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View Full Version : Which chuck to fit 6" rotary table??



wiatroda
09-08-2011, 09:30 PM
I need some advice.
I've got 6" rotary table and I want to buy a chuck. I thought to buy 125mm one.
Shall I buy 4 jaws or 3 jaws self centering ?? Or maybe independent jaws??
Any help will be appreciated

Web Goblin
09-08-2011, 09:47 PM
I think I would get an independant 4 jaw. A little bit harder to setup but you will be able to do more with it, ie off centre work which could open up some interesting options for you.

Ian

wiatroda
09-08-2011, 10:05 PM
I think I would get an independant 4 jaw. A little bit harder to setup

That what I'm worrying about.
But what is a difference/application between self centering 4 and 3 jaw chuck?????

i2i
09-08-2011, 10:18 PM
get both chucks

Web Goblin
09-08-2011, 10:20 PM
A 3 jaw chuck I think is better for a self centering chuck. It will grip a wider selection of materials like hex bar which you cant grip well on a 4 jaw.

Ian

wiatroda
09-08-2011, 10:38 PM
get both chucks
I didn't say yet to my personal budget accountant I HAVE TO but one. When I say I need two this can mean starvation and sleeping with a dogs outside :heehee: . I replied to her today: Rotary table wasn't expensive 10 or 20 , but I forgotten exactly how much I paid :rofl:

Jonathan
09-08-2011, 10:48 PM
get both chucks

Agreed...

You mentioned self centering 4 jaw. The advantage of it is 4 jaws clamp the stock more firmly than 3. For a given clamping force you will mark the part less with the jaws as less pressure per jaw. Not being able to hold hexagons is annoying as holding nuts in the chuck is a good quick way to hold a bolt without marking the thread ... but you're not going to want to do that in a mill.

I have a 4 jaw independent 100mm and 3 jaw (125mm) for the rotary table.
Being able to centre a part in the 4 jaw chuck is not much of an advantage as you can tap the chuck into place on the rotary table.

A chuck with bolt holes in the front makes it a lot easier to mount.

wiatroda
09-08-2011, 10:56 PM
A chuck with bolt holes in the front makes it a lot easier to mount.
That's mandatory
I thought to buy from RDG http://www.rdgtools.co.uk/acatalog/LATHE_CHUCKS_BACKPLATES_SOFT_JAWS.html are they any good?

wiatroda
09-08-2011, 11:00 PM
The fact is my rotary table have 4 t-slots so it looks like 4 jaw chuck with 4 front mounting holes as well will be perfect couple

m_c
09-08-2011, 11:02 PM
You need to think about what you're planning on doing with the rotary table.
A 3 Jaw self-centreing will be better if you'll be doing lots of round/hex bits, but a 4 jaw independant does give you more flexiblity, however it will mean you become very proficient in the use of a dial gauge! I've never used a 4 jaw self centreing chuck, but it could be a good compromise.

Personally, I've not got any jaw chucks for either of my rotabs, and I've never missed having one for what I do with them. Most of the bits I do get held via T-nuts, however, I do have an expanding mandrel holder that fits in the rotab taper which is very handy.

Jonathan
09-08-2011, 11:05 PM
Yes it does all depend on what you want to do with it.


The fact is my rotary table have 4 t-slots so it looks like 4 jaw chuck with 4 front mounting holes as well will be perfect couple

True, but it's not really hard to make a backplate is it...

I have a 200mm 4-jaw self centring chuck on my lathe, TOS brand. It's very accurate, but that's probably not an issue on a rotary table.

wiatroda
09-08-2011, 11:09 PM
You need to think about what you're planning on doing with the rotary table.

The first job i need to do is to cut 12 tooth 3m htd pulley from steel bar so I'm thinking about holding a stock in a chuck. Another issue is to produce a cutter to cut 3m hdt profile. I searched internet but it looks like the only option is to make cutter myself

Jonathan
09-08-2011, 11:13 PM
Another issue is to produce a cutter to cut 3m hdt profile. I searched internet but it looks like the only option is to make cutter myself

That's what I did for XL pulleys ... but then that's only a trapezium.

Small ball nose cutter and several passes to get the right profile? Would take ages but if it's a one off why not?

P.S. I've got some 3m HTD pulleys if you're interested... I'll go and check what sizes.

wiatroda
09-08-2011, 11:14 PM
True, but it's not really hard to make a backplate is it...

I have a bit of 6mm steel plate in stock. Do you think is it thick enough ??

Jonathan
09-08-2011, 11:18 PM
I have a bit of 6mm steel plate in stock. Do you think is it thick enough ??

As long as you don't need to tap it more than M8 I should think so. If there's a fair few bolts then it can't bend much. If it was on a lathe you would want more.

wiatroda
09-08-2011, 11:25 PM
That's what I did for XL pulleys ... but then that's only a trapezium.
Small ball nose cutter and several passes to get the right profile? Would take ages but if it's a one off why not?

The profile for 3m looks like this
4331
What about to drill 12 holes 1.8 mm dia then turn it to proper outside size???? Eventually tweak corners a bit
Jonathan I have those pulleys, but I need something like shaft ending with a pulley on the end. The stock one are not any good, I tried:sad:

Jonathan
09-08-2011, 11:56 PM
That looks like the profile for the belt, not the pulley. There's generally a small difference.

I've seen pictures of it done by drilling, so I suppose it's worth a try. I can't think of any reason for the holes not to be accurate. I would use 1.9mm as you'll be a bit stuck if the cut-outs are too small and it does not fit.
You might be able to 'tweak' the corners well enough with a chamfer. Maybe put it in a lathe and spin whilst holding a piece of wet and dry to it.

John S
10-08-2011, 12:41 AM
Drill 12 holes 1.8mm dia on a 9.96 PCD.
Then turn the OD back down to 11mm and give it a stiff wire brush up.

4332

wiatroda
10-08-2011, 09:29 AM
I think I'll go for self center chuck and eventually in a future for independent jaws.
Thanks Jon for calculations to do pulley this way will save me hassle with producing a cutter. What's the program by the way????

John S
10-08-2011, 09:47 AM
Pulley generated in Gearotic,

www.gearotic.com

Then saved as 2D DXF, brought into CAD and the two circles added and dimensioned.