Screw Chuck

[narrowboater]

I am having trouble with the screwchuck I made to turn fruit.

Following the WIP written by Richard Findley, I made one by putting a screw through a dished offcut which I had turned to fit my chuck. With the screw almost through the wood I put some Araldite both under the head and on top of the head.

It works ok for a while but after turning a few pieces of fruit the Araldite fails when I am unscrewing the finished piece, any advice?

Is Araldite the thing to use?

Should I coat the screw thead beforehand?

Any help appreciated, I seem to spend almos as much time making chucks as making fruit.

Regards

Rod

 

[chipmunk]

Hi Rod,
If it's failing as you unscrew the fruit it doesn't sound as if the threads of the screw are biting into the offcut block because that action would be tightening the screw from the back. The normal problem with homemade screwchucks is the glue failing as you put the screwchuck into the fruit. How thick is your block and how long is the threaded part?

Perhaps try a thicker block and a screw with a longer threaded section and apply glue to the threaded section before the last few threads enter the block - that way you won't get araldite onto the screw threads that emerge from the front face.

HTH
Jon

 

[Happy amateur]

When I had that problem with a screw chuck I used a slotted screw and put a staple into the back of the chuck so that it sat in the slot.
It worked a treat.

Fred

 

[Richard Findley]

Hi Rod

Araldite should be fine. As a guide I use a 2" coach screw in a 1" thick block. Make sure the pilot hole is fairly tight, so you have to screw the screw through it, get plenty of Araldite on the part of the shaft/screw thread that will be in contact with the block, as well as the head.

My screw chucks usually last for a few months and they get some serious wear and tear. If you're stil struggling give me a shout and I'll knock one up for you, in fact I have just made a few to suit my "C" jaws on my Axminster chuck, so I've got a couple spare.

HTH

Richard

 

[Turn It In]

Hi Rod,
To add another suggestion to all the help you have already had my screw chucks utilise a piece of hard wood drilled to accept a 2 inch hardened self tapper with a No 2 pozi head. i screw one through from the back and when its 6mm or 1/4 inch from fully in I coat the threads with super glue and quickly screw it all the way home.
When i screw the apples or pears etc onto the screw I drive them in with a pozi screwdriver so as to preserve the glue.
I hope this suggestion may be helpful as they last me a long while.
Regards,
Ian

 

[narrowboater]

Thanks chaps, I think my wood blocks are a bit thin, about 20mm, I will try another one a bit thicker, I also have not been coating the thread with adhesive.

Richard thanks for the offer, I will have a go myself but I may pop over, I will PM.

Ta for the help!

Regards

Rod

 

[wallace]

The screw I like to use is the ones used for fixing corrugated steel sheets down. They have quite a coarse thread and a 8mm socket fits on the head. Works for me

 

[Aled Dafis]

Hi Rod

Araldite should be fine. As a guide I use a 2" coach screw in a 1" thick block. Make sure the pilot hole is fairly tight, so you have to screw the screw through it, get plenty of Araldite on the part of the shaft/screw thread that will be in contact with the block, as well as the head.

My screw chucks usually last for a few months and they get some serious wear and tear. If you're stil struggling give me a shout and I'll knock one up for you, in fact I have just made a few to suit my "C" jaws on my Axminster chuck, so I've got a couple spare.

HTH

Richard

Richard, this may be a little off topic but I've not had much luck with the Axminster "C" jaws, do you cut a shallow undercut for the "lip"? I had a Nova (Sorby Patriot) previously and I found that the simple dovetail profile gave a far better grip in compression mode.

Cheers
Aled

 

[Richard Findley]

Hi Aled

You're right, the "C" jaws are quite a misleading shape but once I got it worked out I find they work great and use them nearly all the time.

Forget about the lip and just cut a parallel 56mm spigot, no longer than 8mm otherwise you bottom out, them put a slight dovetail on it. I find this works a treat!

HTH

Richard

 

[Aled Dafis]

Hi Aled

You're right, the "C" jaws are quite a misleading shape but once I got it worked out I find they work great and use them nearly all the time.

Forget about the lip and just cut a parallel 56mm spigot, no longer than 8mm otherwise you bottom out, them put a slight dovetail on it. I find this works a treat!

HTH

Richard

Thanks, I'll have another go at it tonight.

Aled