UK/USA, so it also happens in Europe. Check the diameter, if its around 6.35mm, then it's certainly 1/4"

[@Rolingmetal]

You're probably right. The diameter is closer to 6.35 then 6.00mm

[@joedellaquila9766]

Rust removal by electrolysis is actually really easy. I bet you could do it.

[@Rolingmetal]

I tried that maybe 10 years ago. I was not impressed. You still need to do a lot of cleaning and scraping and it takes forever. I bet most of the people on youtube showing rust removal by electrolysis never use it again.

[@Rolingmetal]

More about this little old pattern makers lathe can be found here: goo.gl/ecfiPm And here's the original patent for this chuck from 1946: goo.gl/cHrchp

[@davidmclean5067]

DeSmurfing? HAHAHAHA! Excellent!

[@HanstheTraffer]

Adjustable 3 jaw. Arkansas Germany. Just north of Berlin? ;-)

[@garymucher9590]

Interesting chuck for sure. Did you know for certain that the dead center was true before using it to setup the chuck? When you are talking about tenths of a millimeter, everything has to be verified. JMHO

[@Rolingmetal]

It's a piece of 16mm shafting material. Seems to be pretty true but I'm not 100% sure.

[@felipefletcher8382]

Good product

[@antonborisenko2494]

Chuk like Pratt Burnerd - Griptru

[@Rolingmetal]

Its a very old chuck design based on a Dutch patent from 1946. Patent document: goo.gl/cHrchp

[@antonborisenko2494]

Very good chuck - but internal external jaws - deficit

[@georgewhitfield2176]

Nice.

[@Rolingmetal]

Certainly nice enough for its age.

[@khemchand8231]

super