Longworth chuck

[Chumley]

G'day all,

Been trying to get some bowls made that don't end up with chuck marks all over them. I've been meaning to make myself a longworth chuck - got all the bits and pieces, bolts, rubber thingys, wingnuts, etc. Had a bit of a go last Saturday using a document I found on the forum (sorry but I can't think of who's doc it was, but thanks Cliff for sending it my way).

My lathe has a 3/4" thread on the headstock, so I followed the advice in the doc and bought a couple of nuts that fit - figured I could make the arc on the chuck longer if I didn't use a faceplate. I asked the metal guy (looks wrong but you know what I mean) in the shop what to use to fix the nut to wood - he suggested liquid nails. Did that, left it for several hours, cut the back plate into a circle with a bandsaw, put the back plate on the lathe, stepped to one side (luckily) and turned it on. Then I went to the back of the garage and picked up the back plate minus the nut which was still on the lathe.

Ho hum. So I tried another go with super glue. This time the backplate stayed on the lathe with the nut, but there was a huge wobble in the rotation.

I do have a face plate but it's about 150mm across, so if I use that I'm going to restrict how far the holding bolts can travel in the arcs.

So I have 2 questions: Firstly, can anyone advise me on how best to fix a nut to the backplate (I was using mdf, but I could get some plywood if necessary) - and how to get it flat so that it doesn't wobble so much?

Secondly, if I can't get this chuck working properly I'd like to try using a jam chuck. I watched a video of someone making a temporary jam chuck - they had a metal faceplate attached to a thin disk of timber, that disk had something threaded sticking out in the centre - to which he attached another disk by just screwing it on the thread and cut the jam chuck out of that. I'm guessing you can simply use new 'second' disks as you need them. Question is... is the threaded thing in the centre of the first disk a screw (like a wood screw) or a bolt?

Cheers,
Adam

[Cliff Rogers]

Maybe try epoxy this time.

Did you look at how the others did it in the threads I listed in this post (http://www.woodworkforums.com/showpost.php?p=803595&postcount=3)?

[robutacion]

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:2tsup:
RBTCO

[thefixer]

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

[artme]

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

[tea lady]

Spend some money with Mr. Vicmarc and buy one of his Vacuum thingys.:):)
We not ALL made of money.:rolleyes:

[powderpost]

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

[TTIT]

I wouldn't be mucking around gluing the disks on :o- 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.

[thefixer]

I wouldn't be mucking around gluing the disks on :o- 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

[Chumley]

Maybe try epoxy this time.

Did you look at how the others did it in the threads I listed in this post (http://www.woodworkforums.com/showpost.php?p=803595&postcount=3)?


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

[Chumley]

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

[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 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.:rolleyes::D

(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.:D)

[DJ’s Timber]

- 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.

[madcraft]

I wouldn't be mucking around gluing the disks on :o- 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

[Chumley]

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

[hughie]

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?

Adam this is the way to go, I have done it on mine and its a cinch. Quick and easy, low cost and very effective. :U:2tsup::U:2tsup:

[robutacion]

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

The thing is Chumley, no one knows it all, you have no reason to feel "stupid" about this. Firstly, we have ideas that are very difficult to follow just by reading it, secondly, we have the terminology to deal with, thirdly, we got tools & accessories that we don't recognise, fourthly, not everyone is mechanically orientated and then, the simple fact that one can be a beginner on this issues (wood-turning), making Chinese a lot easier to understand...!:D so, don't despair, we all have been there...!:;:doh:

Cheers:2tsup:
RBTCO

[joe greiner]

...we all have been there...!:;:doh:

Cheers:2tsup:
RBTCO

Boyoboy! Have we ever!:-

Sometimes, my engineering background gets in front of my construction background, my tongue gets wrapped around my eyeteeth, and I can't see what I'm saying. It was gratifying to read your assessment, a day or so late, because I hadn't caught it in time. Do you know about Private Messaging? PMs can be posted on the forum, which sends an alert to the user via email. Such PM can ask the user to visit the thread where a question arose. The target user can then answer in the thread, or reply to the PM, whichever is appropriate. And all this keeps email addresses safe from spammers.

Epoxy is a more robust adhesive than CA (superglue) - less brittle. For many assemblies, including simple waste blocks, some re-truing of a flat surface may be needed. Also, if using a scroll chuck, mark the jaw numbers at the purchase locations on the workpiece or faceplate ring; manufacturing tolerances for the jaws can be cumulative, almost conspiratorial (Is that a real word? Hmmm. Yes it is.).

It seems you have things under control, with the sage advice given already. I can't count how much I've learned here. And I hope to continue, especially since I got a new compu-duh-r, which will be another steep learning curve to install.

Adam (Chumley), you give me too much credit for my bandsaw "knowledge;" I'm a babe in the woods there, too.

Cheers,
Joe

[TTIT]

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.Get yourself a copy of the Carbatec catalogue and study the turning section - that will help bring you up to speed on the gadgetry we all talk about here - nothing wrong with not knowing it all before you start this caper :; (have a bucket handy for the drool!:U)


...... Could you kindly post a pic?
Thanks,
Adam
No worries - needed some pics of this one for my website anyway :shrug: . I made the ring on this chuck from an old flange off something before I had owned a 'proper' faceplate ring but the principle is exactly the same. I've pictured the chuck with a Vicmark ring facing the way it would on your disks.

[Gil Jones]

Adam,
Here is another way, although I do like the faceplate ring idea very much. It is called a Donut Chuck, and I like how mine works. I used a flanged nut, and it is epoxied in a 32mm thick piece of Poplar, which is epoxied and screwed to the main (back) plate of the Donut chuck. The epoxy I use is a 5:1 mix, and is very strong. West System Epoxy is the brand, but I do not know if it is available in Australia. http://www.westsystem.com/ss/

Supposedly, it is available here > ATL Composites Pty Ltd, PO Box 2349, Southport, Queensland 4215, Australia, Phone: 61 0755631222 <link rel="File-List" href="file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/msoclip1/01/clip_filelist.xml"><!--[if gte mso 9]><xml> <o:OfficeDocumentSettings> <o:RelyOnVML/> <o:TargetScreenSize>1024x768</o:TargetScreenSize> </o:OfficeDocumentSettings> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:DoNotOptimizeForBrowser/> </w:WordDocument> </xml><![endif]--><style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue; text-decoration:underline; text-underline:single;} a:visited, span.MsoHyperlinkFollowed {color:purple; text-decoration:underline; text-underline:single;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} -->? </style>

Also at > Adhesive Technologies Ltd., PO Box 21169, Waitakere, Auckland 0612, New Zealand,
Phone: 64 98386961 <link rel="File-List" href="file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/msoclip1/01/clip_filelist.xml"><!--[if gte mso 9]><xml> <o:OfficeDocumentSettings> <o:RelyOnVML/> <o:TargetScreenSize>1024x768</o:TargetScreenSize> </o:OfficeDocumentSettings> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:DoNotOptimizeForBrowser/> </w:WordDocument> </xml><![endif]--><style> <!-- /* Font Definitions */ @font-face {font-family:&quot; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-alt:"Times New Roman"; mso-font-charset:0; mso-generic-font-family:roman; mso-font-format:other; mso-font-pitch:auto; mso-font-signature:0 0 0 0 0 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue; text-decoration:underline; text-underline:single;} a:visited, span.MsoHyperlinkFollowed {color:purple; text-decoration:underline; text-underline:single;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} -->? </style>

[kdm]

I know this is an old thread but I didn't want to start another one on this topic. I have just made a Longworth chuck using a nut to attach it to the headstock. The method I used to attach the back plate to the nut was to drill 6 holes into face of the nut and tap them for machine screws. The machine screws go through the back plate and into the nut.

One thing I would do differently next time would be to have a round spacer between the nut and the back plate, say 10mm thick. This could then be hot glued to the nut and the face of it trued up on the lathe before bolting the back plate in place. I trued up the face of the nut with a file which was much more time consuming.

[issatree]

Hi Chumley,
Weld your nut to a 2 - 3in. / 50 - 75mm. Washer. Put it back on the lathe. Either file it down or use a bowl gouge to true it up, & make a pencil mark, so as you can bore some holes to take the screws or small round headed bolts, so as to attach it to the Longworth. If you have trouble with marks on your work because of the Jaws, Richard Raffan Filed the pointy bits from the jaws, & so left no marks. Hope this also helps.
REGARDS,
ISSATREE.

[Calm]

Hi Chumley,
Weld your nut to a 2 - 3in. / 50 - 75mm. Washer. Put it back on the lathe. Either file it down or use a bowl gouge to true it up, & make a pencil mark, so as you can bore some holes to take the screws or small round headed bolts, so as to attach it to the Longworth. If you have trouble with marks on your work because of the Jaws, Richard Raffan Filed the pointy bits from the jaws, & so left no marks. Hope this also helps.
REGARDS,
ISSATREE.

Wouldnt the washer be as big as a face plate ring?

[Texian]

Adam (or whoever reading this ole thread),

Having made two Longworth chucks and used them to flatten segmented rings, I never use them on a solid piece of work. Much easier and usually more accurate to use a flat disc screwed to a dedicated face plate for use as a doughnut chuck as Gil showed, or simply a friction drive. Strongly suggest use of particle board or good quality plywoood rather than mdf for the "drive" plate. My solid pieces usually have a center point left in the end of the tenon. This aligns the piece on the drive plate. The tailstock holds the work against the plate as the tenon is turned down to a small nub. Some thin, rubber coated packing material provides friction between the disc and the work. Picture shows both doughnut and tailstock in place. The doughnut is cheap osb. Easy to make several sizes and pad edges with similar material to avoid damage to the work.

[Skew ChiDAMN!!]

One hint: if you make a donut chuck, buy a few looong coach-bolts of various lengths.

Mount with the heads on the working face and wing-nuts towards the headstock. This saves you from a LOT of painfully barked knuckles.

DAMHIKT.

[kdm]

I think all these techniques have their place. I find the Longworth chuck great for tidying up the bottom of small bowls. That incidentally is why I used nut to attach it to the headstock rather than bought or made up face plate - it can hold bowls (well eggcups or whatever) as small as 5cm across.

[turnerted]

Hi Chumly
My suggestion is similar to tea ladies post .Just glue a tenon on the back of your MDF disc to suit your scroll chuck . If its not dead centre you can easily true it up when you mount it . I used this system for my vacuum face plate although I took it a step further and incorporated a hollow tube which I turned up sos it neatly fits down the inside of my scroll chuck to minimise air leakage .

Ted