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Holding 16mm dia knob tenon

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Jacob

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Making knobs and pegs. What is best way to hold a 16mm shaft tightly without squashing it, so I can finish them one at a time, after turning 4 to 6 of them at a time from one piece, production style.
3 jaw Jacob's chuck squashes them
I've got a Sorby Patriot chuck but not clear if any of their add-ons would do it.
I've knocked up a chuck - wood held in Sorby chuck, 16mm hole, saw cut through and jubilee clip to tighten. Works OK but it that the best I can get?
 
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scooby

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My first thought for a cheap option was the same as the last one you mentioned.
Other alternatives (most expensive to cheapest).
1. Collet chuck.
2. Record power Pin jaws.
3. Record Power pen jaws. Not sure how well they'd grip tbh. If you have enough material to leave a temporary long tenon, that'd help.
 

Tris

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Your wooden chuck sounds as good a solution as any to avoid marring the surface. Perhaps add another cut at 90° to the first to get a bit more compression.
I've seen people use non slip matting in pin jaws but i can't help thinking that would allow too much movement
 

Phil Pascoe

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Turn a cylinder a bit longer than say three knobs and mount it in your chuck. Mark off the overall lengths and the tenons, turn the first knob, remove the tailstock for the final finishing, turn the tenon and part off. Replace the tail centre and do the next one. You'll probably find you don't even need the tail support if you do only two or three at a time - if you can hollow a goblet without tail support you can turn a knob without it.
 

Jacob

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Turn a cylinder a bit longer than say three knobs and mount it in your chuck. Mark off the overall lengths and the tenons, turn the first knob, remove the tailstock for the final finishing, turn the tenon and part off. Replace the tail centre and do the next one. You'll probably find you don't even need the tail support if you do only two or three at a time - if you can hollow a goblet without tail support you can turn a knob without it.
Yes I'll try that next. But I'd like to do sets of 4 or 6 to get them the same. Maybe a cup shaped tail centre to hold the finished knob head whilst turning off the tenon?
First wood chuck was oak and too stiff to tighten with the jubilee clip. Now doing another with ash and a thinner design.
Does take time to set things up but I'm hoping to turn them out fast and effortlessly in the near future!
 

gregmcateer

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I agree with either of the suggestions and your addition of a cup shaped tail centre won't hurt. Just turn one from scrap to fit over your normal live tail centre. Lounge it with paper towel or friction mat if don't want to risk marking it.
 

Phil Pascoe

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If the knob is finished, hold it in your right hand and part it off with your left. If it's securely mounted in the chuck it's only a tiny bit of vibration to counter - you're already down to 16mm. Leave 2mm or 3mm spare where the tail centre touches, it'll not leave a hollow just a few fibres to sand off. No reason why you shouldn't do half a dozen at a time, it's just the further from the headstock you get the more careful you need to be.
 
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scooby

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I agree with either of the suggestions and your addition of a cup shaped tail centre won't hurt. Just turn one from scrap to fit over your normal live tail centre. Lounge it with paper towel or friction mat if don't want to risk marking it.
Good advice. I got one of Paul Howards cup centres a while ago and its been really useful for making not just cup centres for spheres.
The outcome is the same as Greg described (using a live centre). For me (being lazy) its easier as the bearings are 35mm so I can grab a bit of scrap wood and just drill a 35mm hole (I've got a kitchen unit hinge drill that is perfect).
 

Duncan A

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If I understand you rightly, you want to hold the tenon in a chuck to finish the knob.
I usually do this by making a cylinder to fit in the chuck jaws, drill down the centre to be a snug fit for your tenons. Remove the piece of wood from the lathe and cut fully or partially down the length of one side.
Remount in the chuck, centre it carefully, insert your tenon in the hole and tighten fully.
Slacken back slightly to remove the tenon , and move onto the next one.
If I've completely misunderstood - apologies!
 

Jacob

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If I understand you rightly, you want to hold the tenon in a chuck to finish the knob.
I usually do this by making a cylinder to fit in the chuck jaws, drill down the centre to be a snug fit for your tenons. Remove the piece of wood from the lathe and cut fully or partially down the length of one side.
Remount in the chuck, centre it carefully, insert your tenon in the hole and tighten fully.
Slacken back slightly to remove the tenon , and move onto the next one.
If I've completely misunderstood - apologies!
Understood! Sounds better than the jubilee clip. I'll have a go tomorrow morning. Thanks for that
Turning does involve a lot of detail about methods and tools. I've done it on and off for years but only a dabbler so I keep having to learn or relearn things.
 

Robbo3

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Turn a cylinder that tapers slightly with the larger end towards the headstock & with a tenon to be gripped in your chuck..
Drill or turn out the centre to match your knob tenon.
Cut 2 slots at right angles down the cylinder to just over the length of the tenon.
Turn a ring to go over the taper so that as you tap it on it tightens on the knob.
 

Adam Pinson

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For some thinner items, i sometimes use the 'forbidden' centre of my supernova 2 chuck, it's not ideal, but it works.
 

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