small friction drive chucks

[Sam Fleisher]

Beating a dead horse I know so I thought I'd do a poll.

I have a set of axminster O'donnell jaws that come in 50mm - (2inch)
38mm - (1 1/2")
25mm - (1")

That is when the jaws are perfect circle/ optimal size. I want to make some small jam chucks for some 3 -4 inch bowls I need to finish turn that have various sized recesses and tenons which is why I was going to make a jam chuck for each size jaw. I'll be making them out of hard maple and would like the most stability for re-usability.

**EDIT**
I keep calling this a jam chuck, I guess I should be saying friction drive chuck because I'm talking about the type that you put inside a bowl with a piece of drawer liner or foam and use the tail stock to hold the bowl on.

Not the kind that has a precision fit of the rim into a groove or bevel and "snaps" on.

 

[Doug Freeman]

You forgot an option - direct thread. I tried jaw mounted and too many times they did not run perfectly true when I mounted them. I made some that thread directly on the spindle (and reference against the bearing OD race like a chuck or insert) and they always run perfectly true.

 

[Sam Fleisher]

You forgot an option - direct thread. I tried jaw mounted and too many times they did not run perfectly true when I mounted them. I made some that thread directly on the spindle (and reference against the bearing OD race like a chuck or insert) and they always run perfectly true.

I like leaving my chuck on the lathe as much as possible. Putting a jam chuck in the o'donnell jaws allows me to finish turn the outside and then just turn the bowl around and do the inside.

That was what I was afraid of though by not being able to use the face plate rings that it wouldn't be as stable or repeatable with one or the other.

 

[Mark Mandell]

I use several jam chucks to make the caps for my ginger jars. I use a 4" faceplate and mount an 8/4 piece of hardwood (walnut, maple, cherry) that's screwed on from behind. I then turn it round and put a recess in the face. The cap stock is then jammed/centered. The ts is removed and the cap is hot glued. The interior is hollowed to matck the jar's lip. The cap is removed from the chuck and remounted, again with hot glue and the top 2 thirds are turned. Lastly the cap is removed, put on the jar, and turned to meet the jars shape.

 

[Doug Freeman]

I like leaving my chuck on the lathe as much as possible. Putting a jam chuck in the o'donnell jaws allows me to finish turn the outside and then just turn the bowl around and do the inside.

That was what I was afraid of though by not being able to use the face plate rings that it wouldn't be as stable or repeatable with one or the other.

I assume for dried 2 turn bowls. The bowl ID is warped, so “0” runout of the friction chuck is not required. You may find fitting them in the jaws acceptable.

I prefer to finish the OD after the bowl is turned around and in the jaws. I want concentric ID/OD at the rim. I had too many issues achieving that finishing the OD before chucking. With a lot of warp, when the ID is made round, the stress relief of removing a significant amount of wood causes warp in the OD.

 

[hockenbery]

I like leaving my chuck on the lathe as much as possible. Putting a jam chuck in the o'donnell jaws allows me to finish turn the outside and then just turn the bowl around and do the inside.

If your bowl is big enough you can use the bare jaws of the chuck. I do this when I remount a dried bowl.

Most any block of wood will do for a friction drive if the bowl is too small to fit over the bare jaws.
I use a lot of small cups with tenons for turning balls. These serve well as friction drives for small turnings.
Mine are mostly cherry, maple, mahogany, camphor

 

[Darryl Fective]

Early on, I would mess around with cole jaws, but I haven't touched them in years. I keep an assortment of glue blocks and cutoffs each with tenons for my 2" jaws. They have different diameters and roundness in profile and I grab what seems to be the appropriate fit. (or reshape if necessary) I also try to keep some scraps of leather close to slip in between. I find chiseling away the center nub to me much faster than swapping and setting up cole jaws.

 

[Ron Solfest]

I’ve turned hundreds of bowls with the pictured friction plate (I also have a couple others of different size). My standard process using dried wood is just to mount this plate in my Oneway jaws, pressure the piece on with the tailstock, and then turn the outside of the bowl and tenon. After I flip the bowl over into the jaws and turn the inside. If needing to turn a new tenon on a dried green blank I usually add another piece of rubber drawer liner loose over this drive plate before fitting the concave inside of the first-turned blank over it.

 

[Aaron Harris]

Interesting thread to me, as I'm about to have to flip my small 4-inch (ish) shaving bowl around to remove the tenon and finish the bottom, and it's too small for my big 20" Longworth chuck that I bought specifically for larger work on the 3520. Ron, I like your friction plate.

What I would like even better is if I can figure out a secure jam chuck that I can maybe hold it on after I remove the live-center/tailstock for some final light shaping cuts on the bottom. Something that won't mar the walnut or the epoxy finish I am putting on it. If anyone knows a good video for this process, I'd appreciate it. One of my summer "to-do" skills is to work on more versatile jam-chucking, glue-blocks, etc., when the standard methods won't work due to size or shape issues.

Maybe turn a recess for the od of the bowl into a disk like Ron's, and secure further? Rubber cement? Duct tape? Just thinking out loud here, but if I can solve this quandary, I feel like the world of smaller turnings opens up.

 

[Richard Coers]

I use a vacuum chuck to friction drive. Absolutely don't use drawer liner. Some of that stuff has a release agent on it yet and can put like an oil mark inside the bowl.

 

[Sam Fleisher]

I use a vacuum chuck to friction drive. Absolutely don't use drawer liner. Some of that stuff has a release agent on it yet and can put like an oil mark inside the bowl.

I'm making my vacuum chucks out of pvc couplers. What's the word on those rubber chucky seals they sell for those? Or the rubber chuckies for the different brands sold?

 

[hockenbery]

I'm making my vacuum chucks out of pvc couplers. What's the word on those rubber chucky seals they sell for those? Or the rubber chuckies for the different brands sold?

Rubber chuckys work great.
Disclosure I was one of Don Doyle’s Guinea Pigs and tested a lot of his inventions Don was in our club and the founded the company. Don gave me a lot of stuff.

Fun foam works well on PVC. It eventually wears or get cut by the PVC so it will need replacement every 5 or so bowls
10 bowls would be a rarity.
If you don’t soften the edge of the pie with a gouge it can cut the foam on the first bowl.
A nicely rounded edge helps the foam last longer.

I use pvc chuck from 4” to 1.5”. Medium bowls to ornament parts.

 

[Richard Coers]

I was gifted some Oneway Vacuum chucks, so no engineering needed. The bigger ones have a lot of contact area and the foam lasts a long time.

 

[Sam Fleisher]

Rubber chuckys work great.
Disclosure I was one of Don Doyle’s Guinea Pigs and tested a lot of his inventions Don was in our club and the founded the company. Don gave me a lot of stuff.

Fun foam works well on PVC. It eventually wears or get cut by the PVC so it will need replacement every 5 or so bowls
10 bowls would be a rarity.
If you don’t soften the edge of the pie with a gouge it can cut the foam on the first bowl.
A nicely rounded edge helps the foam last longer.

I use pvc chuck from 4” to 1.5”. Medium bowls to ornament parts.

Apparently Don Doyle is a one man operation?

I sent an email the other night pretty late my time. Not expecting an answer until the next day and I got an email pretty quick saying he was eastern time and it was bed time, to call the next day.

I was like oops.. Although it did say to email anytime.

 

[hockenbery]

Apparently Don Doyle is a one man operation?

I sent an email the other night pretty late my time. Not expecting an answer until the next day and I got an email pretty quick saying he was eastern time and it was bed time, to call the next day.

I was like oops.. Although it did say to email anytime.

I think Don makes all the rubbery parts. The metal parts - he used to have someone else make them.
The rubber parts are all made to a hardness that works.

With the ball cups he worked on the right formula. Rejects were too hard and too spongy. Then just right that went into production.

 

[Ron Solfest]

…Absolutely don't use drawer liner. Some of that stuff has a release agent on it yet and can put like an oil mark inside the bowl.

I might have mislabeled it, the product I use is sold as tool drawer liners (1/8” checkerboard rubber, no adhesive on it. I’ve used 3M spray cement, double sided tape, among others to adhere it to the plate).

 

[Ron Solfest]

…Maybe turn a recess for the od of the bowl into a disk like Ron's, and secure further? Rubber cement? Duct tape? Just thinking out loud here, but if I can solve this quandary, I feel like the world of smaller turnings opens up.

I think you could drive with a friction plate (or better even if you dish it somewhat) if you added stretch-tape to help secure it. Or even just mount it to a flat disk with double-stick tape. I’d recommend taking light cuts and do any real tool work while you still have the tailstock engaged (even if down to ~3/32” spindle), once you remove the tailstock you’d have to be very careful to do much more than sanding I suspect.

 

[Ben Hammock]

I use 1/4"hobby foam from Hobby Lobby on friction plate. When you apply pressure from the tail stock the turned piece will press into the foam so it holds very well.

 

[Tom Gall]

Fun foam works well on PVC. It eventually wears or get cut by the PVC so it will need replacement every 5 or so bowls
A nicely rounded edge helps the foam last longer.

If you add a ring of wood or MDF (I prefer PVC foam board - non-porous) and turn the surface round your "Foamies" will last forever - almost !!! They can sometimes be used without a seal but a thin (1/16") "Foamie" will avoid any possible scratches and compensate for any minor warpage.

 

[Sam Fleisher]

I saw somewhere that someone had split some surgical tubing (slingshot rubber) and glued that around the rim. Bad idea?

Does your smaller chuck have much holding power? That's what I was trying to ask the rubber chucky guy the other day whether it was better to use a reducer adapter so you would have a bigger chamber or use a piece of pvc pipe with a coupler on the end.

Also what's the hardness of the pvc foam? I've never dealt with it before.

 

[Tom Gall]

I saw somewhere that someone had split some surgical tubing (slingshot rubber) and glued that around the rim. Bad idea?

Will work in a pinch - but I wouldn't do it. Too elastic and basically will just conform to the edge on the PVC coupling ... similar to what Al H. was talking about with the Foamies. There is also the problem of getting a good seam/joint which is a source for leakage.

 

[Sam Fleisher]

Will work in a pinch - but I wouldn't do it. Too elastic and basically will just conform to the edge on the PVC coupling ... similar to what Al H. was talking about with the Foamies. There is also the problem of getting a good seam/joint which is a source for leakage.

I'm still waiting on my pump to get here from frugal. I guess I'm just not realizing the force that you can get from a vacuum chuck that it will cut through the foam seal pretty quick?

 

[Tom Gall]

I saw somewhere that someone had split some surgical tubing (slingshot rubber) and glued that around the rim. Bad idea?

Does your smaller chuck have much holding power? That's what I was trying to ask the rubber chucky guy the other day whether it was better to use a reducer adapter so you would have a bigger chamber or use a piece of pvc pipe with a coupler on the end.

Also what's the hardness of the pvc foam? I've never dealt with it before.

I assume the question is for me. The smaller the surface area (opening) the less holding power. As the surface area increases the holding power increases almost exponentially ... not really but will seem that way. Small chucks for small items.

The foam is very rigid and is closed cell material. It turns easily but messy like other non wood products. You can also use scraps of some plasticized deck material. Here is one link for the PVC Foam Board.

3/4 X 12 X 12 Cellular PVC Trim Board Synthetic Wood Plastic Sheet Outdoor Grade Palight White Smooth/Smooth

Love This : 3/4 X 12 X 12 Cellular PVC Trim Board Synthetic Wood Plastic Sheet Outdoor Grade Palight White Smooth/Smooth

freckleface.com

 

[hockenbery]

I saw somewhere that someone had split some surgical tubing (slingshot rubber) and glued that around the rim. Bad idea?

Does your smaller chuck have much holding power? That's what I was trying to ask the rubber chucky guy the other day whether it was better to use a reducer adapter so you would have a bigger chamber or use a piece of pvc pipe with a coupler on the end.

Also what's the hardness of the pvc foam? I've never dealt with it before.

The small diameters will hold a disc, box top, I wouldn’t put an 8” bowl on a 2” vacuum chuck.
I would use a 2” vacuum on a 4” disc.

I step mine down from 4” so I can use the same connection to the lathe. I just put couplings together no glue.

I think the diameter determines the holding power not the volume.
A flat disc has a huge holding power on a large diameter rim.

The gasket material is a variable. If it is too stiff it will leak on slightly our of round objects.
If it has a lot of cushion it will seal out of round but produce a spongy support for cutting.

If I don’t get a good seal I add a ring of foam and let the vacuum hold it in place.

 

[Dave Landers]

I have rubber chuckys on pvc. But I rarely get a good seal, so I always add a ring of foam.

 

[Doug Freeman]

As to holding force, its a simple eq: F=PA,
pressure x area of the opening, area = pir^2, thats pi x radius squared. The pressure is the amount of vacuum you generate, depends how your gauge reads for how to calculate.

A 2” opening is 3.1416 in^2 (pi).
A 4” opening is 12.57 in^2, 4x the force for the same vacuum amount. The force increase exponentially, as it is an exponential eq (r^2).

 

[Sam Fleisher]

I have rubber chuckys on pvc. But I rarely get a good seal, so I always add a ring of foam.

So maybe I should save my money? And just buy more foam sheets?

Bob leonard mentions using truck topper gasket in the instructions but after reading some of these replies would that be too soft and move a lot when using a gouge?

 

[Sam Fleisher]

As to holding force, its a simple eq: F=PA,
pressure x area of the opening, area = pir^2, thats pi x radius squared. The pressure is the amount of vacuum you generate, depends how your gauge reads for how to calculate.

A 2” opening is 3.1416 in^2 (pi).
A 4” opening is 12.57 in^2, 4x the force for the same vacuum amount. The force increase exponentially, as it is an exponential eq (r^2).

So in simple terms for my simple mind, having an adapter with a large diameter going down to a 2 inch for smaller items is not going to hold any better than just sticking a 2 inch coupler on a 2 inch pipe correct? Volume inside the chuck has no effect on force?

 

[hockenbery]

So in simple terms for my simple mind, having an adapter with a large diameter going down to a 2 inch for smaller items is not going to hold any better than just sticking a 2 inch coupler on a 2 inch pipe correct? Volume inside the chuck has no effect on force?

Correct. I use the adapters for convenience. On the same 4” base I can have 3, 2 or 1.5” openings.

 

[Dave Landers]

So maybe I should save my money? And just buy more foam sheets?

Foam sheets alone on pvc don't last. For me the rubber chuckys are worth it, even tho I need to supplement with a foam ring. I've probably used the same foam rings for over a year - if they were direct contact with the pvc I'd be remaking them for almost every bowl.

 

[Sam Fleisher]

Anybody use the angel wing seals from the oddnot guy? I found one video that cindy drozda made at some conference and the guy made it look like it works. Course like everything else there is a sale to be made.

 

[Sam Fleisher]

Foam sheets alone on pvc don't last. For me the rubber chuckys are worth it, even tho I need to supplement with a foam ring. I've probably used the same foam rings for over a year - if they were direct contact with the pvc I'd be remaking them for almost every bowl.

How hard are the rubber chuckies? I was just assuming they might be softer to be able to get a good seal? Something along the lines of a silicone seal. But they aren't?

 

[Dave Landers]

How hard are the rubber chuckies? I was just assuming they might be softer to be able to get a good seal? Something along the lines of a silicone seal. But they aren't?

I think they're supposed to seal, and I hear some (most?) folks are successful with them by themselves. I seem to remember they worked better when I first got them - maybe mine have stiffened up since I got them in 2019. I still think they're worth it. Works much better than when I tried taping foam bits on the PVC.
The craft foam is only like 1/16" thick so just enough to make a seal without really affecting the balance of the piece (but too thin to use alone on something hard like pvc). I have donuts of the stuff in a few sizes, just place it between the chuck and the wood.

 

[Gerald Lawrence]

I use craft foam and have at times just added another layer. It is very easy to change , just scrape off the odd and stick on a new one.

 

[Tom Gall]

So in simple terms for my simple mind, having an adapter with a large diameter going down to a 2 inch for smaller items is not going to hold any better than just sticking a 2 inch coupler on a 2 inch pipe correct? Volume inside the chuck has no effect on force?

Correct.

As to holding force, its a simple eq: F=PA,
pressure x area of the opening, area = pir^2, thats pi x radius squared. The pressure is the amount of vacuum you generate, depends how your gauge reads for how to calculate.

A 2” opening is 3.1416 in^2 (pi).
A 4” opening is 12.57 in^2, 4x the force for the same vacuum amount. The force increase exponentially, as it is an exponential eq (r^2).

What you said! I'm not good at this kind of math - but it looks like that just determines the surface area. The reason a vacuum chuck works is the amount of atmospheric air pressure on the piece - pressing against the chuck. At sea level the atmospheric air pressure is about 14.7 lbs. psi. Therefore, using Doug's 4" example approx. 185 lbs. of pressure is holding the piece on the chuck. Of course, this doesn't take into account your altitude where you live, porosity of the wood, leakage in the system, etc.

 

[Charles Cadenhead]

Rubber Chucky makes a whole line of friction chucks if you don't want to make your own.

EDIT: Just saw the rubber chucky comments. I'll post a picture of mine. I really like them. They're hard enough they don't fall apart but soft enough that they don't damage your bowl.

 

[Sam Fleisher]

Rubber Chucky makes a whole line of friction chucks if you don't want to make your own.

EDIT: Just saw the rubber chucky comments. I'll post a picture of mine. I really like them. They're hard enough they don't fall apart but soft enough that they don't damage your bowl.

Does the bowl move around any when you turn the tenon off if you were to do that?

 

[Tom Lucas]

I use the craft foam wrapped across the face of PVC adapters. The edges on adapters are more rounded than a simple piece of cut pipe, thus, less prone to cutting the foam. The foam is taped using electric tape on the outside, and a snap ring made from a cut piece of appropriately sized pvc pipe holds the inside. I can get 5 or 6 pieces turned before replacing the craft foam. I've thought about buying the rubber chucky's but haven't pulled the trigger just yet. Hard to go that route when the foam works good enough for about a Nichol a work piece.

 

[Sam Fleisher]

I use the craft foam wrapped across the face of PVC adapters. The edges on adapters are more rounded than a simple piece of cut pipe, thus, less prone to cutting the foam. The foam is taped using electric tape on the outside, and a snap ring made from a cut piece of appropriately sized pvc pipe holds the inside. I can get 5 or 6 pieces turned before replacing the craft foam. I've thought about buying the rubber chucky's but haven't pulled the trigger just yet. Hard to go that route when the foam works good enough for about a Nichol a work piece.

I like that idea of a ring inside to hold it.

 

[Tom Lucas]

I like that idea of a ring inside to hold it.

I can't take credit for that. Not my idea. A fellow turner on here (and grizzly owner as I recall) posted his and I just copied it. It works great, BTW. holds the foam tight to rim and makes changing easy. Just use the pipe size intended for use with the coupling, cut a tiny section out on the bandsaw leaving a gap of about 1/8" and it'll snap into place over the foam. I started with narrow cuts, gradually widening the gap until they fit nicely. No gluing. Just have to keep solvents off the electrical tape.