Sanding rule 345,234

[adrian]

When sanding a bowl clamped in your VM120 and new bowl jaws make sure your hand doesn't slip.
It brought back memories of the old school days when one particular teacher used to catch the back of your hand with the cane on the way back up.
At 8 revs per half second those 8 red projections on the jaws give you 64 of the not-so-best.
Is my maths ok? Who cares, it bloody smarts!!!! :eek: :eek: :eek: :eek: :mad:

[gatiep]

Use with care or get your thinking cap on, use a piece of inner tube cut through into a lucky band or even wrap a band held on with some velcro at the ends around the protrusions. There are many ways to make a chuck safe for sanding. The easiest is to concentrate on what your doing.......for the rest there is sore knuckles. :)

[smidsy]

Adrian,
I have those bowl jaws and they are a great bit of kit but they're only rated for 300rpm max so it's best to use them just for the areas of the bowl you can't get to with standard jaws - like the bottom of the bowl.

I finish the bowl completely, sanded and polished inside and out, then put the bowl in the bowl jaws (with a couple of layers of soft cloth between the jaws and the polished wood) so I can take off the chuck recess.

Cheers
Paul

[adrian]

Adrian,
I have those bowl jaws and they are a great bit of kit but they're only rated for 300rpm max so it's best to use them just for the areas of the bowl you can't get to with standard jaws - like the bottom of the bowl.

I finish the bowl completely, sanded and polished inside and out, then put the bowl in the bowl jaws (with a couple of layers of soft cloth between the jaws and the polished wood) so I can take off the chuck recess.

Cheers
Paul
They are brilliant aren't they. The only problem is that they are a real pain to get on and off for just one project.
I turn mostly green wood so I'm going to leave the chuck recesses on a few projects because the bases usually warp a bit anyway. Then I can do a few in one go.
I think you've got the VM100 jaws. I'm surprised that the speed rating is so different from the VM120 265mm jaws which are stamped as Max 1000rpm

[smidsy]

Adrian,
Apologies for leading you up the garden path - the jaws are rated for 1000rpm.
That's what happens when I do 5 things at once :o

They can be a pain to fit and remove, although the result is well worth it.

The main thing I have found that you need to be careful about with these is that they have enough weight & momentum to spin off the shaft when you shut the lathe down. Everything else I put on the lathe I just tighten by hand but the chuck and bowl jaws I tighten with the spanner and bar.

Cheers
Paul

[adrian]

I always use a hose on the dust extractor to clean the bench but you never realise how much you miss until that bugger starts spinning. It's like a propeller.

[smidsy]

I use an airhose for cleaning my lathe - although my friends can't work out why the lathe is clean enough to eat off yet the rest of the shed is a tip lol.

Before I got in to woodturning I flew R/C planes for 6 years - that is good training for turning because there's nothing like a knife sharp propeller spinning at 10 000 rpm to teach you where not to put your fingers.

Cheers
Paul

[rsser]

A cheap alternative to bowl jaws (aka Cole jaws) is to make up your own vac chuck - no flying knuckle cutters! There are designs on the web (assuming you have a hollow headstock shaft. Or Vicmarc make one themselves if you don't; for a 30 x 3.5 thread).

Positioning is quick if you leave a centre mark on the foot and line it up with the tail stock centre.

I'll post pikkies of mine if pple are interested. It's not pretty but it works ;-}

[adrian]

I was thinking of making a vac chuck but I've got so many things on the "one-of-these-days-I'm-going-to-make-one-of-those" list that I bought the bowl jaws instead.
Having that that, I would like to see a picture if you have one.

[rsser]

It's a 3/4" thick disc of MDF covered in foam-rubber and screwed to a faceplate. Into a hole in the centre of the disc is glued a length of 1/2" copper piper that runs through the spindle past the handwheel.

Into that end slots a bit of brass tube salvaged from a light fitting, with a grommet backed by a copper collar to make the seal. At the other end of the tube is a sealed bearing glued on over which the vac cleaner tube cuff sits, held on with a mini-okky strap. A couple of 1/8" holes are drilled in the cuff to allow some blow-by.

Voids can be covered with glad wrap or duct tape.

If I were doing it again I'd cover the face with neoprene for durability, and play around with doing without the copper tube by eg. using a washer between the face plate and spindle shoulder.

It's good for light cuts and sanding to finish a bowl foot, up to swing over bed size. Anything heavy or bigger and I use the Cole jaws but it's a pain positioning all those knuckle cutters. (Maybe there's a reason why they're red!).

Hope this helps.

[rsser]

Adrian,
I finish the bowl completely, sanded and polished inside and out, then put the bowl in the bowl jaws (with a couple of layers of soft cloth between the jaws and the polished wood) so I can take off the chuck recess.

Cheers
Paul

I can also recommend strips of router mat aka non-slip rubber mat (available from Clark Rubber down here cheaply). With an irregular bowl rim you can use them up to several layers thick to pack out the gap.

(I've also used a hex bit in an electric drill to tighten the jaw rubbers, but it chewed up the bit pretty quick and I was always paranoid about stripping the thread - it's only aluminium plate).