Button jaws; Is DIY possible ?

[Rhossydd]

Whilst I like making decent sized bowls and platters, one thing I've struggled with over the years is finishing the bases to remove signs of manufacture. I really don't like leaving the sockets needed for my chuck, plugging screw holes or worse sticking on felt bases.
I've used jam chucks occasionally, but they can work out expensive when they can't be re-used for other projects.
I've also made custom wooden jaws for my Henry Taylor Master Chuck too, but again the limited range of adjustment for this particular chuck can make it an expensive choice if they can't be reused.

I've recently seen the button jaws for the Axminster chucks:
http://www.axminster.co.uk/axminster-button-jaws
These look to be a great solution, but would involve a very substantial and unacceptable investment (new chuck, jaws, button jaws = £500+)

Has anyone tried to make anything like these button jaws themselves ?
My HTMC has the provision to add wooden jaws, so could be adapted to take something similar. I've come down to four propositions:

1. Making a set of aluminium jaw plates to fit straight onto the HTMC. Say 4mm Al sheet turning a recess to fit onto the jaws and drilling and tapping holes for 'buttons' (made from softwood).
Problem ? 6mm might be too heavy, 4mm might flex a little ? maybe a bit heavy.
Advantage: Durable and long lasting.

2. Perspex. Same as above, but with 6mm Perspex sheet.
Problem ? Perspex might be brittle and risk a nasty shattering event, plus any drilled and tapped holes for buttons wouldn't be so durable as Al.
Advantage: Durable and light weight.

3. 10mm MDF. Would need plates to mount onto the jaws, which might add flex in the whole system. Adding buttons with just woodscrews, so less reusable, but much cheaper.

4. Plywood. As per the MDF option, but possibly more rigid ?

I'll reiterate that this is just to finish the backs of bowls and platters, so shouldn't be subject to big loads. For those that don't know the HTMC it doesn't have the range of movement of modern four jaw chucks, so there'd need to be a lot of tapped holes for button mounting.

Anyone care to offer any thoughts on these strategies ?

 

[Spindle]

Hi

It has been done many times - I'd suggest mounting MDF or ply jaws to your HTMC as the best option. As for threading the wood - use Tee nuts for durability.

Regards Mick

 

[Dalboy]

How about making a Longworth chuck

http://www.google.co.uk/url?sa=i&rc...WI5Jnv4aCbaBAn32fe9Kns-w&ust=1392638760002924

 

[Grahamshed]

Are you familiar with the Longworth chuck ? Would that do what you need ? If you search for it on youtube there are many build your own vids.

 

[woodfarmer]

You have to excuse my lack of finesse as I naturally over engineer things, but this is what I would do.
The instructions may include some removing and refitting of the bits depending on bowl shape and the amount of room you have.

Using your biggest faceplate, make it bigger by fitting 1 " thick ply on it so the wooden faceplate is as big as it can swing and has to be much bigger than your bowl.

Mount you bowl to the faceplate by holding it centralised using your tailstock.

depending on the shape of the bowl screw about four blocks of wood well away from the edge of the bowl.
(screw from the headstock end, not the tailstock end).

now cut four bits of wood about an inch or less thick and say inch and a half wide. long enough to span from the blocks of wood to somewhere on your bowl so they could clamp the bowl to the faceplate.

Now screw the wooden strips to the face plate at about the middle so one end rests on your wooden block, the other on a part of the bowl that can be used to press the bowl onto the face plate.

when the bowl is secure, screw several bits of wood to the faceplate with one side tight against the bowl rim to stop it moving side ways. also screw the ends of the strips onto the wooden blocks.

You might want to pad any wood bit where it touches the outside of the bowl on the locating blocks and the clamping strips.

This system wont work for some shapes and most natural edge bowls, However with natural edge bowls you can use wedges to position between the rim and faceplate to get near central. once all aligned screw the wedges to the faceplate. Most of the bits can be re-used.

hope that helps.

 

[Rhossydd]

How about making a Longworth chuck

Not sure if I've seen that before, but it's perfect. Thank you for that link. An afternoon's work and that will solve the problem very elegantly.

The only problem now is getting a spare faceplate for my old Tyme Avon, but I can always make my own.

 

[Deejay]

Afternoon all

The only problem now is getting a spare faceplate for my old Tyme Avon, but I can always make my own.

Why not turn a cylinder of hardwood, glue and screw it to the back of the chuck and mount it in the HT chuck?

Cheers

Dave

 

[nev]

post638823.html?hilit=home%20made%20cole%20jaws#p638823

post724683.html?hilit=home%20made%20cole%20jaws#p724683

 

[Rhossydd]

Why not turn a cylinder of hardwood, glue and screw it to the back of the chuck and mount it in the HT chuck?

It's certainly an option. However with something as large as this will end up, 500mm dia, keeping it as close to the headstock with the minimum possible of overhang will be very desirable for several reasons. It will also be useful to have it as a self contained assembly that fits straight on.

Just buying a new standard faceplate isn't possible though, they've long been discontinued. An added complication is that Tyme chose a very obscure thread 25mmx2 for the headstock, so most generic parts won't fit. You can't even seem to buy a nut this size from my searches on Google this afternoon. I only found one supplier that offered a tap this size (if I wanted to make my own from scratch) and that's on offer at a staggering £142 !
The best bet at the moment seems to be to use the only on-the-shelf part that will fit, a mini faceplate from Peter Childs for £20. At least if it's not fully up to the job I can weld on something more substantial to the front at a later date.

 

[Spindle]

Hi

You can easily get an M25 x 2 chuck thread adaptor and a faceplate to suit the M33 x 3.5 external thread.

Edited to ask if your HTMC has an adaptor that you could utilise?

Regards Mick

 

[Silverbirch]

How about making a Longworth chuck

Not sure if I've seen that before, but it's perfect. Thank you for that link. An afternoon's work and that will solve the problem very elegantly.

Best of luck with that, but I found when I tried the same, it didn`t provide a strong enough grip to use without tailstock support. Given that, a large disc of plywood with a bit of router mat for grip does the job just as well and is a lot less bother. My button jaws in a scroll chuck give a much better and more reliable grip if I need to remove the tailstock support (which I only do to remove the last little bit, which can`t be reached with the tailstock in place.)

Ian

 

[paulm]

How about making a Longworth chuck

Not sure if I've seen that before, but it's perfect. Thank you for that link. An afternoon's work and that will solve the problem very elegantly.

Best of luck with that, but I found when I tried the same, it didn`t provide a strong enough grip to use without tailstock support. Given that, a large disc of plywood with a bit of router mat for grip does the job just as well and is a lot less bother. My button jaws in a scroll chuck give a much better and more reliable grip if I need to remove the tailstock support (which I only do to remove the last little bit, which can`t be reached with the tailstock in place.)

Ian

I do the same as Ian most times, quick, easy and effective.

I have the option of button jaws too, on a dedicated chuck, but mostly use the plain mdf (in my case) disc as quicker and easier.

Just need to use the tailstock support with it (which helps with centering anyway), light cuts, slow speed, and face/head protection (although never had an incident to date).

If in doubt, try the simple approach first, it often works

Cheers, Paul

 

[Rhossydd]

Talk of tailstock support is all very well, but not an option on the Avon when turning large diameters as the headstock has to rotate 90 degs. away from the bed bars.
Here's a previous wip:

In this case for safety the bowl rest on the right is brought in to prevent the bowl escaping the jam chuck, but it hardly counts as support.

 

[Random Orbital Bob]

tag

 

[woodfarmer]

Why not turn a cylinder of hardwood, glue and screw it to the back of the chuck and mount it in the HT chuck?

It's certainly an option. However with something as large as this will end up, 500mm dia, keeping it as close to the headstock with the minimum possible of overhang will be very desirable for several reasons. It will also be useful to have it as a self contained assembly that fits straight on.

Just buying a new standard faceplate isn't possible though, they've long been discontinued. An added complication is that Tyme chose a very obscure thread 25mmx2 for the headstock, so most generic parts won't fit. You can't even seem to buy a nut this size from my searches on Google this afternoon. I only found one supplier that offered a tap this size (if I wanted to make my own from scratch) and that's on offer at a staggering £142 !
The best bet at the moment seems to be to use the only on-the-shelf part that will fit, a mini faceplate from Peter Childs for £20. At least if it's not fully up to the job I can weld on something more substantial to the front at a later date.

Yes I was equally shocked to find the price of a 33x3.5 mm tap. My lathe does not do metric. I think if you turn to 25mm and set that lathe to cut 12 TPI it will be pretty close.

 

[Paul Hannaby]

I have button jaws but to be honest, I never use them for reverse chucking a bowl because there are easier ways to do it. My usual method is just to use a piece of scrap wood in the chuck (which gets re-used many times) as a friction drive against the inside of the bowl and the bottom of the bowl is held against it with pressure from the tailstock. Some router mat and kitchen roll protects the finish inside the bowl and three or four different profiles cover most eventualities.

One of my larger wooden "mandrels" is also cut to fit three different sets of jaws so I don't even have to change chucks to use it.

This method also works for natural edge bowls, thin walled bowls and anything else you care to think of! The only place it won't work is when you don't have the option of tailstock support such as when outboard turning. but I rarely have to resort to that.

Total cost of this solution was £1 for the router mat from the pound shop!

 

[J-G]

My lathe does not do metric. I think if you turn to 25mm and set that lathe to cut 12 TPI it will be pretty close.

Sorry to pour water on that idea but 12tpi is 2.116mm pitch and is no where near 3mm.

Ooops!! - I mis-read the thread size.

All lathes that have screw-cutting ability can cut both metric and imperial threads - albeit an imperial machine would (generally) make a metric approximation - with a 127 tooth gear in the train metric will be accurate over a longer length.


JG

 

[chipmunk]

Try here for spindle taps...

http://www.toolpost.co.uk/pages/Chu...cessories/turning_accessories.html#SpindleTap

or here...

http://www.tracytools.com/taps-and-dies

...much cheaper than the ones you saw but these are all HCS.

I think you will struggle with anything other than very basic items for your Tyme Avon though - M25x2 is a rare thread size.
The Toolpost do a backplate for a Versachuck in this thread though.

HTH
Jon

 

[Rhossydd]

Just an update to show how things have progressed;

I've built my first Longworth chuck following the plans linked to above by Derek (Dalboy).

This shows the first finished article. A small one(280mm dia) to start off with that can be used over the lathe bed. Made with 12mm ply. It's currently attached to a small screw face plate with cs allen head bolts that locate into T nuts recessed into one plate of the Longworth chuck. This seems reliable and strong enough to allow the faceplate to used for other tasks and remounted as required.

I've just tried it for the first time and it's worked well. Being a bit cautious I would up the tail stock to provide some support and limit any damage if it all went wrong. You can see that getting hold of the correct bungs is proving tricky so far. In the absence good bungs/stoppers/pegs mine consist of multiple rubber washers. The rubber deforms out nicely when the bolts are tightened to hold the work piece pretty securely.

One needs to be very careful when in use as it's too easy to forget the rotating pain potential behind the chuck. So far I've avoided it, but I'm considering a clip on cover to prevent any accidents.
So far the rotating mechanism seems pretty stiff. I guess it's a case of getting the pegs loose enough not to hold, but not too loose to bind up. Maybe smoothing out (and lubricating PTFE ?) the rubbing surfaces of the plates will be worthwhile ? I didn't like the idea of drilling the ply for a tommy bar, but have made up a peg spanner to fit the adjusting holes to allow it all to be tightened.

Next will be a substantial larger(500mm) chuck to use with the headstock rotated. I'll use 6 pegs for that on a bigger faceplate, but it'll have to wait until I've used this one a bit more to see if there are any flaws to correct or improvements to be made.

Thanks for everyone's help

 

[Spindle]

You can see that getting hold of the correct bungs is proving tricky so far

Hi

Plenty of options here or search under images of rubber feet. Door stops are a larger option.

http://www.ebay.co.uk/bhp/small-rubber-feet

Regards Mick