Does This Look Right?

[custard]

I'm only an occasional turner, and then only spindle stuff, so basically I'm pretty clueless.

I'm trying to fit a Jacobs Chuck to my 2MT lathe. This what it looks like,

Even though it feels solid enough it seems to stick out past the headstock quite a ways. Does this look right to you or should I be looking for a way of somehow removing that 1 1/4" 8TPI thread that my usual Nova chuck mounts on?

Thanks!

 

[Random Orbital Bob]

No that's OK Custard assuming the job isn't too heavy....the MT2 spindle and bearings can take a heavy load. Just be very wary of the Jacobs chuck rattling loose while turning as they have a tendency to do that. Usual solution is to place the tool rest in such a way that the end of it forms a barrier to the end of the chuck so if it does come loose it hits the toolrest first and the morse taper cant actually exit the headstock.

 

[Dalboy]

What Bob said also some people also have a threaded rod in the back of the morse taper fitted to the chuck and it passes through the hole and a nut is fitted which stops any chance of the chuck working loose

 

[Grahamshed]

It does, of course, depend on what you are trying to do. For many functions the jacobs chuck goes in the tailstock.

 

[monkeybiter]

some people also have a threaded rod in the back of the morse taper fitted to the chuck and it passes through the hole and a nut is fitted which stops any chance of the chuck working loose

A draw bar through the spindle is a good idea if the tapered shaft on the chuck has a tapped hole to take it. Depending on what you're turning you may also be able to use the tailstock, perhaps with an appropriately shaped wooden insert to gently keep the chuck in place.

Also, if possible, try to keep your direction of cutting from right to left, to minimise 'extraction forces'.

Alternatively can you hold the Jacob's chuck in your larger woodholding chuck? This wood be a more secure method if possible.

 

[custard]

Thank you all.

Some ingenious comments there. You turners certainly are a cunning bunch!

 

[CHJ]

Thank you all.

Some ingenious comments there. You turners certainly are a cunning bunch!

Not really, most just have a strong aversion to high speed hunks of heavy metal flying about in the same vicinity.

Operating a Morse taper driven device in a manner that does not keep it engaged with axial pressure, as it does in a pillar drill, is a definite no-no, should one be needed to hold small diameter components for turning without tailstock pressure it's essential for safety reasons to fit one with a Drawbar facility as already mentioned.

You will see comments from some folks that it will just loose drive and slide out, if you are lucky then it may, if it decides to start swinging off centre, as any tool forces may encourage, the centrifugal forces will rabidly increase its swing radius and even just coming into contact with a tool post at high revs can be very interesting experience.

 

[woodpig]

Most drill chucks fit to a Morse taper arbor with either a Jacobs or B series taper. Whilst the arbor itself can be secured to the spindle with a draw bar the chuck still sits unsecured on a short taper. Drill chucks are not designed to take side loads. Some drill chucks have a threaded body though and can in theory take light side loads if the arbor is secured with a draw bar. I've seen a drill chuck drop off a Jacobs taper so be careful how you use it.

 

[custard]

Operating a Morse taper driven device in a manner that does not keep it engaged with axial pressure, as it does in a pillar drill, is a definite no-no, should one be needed to hold small diameter components for turning without tailstock pressure it's essential for safety reasons to fit one with a Drawbar facility as already mentioned.

Makes sense.

It's for turning Shaker style drawer pulls. I usually make up several months supply at a time like this,

Because they're such small items they end up uncomfortably close to the four jaw chuck that I use to grip the spigot on each drawer pull. I was hoping a Jacobs chuck would give a safer method of work holding. The largest drawer pull is a 30mm long with a 30mm diameter and a 12mm diameter spigot, the smallest is 18mm x 18mm with a 10mm spigot. Most are in Cherry or Maple, with a few in Rosewood or Ebony.

Are there any other suggestions for work holding?

 

[Random Orbital Bob]

You're travelling the same road as I did when I started turning the stems for ornamental apples here Custard. I was using reject ebony guitar finger boards bandsawn into 11mm square "pegs" which I subsequently turn into tapering circular apple "stems" which get glued into the final product.

The challenge was how to hold them with no tailstock support and without doing damage to one's fingers in a large and cumbersome chuck.

I have used two methods with success:

1) A Jacobs chuck in the headstock morse taper exactly as you describe. In my case, I position the toolrest parallel to the spindle axis ie along the length of the ebony peg to be turned and leave the left hand side of the toolrest about 5mm from the front of the Jacobs chuck jaws. That way, if it does come loose it wont travel far from the headstock before butting against the toolrest. It's actually happened at least 5 times over many many apples and it's never caused any drama. Usually, I spot it the moment it starts to come loose as the sound changes. Switch the lathe off and pelt it with a rubber mallet to seat it in the headstock MT better. Also if you can pinch it with the tailstock until right at the last minute when you turn the very end, do that too.

2) Using Pin jaws in a regular 4 jaw chuck. Obviously, your pin jaws need to specified to the diameter (or take square stock diagonally if you get my drift) of the knobs you're turning.

I accept that my Jacobs chuck method has some theoretical risks but I'm comfortable with them and minimise them by using the following: Sharp tools, light passes; keep pressure in line with the spindle access as much as possible and I also cut into the chuck rather than away from. I also tend to use a skew which is a light pressure tool and in the correct axis and the big one....pinch with the tailstock for as long as you can.

 

[Random Orbital Bob]

Custard...it does also occur to me that if you like I'll do them for you

 

[woodbrains]

Hello,

if you dont mind spending a bit on a better solution, Axminster do a very nice chuck for just your sort of job. The Axminster junior chuck, which you can get with the right thread for your spindle nose, so no danger it ever coming loose. they use collets for gripping dowel. i just got one for my new lathe (I had one for many years for my old lathe precisely for turning door puls) for £44 with 3 collets.

Mike.

 

[J-G]

I would also recommend a Collet Chuck and the only thing wrong with the Axminster solution is the cost of extra collets - they are double the cost of the same item bought elsewhere.

ArcEuroTrade do both MT2 (for drawbar) and backplate versions and their collets are £5.57.

Personally, I would select the ER32 version, this gives a range from 2 to 20 mm whereas the Axi offering of ER20 will handle only up to 13 mm.

 

[custard]

Custard...it does also occur to me that if you like I'll do them for you

That's a fantastically generous offer Bob, but I'd like to lift my lathe skills a bit by practising more spindle turning. I'm seeing that after many years in the wilderness spindle turned furniture is starting to make a comeback.

 

[custard]

The collet chuck solution looks ideal. But I can't see any compatible with a 1 1/4" x 8tpi spindle thread. I phoned Arc Euro Trade but they're closed today for staff training, I'll follow it up tomorrow. Thanks again, great suggestion!

 

[woodpig]

You can get ER collet chucks from China quite cheaply on eBay. The last one I bought was an ER20 which was under £9, the collets for it were about £1.95 each. ER32 is a good size but the collets cost nearer £5 or £6 each the last time I looked.

 

[custard]

Have I got this right, you're saying instead of a Jacobs chuck I could have a collet chuck on an MT2 and just pop that in the headstock?

Couple of questions,

-how do these collets tighten, how long a process is that, does the headstock rotation need locking off while the collet is being tightened/loosened?

-how much diameter range would each collet have?

 

[J-G]

Have I got this right, you're saying instead of a Jacobs chuck I could have a collet chuck on an MT2 and just pop that in the headstock?

Yes - for me an ideal solution. It reduces the 'overhang' (with respect to a Jacobs Chuck), is infinitely superior as far as running 'true' and doesn't have the possibility of letting go of the front taper (it doesn't have one!)

Couple of questions,

-how do these collets tighten,

The front 'Nut' is simply screwed on just as if it were a nut and bolt. On the ER32 it has 6 slots and you use a 'C' spanner. (Small C-Chucks are hex)

how long a process is that, does the headstock rotation need locking off while the collet is being tightened/loosened?

It depends on the absolute difference between the diameter of your work and the nominal collet size but we're talking seconds rather than minutes. Yes you do need to lock the spindle by some means or at least have some way of applying an 'opposing force', and I consider it imperative to use a draw-bar.

-how much diameter range would each collet have?

ER32 have a 1mm range above 4mm and 0.5mm below that. Smaller versions (ER11, ER16, ER20) have 0.5 over a bigger range.

I only have the ER32 but I've used it to make 'buttons' for a Snowman Cruet - ie. similar to your Shaker style draw pulls - from 2mm dia Ebony.

I doubt that you will find a back-plate with a 1¼ x 8 thread 'of-the-shelf' that's why I suggest the MT2/drawbar option.

 

[CHJ]

The collet chuck solution looks ideal. But I can't see any compatible with a 1 1/4" x 8tpi spindle thread. I phoned Arc Euro Trade but they're closed today for staff training, I'll follow it up tomorrow. Thanks again, great suggestion!

If you can get a collet chuck with a rear flange I've got a couple of spare 1-1/4" X 8 ISO backplates that it could be mounted on, the backplate has plenty of spare material on it to allow for machining a location recess.

 

[J-G]

Arc Euro do three Flange Type ER32 Chucks - 95, 100 and 125mm Dia - so with CJH's offer it comes down to your ability to accurately machine a 55, 72 or 95mm registration spigot with the back-plate on your spindle.