Jam Chucks

[Randall Houghton]

Is anyone using jam chucks? What kind of wood are you making them with.I've been experimenting with jam chucks but I'm having a hard time finding a wood that doesn't mar my turnings without being so soft that it doesn't hold well. Any suggestions?
Regards
Randy

[Roger Bell]

I use ordinary 3/4 mdf.

[Jason Clark2]

I use them all the time for boxes, hollow forms, peppermills. Generally I use them for rechucking to finish the bottoms and tend to make them out of whatever I have on hand: Mesquite, Box elder, Maple, Eucalyptus, Honey Locust, Ash, Poplar, Walnut, etc. I have very few problems with marring regardless of the species used.

Jason

[Gary Max]

I have a handfull of different shaped blocks that I keep handy. Mostly Sycamore and Lucust.

[Jeff Nicol]

Is anyone using jam chucks? What kind of wood are you making them with.I've been experimenting with jam chucks but I'm having a hard time finding a wood that doesn't mar my turnings without being so soft that it doesn't hold well. Any suggestions?
Regards
Randy
Randall, You should use something between the wood and the turned piece to stop the marring of the surface. We had Greg Haugen up a week or so ago from another turners group here in WI. He is the president of the club and he uses an old mouse pad from the computer as a gripping surface and a buffer bewtween the two surfaces. I will sometimes just use a piece of paper towl or I have a thin piece of silicone rubber sheet that I use a lot too. A jam chuck can be so many things but if you use one on the inside of a bowl round over the edges a bit so there are no sharpe edges touching the finished surface. The wood I use is what ever is handy.

Jeff

[Don Carter]

Randall:
I agree with Jeff. I use what wood is available, mostly pine for me. I got a bicycle tire inner tube (Wally World) and cut it up to use as the go-between. It works great. I have also used the Foamies from the same store.

All the best.

Don

[George Clark]

3/4 MDF covered with a piece of router mat from Grizzly ($8 for 24 x 36 mat)

[Ben Gastfriend]

I mostly use pine, and I hot glue some anti-skid drawer liner to the pine to protect the work. If you do go with some type of router mat or drawer liner, don't buy too much until you are sure it doesn't leave black skid marks on the wood. :eek:

[Scott Donley]

I use a 3 in. pvc coupler with a piece of mouse pad ca'd to it. Has worked great on anything larger than 3 inches.

[Bernie Weishapl]

I use any scrapes I have available with a piece of mouse pad glued on the end.

[Steve Schlumpf]

Randall - I use scrap pine and just insert a small piece of packing foam between the jam chuck and the turning.

[Ryan Baker]

I use whatever I have available, but mostly it is just pine. I usually only use paper towel for padding -- fold it over a few times but make sure there isn't a fold in the contact area. I've never had it leave a mark.

[Rasmus Petersen]

use them a lot! for all kinds of stuff... i make them from what is on hand, ues just about anything theese days :-) oak williow mapel pine azobe u name it..

[Art Kelly]

I use leftover OSB siding. I used MDF until one exploded (due to a lapse in judgement:o). Never did find one of the pieces. Surprisingly, the work sustained just one tiny ding which I left as a reminder. If the OSB ever explodes it'll probably take out the shop wall with it. It's really stiff and strong.

I used to use mouse pad pieces until I got a little catch and left about the equivalent of an NHRA burnout on the piece.

Now I use pieces of felt pad made for putting under furniture, etc. It sticks OK with its self-adhesive backing the first time. After that I use the thick spongy double-stick tape. HF has sheets of the felt about 4"x5".

Of course, I haven't had a catch since...

Art

[john taliaferro]

my tailstock is off so it moves as it rotates and marks things.

[Richard Madison]

Just for reference, for anyone not familiar with the use of a jam chuck, it is a piece screwed to a faceplate or held in a scroll chuck, typically used to reverse a workpiece on the lathe so that the bottom may be turned. The work is held against, or on, the jam chuck with the tailstock. Seldom is a piece actually "jammed" onto the "chuck" with no tailstock support. There are exceptions, of course. The jam chuck may be as simple as a flat disc, or have a turned recess or tenon which matches and centers the work. As mentioned, some form of thin padding or friction material is often placed between the chuck and the workpiece. Hope this is helpful to someone.

[Art Kelly]

Just for reference, for anyone not familiar with the use of a jam chuck, it is a piece screwed to a faceplate or held in a scroll chuck, typically used to reverse a workpiece on the lathe so that the bottom may be turned. [...] Hope this is helpful to someone.

Oops! I was thinking "compression" chuck. <CTL><ALT><DEL>:(

Art

[Roger Alexander]

I am like so many other turners and use what ever wood I have on hand for the jam chuck. But on the end I use a piece of old carpet padding between the two pieces of wood. So far I have not parked up the work. Has worked for me even on platters. Good luck and keep turning.

[Richard Madison]

That's ok Art. The 15-1/2" disc for my doughnut (compression?) chuck sometimes gets used for a jam chuck too. Has a piece of some kind of rubberized mesh packing material (dunno where I got it) taped to it that provides friction and protection. The disc is 3/4" particle board, but the doughnuts (several size holes) are 1/2" or 5/8" scrap osb with edges of the "holes" beveled, sanded, and padded with the same packing material. Very ugly but effective.

[Art Kelly]

Jam the work up against a scroll chuck. No interface needed.:cool:

[Randall Houghton]

Thanks for all the replies.Lots of useful information. I have a concern about padding the chuck in relation to how strong the grip would actually be. If you get a chance go to the woodworking channel,look under the videos,find the AAW videos and watch Soren Berger hollow a scoop while it's mounted in a jam chuck and tell me if you think that is possible with a padded jam chuck.
Regards
Randy

[Richard Madison]

Randy,
Have done a scoop in a true jam chuck (no tailstock support). If the chuck is smooth and well shaped, no padding is needed for protection. However, found that mine needed a couple pieces of 2-stick tape to hold the scoop securely. The tape also provided a small measure of padding effect. Maybe be done with thicker padding, but would be tricky to get the fit just right and hold the piece securely. One vote for skeptical on padding.

[Don Carter]

Randall:
I have made a bunch of the scoops as you describe and I make them from black walnut and the jam chuck of pine. If you make the scoop as round as possible then you can make the chuck fit with no padding. Problem is you have to make a new jam chuck each time unless you make the scoop exactly the same size.

All the best.

Don

[Wyatt Holm]

I use mdf, or particle board. I must be misunderstanding some of you, what do you need the padding for? I use padding when I use a tension drive, but not a jamb chuck.

[Don Carter]

When I turn the bottom of small lidded boxes, I do use something to cushion the jam chuck inside the box. Most times I have already put a finish on the inside and the cushion just helps from marring the finish. I have used the jaws of the scroll chuck to hold the box and when I do, I use wide rubber bands or some type of foam over the jaws. Is that technically a jam chuck?;)

All the best.

Don