Thread: Longworth chuck

Maybe try epoxy this time.

Did you look at how the others did it in the threads I listed in this post?

Hi Chumley.

I don't thing that I am able to help you with the second question, as I don't know what thread you are referring to, so I can't comment but the first question, I can help you with. I just have done a 230mm plate for using on my old GMC lathe, as sanding machine using the big nut system glued on ply (some for MDF). This disks to work well, you have to get them balanced and into the right size, but turning it after the nut is strong to support the whole thing. I would recommend to start with a little oversize diameter 5 to 10mm if possible, as you will lose also a little bit on the thickness )to balance it right). The amount you will lose, depend solo upon the way and straightness that nut is glued to the board, and to achieve a good result I will recommend you to do this. Measure the diameter of the nut and by using a spade or forstner bit of that size, drill/recess the centre of the board where the nut is going to be glued, only a few millimetres deep (5mm max.). You can do this on the lathe if you can mount temporarily the board on it. This fit doesn't have to be perfect, but helps if is a neat fit (no movement). We are going to use Araldite 24 hours (stronger) but before we start mixing the glue, we need to make a round barrier to stop the glue to "sag" down, and exposing the nut. We need to achieve a reasonable wall of glue around the nut and at least up to half to 2/3 of the nut hight exposed. This "retaining wall" can be made of anything you want (plastic, metal or card board) I use often the empty toilet roll paper cylinder for these things, firstly because they are easy to install, they come out easy after the glue is dry (wetting it), as if you use other materials, you need to run a little bit of news paper inside, so that the glue stick to it. After you have the nut in the board recess, measure how far up you want the glue to go and cut the "barrier" to that hight. Use hot melting glue to fix it into place or if you don't have a hot glue gun, use tape to keep it there and seal it so the glue doesn't come out from the bottom. Make sure the bolt is clean of any oils or dirt and that the recess outer edge is clean of dust, etc. One of the secrets to make sure the glue doesn't separate from the board, is to use small nails, small screws, or a staple gun that will leave the staple half way out, on that area of the board around the nut and where the glue is going to go, (inside of the "barrier"). After that, you just need to mix the glue and pour it inside the barrier all around, until it reaches the barrier top. Use a small weight to keep the nut down, and let it dry. After that you mount it on the lathe and you turn it to the right diameter and "shave" cut until is totally balanced (straigh) both faces. I like to cut a hole straigh trough the board with the same size as the nut inside, so that the nut is not going to get pulled out by the forces of tightening the board on to the lathe simple threaded end. The board should lock on the nut outer face, and not on the end of the board, (back of the glued nut), if not drilled out.

I hope this can be of some help to you,
Good luck

Cheers
RBTCO

Hi Chumley

You could try turning up a piece of hardwood about 80 mm diameter and 30 mm thick. Bore a hole through it til it fits over the thread and then turn a recess so the nut fits snugly into it and epoxy the nut into place. Then screw and glue that to the rear plate of your longworth chuck with to nut facing the backplate. You should then be able to thread the longworth on firmly and centrally. Hope this makes sense to you.

Cheers
Shorty

Spend some money with Mr. Vicmarc and buy one of his Vacuum thingys.

Originally Posted by artme

Spend some money with Mr. Vicmarc and buy one of his Vacuum thingys.

We not ALL made of money.

I have built three longworth chucks, they are very good but not infallable. Would strongly urge you to have a small face plate welded to the nut and screw fix through the plate into the backing plate. Better still get an 80mm face plate to do the job. I found an 80mm plate will allow the longworth chuck to accept a very small diameter bowl. I also foung that six grooves is the best, any more leaves too little wood on the internal end of the grooves.
Hope this helps you out.
Jim

I wouldn't be mucking around gluing the disks on - asking for trouble. As Jim said, go for a small faceplate or better still, use a faceplate-ring which works a treat. They are cheaper than faceplates and you don't have to remove your chuck to use it which is always a good thing.
If you want to go this way, I can take a pic of mine for you to look at.

Originally Posted by TTIT

I wouldn't be mucking around gluing the disks on - asking for trouble. As Jim said, go for a small faceplate or better still, use a faceplate-ring which works a treat. They are cheaper than faceplates and you don't have to remove your chuck to use it which is always a good thing.
If you want to go this way, I can take a pic of mine for you to look at.

I think he has a GMC lathe TTIT . He says in his thread 3/4" thread therefore no 4 jaw scroll chuck.

Cheers
Shorty

Originally Posted by Cliff Rogers

Maybe try epoxy this time.

Did you look at how the others did it in the threads I listed in this post?

Yep, several times. But Joe was the only one to talk about how to actually attach the chuck to the lathe - I like Joe's posts and find them very useful (especially on the bandsaw forum), but I must admit I don't always understand them as I'm not really the engineering type.

The Garret Lambert article was the one I used as ref - he shows the nut, but doesn't say how he fixed it to the backplate.

I'll try again with epoxy - but now I know superglue works at a fixer, I only have to get the alignment right.

Cheers,
Adam

Wow, thanks for all the replies - got some good stuff here!

Robutacion and Fixer, great idea - I can even picture that in my mind - a smaller backplate with a hole inside which I glue the nut with plenty of grab as I can fill the space around the nut with glue and I can drill out the plate so the lathe bolt has further to go, then screw that smaller backplate onto the longworth backplate. Cool.

Artme and tealady, I made a deal with myself to try to get the most out of this first (he he) lathe without spending much money (which I don't have much of). I did buy some proper tools and a scroll chuck, but I'm trying to do everything else with what I have.

Powderpost and TTIT, I'd like to get this right if I can, after all, others' have done it, so why not me, and there's nothing much to cry about if it doesn't work. 6 grooves it is.

Thanks again everyone,
Adam

So you have got a scroll chuck? Then put a face plate ring on the back of the Longworth chuck, to hold with the chuck? I think you can get them from ye olde Carbatech. But the face plates themselves are only $50- $60 for the smaller sizes, so don't go mucking about tooooooo much. Epoxy is $15 bits of wood is ___, bug nut is _____, face plate ring is ____, petrol and running about is _____. Knowing the thing is not going to fly apart? Priceless.

(Although I do understand the "make it myself" impulse. There is something about knowing how things are done, and being able to if you needed to. We'll be valuable when society breaks down, civilization is destroyed and we have to build from scratch again. I can make cups and bowls from dirt out of the ground, so I won't be eaten.)

Originally Posted by Chumley

- but now I know superglue works at a fixer, I only have to get the alignment right.

Don't rely on Superglue alone to hold the nut, it will break off or weaken on the first shock or impact it receives.

You can use it to secure the nut to the board and then build an epoxy well around it to do the final secure hold on it.

Originally Posted by TTIT

I wouldn't be mucking around gluing the disks on - asking for trouble. As Jim said, go for a small faceplate or better still, use a faceplate-ring which works a treat. They are cheaper than faceplates and you don't have to remove your chuck to use it which is always a good thing.
If you want to go this way, I can take a pic of mine for you to look at.

Hi TTIT

I wouldn't mind seeing how yours looks

Originally Posted by tea lady

So you have got a scroll chuck? Then put a face plate ring on the back of the Longworth chuck, to hold with the chuck?

I never thought of doing that - how simple (feeling bit stupid at the moment) (actually feeling very stupid)!

TTIT, just realised you covered this also - didn't realise what a faceplate ring was when I read your earlier post - my apologies. Could you kindly post a pic?

Thanks,
Adam