Thread: Vacuum chuck system build WIP

Looking forward to seeing this in action! If you want to try it on a bigger Lathe you can come over!

Originally Posted by chuck1

Looking forward to seeing this in action! If you want to try it on a bigger Lathe you can come over!

Actually, if you can organise the handwheel rotary adaptor part to suit one of your lathes and a vacuum chuck or two to suit your spindle thread, you'll be welcome to borrow it when I'm not using it. (My thread is 1" 10tpi.)
I can't remember, do any of your lathes have a vacuum fitting on the side of the headstock? That'd make it real easy. We could soon make an adaptor to suit my 1/4" BSP female fitting on the end of the hose.


This is a bit long-winded, but I wanted to cover as many points as possible, for any one else planning to build one:

I got side-tracked today and didn't get as far as I'd hoped, but I did get the vacuum access hole in the handwheel done, along with a bit of rounding on the edge to make it more handwheel-like. I'll reverse the other half tomorrow and round the corner to match. I still need to bore and thread the holes etc for clamping the halves together then.
The 45 degree elbow on the fitting is only temporary. I have a 90 degree one coming, to keep the hose further out of the way. (To stop it twisting with the rotation from drag in the bearings, I'm making a small bracket to mount on the end of the lathe bench, with a fitting to hold the hose in place.)
(And please ignore the crappy quality ply - it's all I can get hold of, short of buying the 10mm hobby stuff online.)

m. Vacuum access hole 1.JPG n. Vacuum access hole 2.JPG


I didn't mention earlier, but when I press the bearing assembly into place during final assembly, I'll push it most of the way home, then put a smear of epoxy around the outside of the last bit of the second bearing and press it the rest of the way in. Should stay in place.

Also, I was concerned about a vacuum leak down the thread of the handwheel, but found that when it's tightened there's a small recess at the base that will hold a 17mm ID, 2.5mm thick 'O' ring, so I've ordered a few. That takes care of the potential leak at that end.

For the other end, at the base of the vacuum chuck itself, I'll use Blu-Tak around the base of this first vacuum chuck, (if needed), each time I put it on, but for future ones I'll try to cut an 'O' ring groove at the base and buy some 'O' rings to suit.

To ensure that there are no leaks through the ply, I'm sealing all of the parts well with poly inside and out, and the vac chuck thread is sealed with 3 rounds of CA followed by re-tapping each time.

Just in case anyone's interested, here's the handwheel plan (for a Pop's Shed mini-lathe handwheel). I had to stray slightly from the dimensions shown. The ply halves ended up being 18mm and 36mm instead of 19 and 37.
(It says full-scale, but it's not any more - I resized & converted to jpg for the forum.)

a. Rotary Adaptor Design_50.JPG

Let me know what O rings you want the cheapest place is near my work and I'll grab them for you, they have a huge range of sizes
could you use Teflon gas Plumbing tape on the thread?

Originally Posted by chuck1

Let me know what O rings you want the cheapest place is near my work and I'll grab them for you, they have a huge range of sizes
could you use Teflon gas Plumbing tape on the thread?

Very kind of you to offer, Charlie, but it's OK - I ordered some for the handwheel seal on eBay last night, 17.2mm ID, 22mm OD, 2.4mm thick.

I thought about just using teflon tape, but it's a lot of messing around and more importantly, I thought it might make it a bit hard to get the handwheel or vac chuck off again, since they aren't tapered. I don't have a spindle lock, so have to be careful in that regard.

An 'o' ring can stay permanently on the handwheel end of the spindle, and I'll fit one into all of my vacuum chuck bases from now on. Not sure what diameter I'll need for that yet, but probably 1/8" thick to suit a parting tool groove. I'll make the groove just deep enough to partly compress the 'o' ring while still allowing the base of the chuck to seat firmly against the collar. Probably glue the 'o' ring in place in the groove.

Pity, I bought 2 rolls of teflon tape the other day, for putting together the brass fittings, but will probably never use it for anything else.

Cool I will pull up a chair and follow this one.

Hermit,

Very nice tutorial.

Thanks

Originally Posted by Christos

Cool I will pull up a chair and follow this one.

Welcome aboard Christos. Hopefully you won't have to hold your breath for too long.

Hermit,
Very nice tutorial.
Thanks

Thanks Paul. Not that I'd really call it a tutorial though. I hardly know what I'm doing. Despite that, so far so good. Let's just hope I don't have too many leaks to fix at the end.


I've been busy on my other projects, but have made a little more progress.
The mini sintered bronze filters arrived yesterday. One less thing I'm waiting for. They go on the inlets of the bleeder valves as shown, to keep dust out of the system.

ap. Mini sintered bronze filters.JPG aq. Bleeder filters fitted.JPG


I cut a neoprene gasket for the facewheel seal last night, too. Initially, it had me scratching my head about how to mark the circles for cutting out. Black pen on black neoprene doesn't work well. Then, a brainwave - I put my scalpel-style hobby knife into the compass instead of a pencil, then went around the outline lightly several times until right through. It worked a treat. I'll glue it in place when I finally assemble everything else. A little messy on the ID, but that's only because I used a blunt blade.

ar. Neoprene handwheel seal.JPG as. Handwheel seal fitted.JPG


I also got the holes drilled and tapped for the handwheel clamp studs and cut the studs. To avoid getting hit in the knuckles by the nuts, I recessed them fairly deeply, a couple of mm below the surface when tightened. I made a bit of a mess of the holes in the pic above, but filled the tearout with epoxy.

at. Handwheel studs.JPG


I'm just putting a few coats of poly on these parts now, then I can press the bearing in and fit the studs.
I'm still waiting on a last few odds and ends before I can assemble everything, but hopefully they won't take too much longer.

If anyone sees a better way of doing something, or a detail I've overlooked, please let me know.

Originally Posted by Hermit

...... I don't have a spindle lock, so have to be careful in that regard.

......

I came across this simple solution on a website the other day hidden in here

Other Lathes

Go to
http://home.comcast.net/~kvaughn65/spindle_stop_1.jpg
http://home.comcast.net/~kvaughn65/spindle_stop_2.jpg

Originally Posted by Mobyturns

I came across this simple solution on a website the other day hidden in here

Other Lathes

Go to
http://home.comcast.net/~kvaughn65/spindle_stop_1.jpg
http://home.comcast.net/~kvaughn65/spindle_stop_2.jpg

Thank you for that Moby. Not a bad idea, and it looks pretty easy to make. I'll have to see if I can come up with something similar.
I keep putting it off, but I'll regret that the next time the chuck gets stuck on the spindle. Last time, I clamped a 12" bar tightly in the largest chuck jaws then struck it sharply with the heel of my hand and it spun free. I don't like doing that, though. I'd hate to damage the chuck.

G'Day Steve, You are sure doing a top class job on the WIP c/w notes....well done sir, cheers, crowie

Originally Posted by Hermit

Thank you for that Moby. Not a bad idea, and it looks pretty easy to make. I'll have to see if I can come up with something similar.
I keep putting it off, but I'll regret that the next time the chuck gets stuck on the spindle. Last time, I clamped a 12" bar tightly in the largest chuck jaws then struck it sharply with the heel of my hand and it spun free. I don't like doing that, though. I'd hate to damage the chuck.

Depends upon the design of the head stock spindle, but sure better than destroying a flimsy indexing pin. The old woodfast's have a hex "nut" machined into them, so no problem at all.

Originally Posted by crowie

G'Day Steve, You are sure doing a top class job on the WIP c/w notes....well done sir, cheers, crowie

Hello Pete. Thank you for the kind comment. I haven't done a WIP of any sort for a while.
I hope someone finds it useful in future when doing similar.


Before continuing with the finishing, I decided to do a quick test-fit of all the handwheel parts, to make sure it would go together OK. No problems. It slides together beautifully. I can't wait for the last bits and pieces to arrive now. They're coming from Asia and the UK, though, so it might be a week or two.

Meantime, I can get the finish on. As you can probably see from the pics below, I'm coating the outside of each half with epoxy before the poly, to fill tearout and ensure there are no potential leaks through the crappy plywood. I haven't done the clamp ring yet, just the main body. The clamp ring doesn't need it, since it doesn't have to be airtight, but I want the finish to match. (It's gotta look pretty.) I'm also filling all visible cracks/defects the same way.

I've tapped for the studs, but to make sure they don't move I'll wait until I've got them in then dribble some thin CA down into the thread to wick in and lock the studs.

That's still a temporary vacuum fitting in the pics - I'll swap to a 90 degree elbow when it arrives.

au. Handwheel test-fit 1.jpg av. Handwheel test-fit 2.jpg aw. Handwheel test-fit 3.jpg


I'm waiting on some 11mm spring-type hose clips, too, along with a set of four 21mm castors so I don't have to lift the main unit to move it.

Hi Hermit and all I will be following also just came across you're thread. I am enjoying the build it's looking very good so far, you're description and WIP photo's are great clear and defined.(keep up the good work we will be watching)
Regards Rod.