Thread: Got any vaccum chuck ideas for this ?

You don't want a perfect vacuum seal... that burns out the vac's motor. Most commercial vac chucks have a pressure relief valve to prevent this... and home-made ones usually leak enough they don't need one. If you've got an old drum-type shop vacuum, you may be lucky and have the pressure relief built into the vac itself, which saves some headaches. (That's how mine is. [Phew!])

One method I've seen for connecting to the MC-xx headstocks (what you got) is to tap the inside bore to take a nitto or similar air-hose fitting. Then you can clip an airline on (the connection acting as a swivel) but connect it to a vacuum instead of a compressor. This tends to wear out the connectors, but if you have a few already lying around...

Another method I've seen is to fit a rubber seal around where the shaft comes through the headstock (on the inside of hatch that you've removed) and then fasten an old tin can to the outside of the hatch. Cut a hole in the end of the tin can to plug a hose from your vacuum, et voila! A "non-swivelling" connection.

I like this last idea, been meaning to follow it up myself, but I imagine it'd be a right headache trying get the rubber seal on the shaft to be a near air-tight fit.

Thanks skew. appreciate the help.

What are those nitto connectors again ? I've never used them. Well I might have, but never put a name to them. If there cheap enough maybe I could try that and replace when they wear out ???

I was hoping for a non-swivelling connection so there's no wearing tricky bits I've got to try and work out.....but I'm having trouble visualising how I can seal around the shaft when I've got a big pulley on it with a belt running off the side to a motor....maybe I'm missing something..... How about if I made a big woodern box that inclosed the entire motor, belt and runs up tight around the back end of the headstocks casting and seal it all up with something sticky, then plug a hose into the box......Would there be too much space in that box. Too much that it wouldn't suck properly ?...and maybe I shouldn't enclose a motor in a vaccum like that ???? I don't know.

It doesn't have to look pretty. As long as it works uno.

thanks mate.

If you could get a bit of electricians conduit or similar that was a reasonable fit through the centre of the shaft and bracketed it on the outside end you may get a good enough seal for a vacuum chuck. I have no experience with vacuum chucks either but skew said you didnt want a perfect airtight fit. If the pvc pipe went most of the way through there would be less leakage. I dont know if the pipe could handle the friction of rubbing on the inside of the shaft. Greased up may help solve that problem.
As i said no experience but just a thought.

That idea may do David. Thanks. I don't know. I fear that if I don't do something properly around that shaft, with all that rpm that it just won't last. Thats why I brought up the bearing before.

The shafts 24mm. Was thinking of finding a bearing with inner diameter equal to that and then maybe I can attach the hose to the outer diameter with some kind of wooden adaption between.

Will need to find a pulley to fit that 24mm shaft at least. All the pulleys I'm used to are imperial.

What you might consider is swivel or rotary airline fittings.SMC, Festo, Norgren etc all have fittings to handle this problem. Low cost and very effective. I would not be to concerned with wear as they are designed to handle a active life cycle anyway they are relatively low priced enough to buy 3-4 at a time
http://www.smcetech.com/CC_host/page...MC,CNN_US,3069))

Nitto are one of the best for snap lock type couplings for air lines etc. Not the cheapest but if you want reliability then Nitto is what you should go for.They also have rotary coupling with the snap lock capability. So you would kill two birds with one stone, so to speak. You certainly can buy much cheaper, but they wont last.

http://www.nittokohki.com/en/cupla/d...ent.asp?id=187

Just click on the links to bring up a comprehensive pdf file on each product

I'll watch this thread with interest, Jake. I'm still a little fuzzy on the whole chucking issue, especially the more inventive ones. Like you I look at the idea of a "jam" chuck with some scepticism. The idea of lightly jamming something into a hole and then spinning it towards your head at the speed of light seems somehow less than sensible. The vacuum chuck idea doesn't fill me with confidence either.

Still, I guess it's a matter of "Oh yea of little faith...". The concepts obviously work and are an important part of the woodturners' bag of tricks. I'll therefore watch you & others tackle the issue of jam chucks & vacuum chucks in your usual pragmatic and indomitable manner.

Wayne

I took a hunk of close grained hardwood,(in my case walnut) and turned a 3" x 2-1/2" long cylinder. Then I turned a 1/2" long nipple that fit snuggly into the hole in my spindle. Now I had a square shoulder that I could put an o-ring into. This o-ring butts up against the shaft itself, and I did it using a 1/16th parting tool deep enough to hold the o-ring with the compression of the rubber of the o-ring only. Next I reversed the piece and turned a recess to fit a sealed bearing that I bought at a big box store. A 1/4" npt fits into the bearing with very little modification. I used some epozy to glue the bearing in place being careful to make sure I didn't lock the bearing with excess glue. Once the vacuum is hooked up, the o-ring seals nicely to the spindle. I usually pull around 22hg mercury with mine. I got pics somewhere. If anyone wants to see let me know and I'll try to dig them up. Hope this helps. Paul
BTW you MUST seal the wood with multiple coats before using this adaptor

Merry Christmas Jake,
I have a ton of info (well, about 6+ meg of data files and pics) on vacuum chucking systems. I am happy to share it all with anyone who is interested, so just send me your email address (Contact can be made through PM or Email by clicking on User Name). I will post one here on the "Dual Bearing Rotary Vacuum Adapter by Al Crandall". I bought this unit from Al in disassembled form, but here are his "do it yourself" instructions.

It's not a good idea to enclose a motor in a vacuum. They overheat due to lack of air-flow. That's also why you need some sort of relief valve in the vacuum line if you're using a shop vac; so some air still passes through the motor to cool it.

I should've mentioned that if you use the airline method (And Hughie is right: Nitto fittings are what's used to clip air-guns & other pneumatic tools to the air lines ) you really need to use a high-flow vacuum pump because of the narrow lines - they'd choke a vacuum cleaner.

If you use something like my tin can method (which is just a variation of what you suggested by enclosing the lot, really) then you're better off using a shop vac. You can also drill a hole in the side of the tin can and use a hose clamp around the can to partially cover the hole, to regulate the vacuum and get that little bit of air flow through the motor. (You might've realised by now that a vacuum cleaner doesn't make for the strongest gripping vac chuck, but it's certainly the cheapest and is good enough for light touch up work. )

Perhaps a simple sealed bearing on the end of the shaft would be enough to seal that end of the headstock, to make the tin can idea work? I've included a pic of what I mean, just to explain it a bit better...

Thanks everyone for your help. Diagrams sold me Skew ! ..ta. Have to get a bearing.

Apricot try this it's cheap & easy
Turn a piece of chipboard on a faceplate, bore a central hole & countersink, get some copper pipe, flare & araldite in the hole. I had to grind the pipe down to fit through the headstock. Find a small bearing, mine was an old pool pump bearing, araldite a piece of pipe into the bearnig, find some plastic tube to fit the bearing pipe & the copper pipe, doesn't have to be perfect fit. Fit faceplate to the lathe feeding the copper pipe through the headstock, slide pastic tube to the copper pipe, seal both ends using duct tape and bob's your uncle. You may need to pack out the bearing to fit into the vacumn cleaner hose but just use any sort of tape, masking works well. The only thing left is to suspend the vacumn cleaner hose so that it doesn't drag down on the assembly. Having trouble adding photos so PM me your email address and I'll send photos. You cannot pull the piece off no matter how hard you try but you can slide it off sideways.I forgoy to say contact cement rubber to the face of the chipboard, I used an old wetsuit I no longer fit into.
Allan

Thanks Allan for your help. I get ya. Have to find some parts I think.

AT don't worry about that let me know your addres & I'll post the bearing tube & pipe(fold up chair leg), all you need is the copper pipe, rubber & chipboard
Allan

Thanks Allan. I'll message you.