Making a screw chuck

[maverick54]

After viewing the price of screw chucks I've decided to make my own. I'm thinking (but probably wrongly) that if I screw a piece of wood to my face plate and drill a hole in the middle I can then take it off again and simply put a screw in through the rear.

Is it that simple and if so what size/type of screw would I need? its for turning 35mm x 400mm sqare hard wood into 30mm x 400 round

 

[Spindle]

Hi

I essence what you are proposing is an existing practice, however if you are proposing to turn a disc 30mm thick with a 400mm diameter I would suggest that this is larger, (in diameter), than I would like to attempt with a screw chuck into less than 30mm of wood. I would mount the work direct to the faceplate with at least three screws.

If you mean to turn spindles 400mm long with a diameter of 30mm I suggest you turn them between centres.

Regards Mick

 

[graduate_owner]

You may need some method of stopping the screw from spinning around. I have an old Myford chuck which has a spigot with a threaded hole. A grub screw fits through this and locks onto a flat on the woodscrew to hold it firmly. In your case perhaps a section of your wood (on the face plate) could be turned down to form a spigot, and an epoxied nut countersunk into this could hold a grub screw. Then file or grind a flat on your screw. Your chuck could be made from several pieces of plywood glued up so as to give enough 'meat' for the spigot.

Might work?

Bear in mind the potential holding power of one screw is limited, and the new parallel thread screws are far better than the old woodscrew type. And finally bear in mind that end grain holding is less secure, so keep the wood down to a sensible size.

K

 

[monkeybiter]

I have done just that, as have many others; use the biggest screw [length and width] you can, make sure it is central, and in use support the work with the tailstock at least while turning to round, and as long as you practically can after that.

Even better cut the corners off first with the most appropriate saw available [bandsaw etc.]

 

[jpt]

My method of making a screw chuck http://www.woodturned.co.uk/html/screw_chuck.html

john

 

[Phil Pascoe]

Glue chucks?...

 

[maverick54]

Thanks guys, and yes its for spindle work. Just wondered if I needed a particular type of screw or if a normal wood screw would do the job. £32 to buy one on ebay - lot of money for a screw.

 

[Spindle]

Hi

Now I'm curious - why would you want to use a screw chuck to turn spindles as opposed to turning between centres?

Regards Mick

 

[CHJ]

I would not contemplate using a screw chuck for spindle work as a first choice, the majority of wood types will not give a good driving fix in end grain for heavy or interrupted cuts.

Two or Four Prong drive centre are the basic options or for maximum efficiency and usefulness a Stebcentre, but I guess the the latter is out on cost grounds.

 

[maverick54]

After reading the 2 posts above I'm obviously thinking this wrong. The reason I was going to use a screw chuck is I thought it would make less mess in the end as this will be on show for what I'm doing. I thought I'd just add a bit of filler to the screw hole after. If I used a drive spur I assumed it would make more of a mess to the end and I would have to cut it off after with a saw which I was hoping to avoid.

The item in question is a 6" mini butt to screw into the end of a snooker cue. I have the brass joint and thought it would make a nice little project to get me started.

 

[Spindle]

Hi

A normal four point drive centre does not leave much of a mark, a stebcentre leaves even less. If I were doing it though I'd cut the stock slightly over length so as I could part it off once finished - this will leave the ends perfectly square and well finished. Parting will leave a small 'pip' that is easily removed with a sharp knife or chisel.

Regards Mick

 

[CHJ]

As Mick says the norm is to produce the blank over length and part off/trim the component both ends, this allows for run-in/run-out turning waste and sizing checks.

If this is a terminal component then presentation is the key and I would think that drive centre and tail stock centre marks are best avoided.

 

[maverick54]

Thanks guys much wiser now and it all makes sense.

 

[Paul Hannaby]

Or, use a dead centre as the drive centre. All it leaves is a small indentation in the end, which can be turned away, filled or disguised some other way, depending what you are making.

If you haven't got a dead centre, use a live centre gripped in the chuck but obviously you need to grip the bit that would normally spin! :wink:

 

[Richard Findley]

Hi

Although it is usually not recommended to hold spindle work with a screw chuck - because in theory a screw will naturally hold better in side grain than end grain - I have found that in practice, with the right sized hole, it grips just fine.

I make a lot of walking sticks (about 1400 at the last count) which are on average finished to a max of 22mm diameter and around 845mm long. I use a home made screw chuck for these for 2 reasons:

1 A central pilot hole at one end is ideal for fixing the stick heads
2 It allows me to apply minimal pressure with the tailstock to avoid/minimise flex, vibration and chatter.

I use a 6mm coach screw and you can either fix it into a wooden block with epoxy and then hold in your chuck or faceplate as you suggest. Alternatively, if you have engineers style jaws on your chuck you can nip off the head with bolt croppers and simply hold it like that.

For the 6mm coach screw I drill a 3.5mm drill in Beech but it might need to be bigger in a denser wood.

HTH

Richard

 

[graduate_owner]

You could also try a pin chuck (again, not so good in end grain). I make these myself - just a piece of round steel with a flat ground off, and a suitable cut off nail for the pin. Practically no cost at all and really easy to make. I hold them in a 3-jaw metalworking chuck that fits my Myford. I don't know how it would compare with a screw chuck for your particular application.

K

 

[maverick54]

Thanks Richard, was thinking of having a go at walking canes after ive finished my first couple of projects. Have you posted any pics of any of your work. Would love to see some.

Regards
John