Homemade Vac Chuck 'Chuck' options (Warning- picture heavy)

[SVB]

So, always wanted a vac chuck system but not sure of options / how to sort the chucking? There are many articles / commercially available vac systems available, indeed, some lathes are now being supplied with the facility built in. I have an airpress pump and rotary adaptor that was surplus (don't ask) but could not bring myself to spending the several hundred pounds asked on commercially available chucks. I have made myself a small and large drum chuck and a vacuum faceplate that all work well but all have diverse methods of construction so I thought I'd share them here for info.

(And perhaps as a resource - mods, do we have a "how to do...." Sticky anywhere or do we rely on the search functionality?)

My chucks are all made to fit my Vicmarc lathe. This has a M33 X 3.5 thread and also a 34mm OD X 8 mm locating boss which I think is standard DIN fitting. However, that said all the methods below will work for you, just adapt the thread to suit.

I've added comment to the photos to explain each method.

Overall, I am very happy with the set of chucks I have that deal with almost all work I need. If I didn't have the airpress fitting, the tapped nylon worked really well and at 100mm OD gives really good support to any work. The nuts worked ok but were a pita to drill / tap and really need further turning on the i/d to match the lathe headstock location boss and ideally also on the opposite end o/d to provide additional location for the MDF disc if I were remaking this.

Hope this helps / interesting,

Simon

 

[Robbo3]

Nice one Simon.
Just about to resurrect my vacuum chuck project, started last year.
Where did you source your foam & nylon. Everything I've looked at seems very expensive.

 

[SVB]

Hi Robbo,

Thanks for kind words.

Foam was just self adhesive 2mm stuff from hobby craft. Nylon I had in workshop - saw at car boot for £10 for a piece 100mm OD X 500mm long so too good to leave there even if I did not know what I was going to do with it at the time!

S

 

[Robbo3]

I've set up a small vacuum chamber using a stainless steel saucepan (charity shop) with a lid made from clear 8mm polycarbonate which was drilled & tapped 1/4" BSPT to take an 8mm push fitting for nylon airline. Polycarb, tap pneumatic fittings & airline all from ebay.

Got a cheap 1.8CFM Rotory Vane vacuum pump off ebay (chinese seller but dispatched from UK). I see a similar 4CFM is currently £77.
The pump is fairly quiet - put-putts like an outboard motor. It pulls a full vacuum, taking the gauge round to -30 & holding it there with an increase in pitch but not much increase in volume. The drawbacks (as I see it) with a smaller CFM pump, is that it takes longer to reach a full vacuum & should the system leak, it may not have enough capacity to compensate.

On my APTC 1628VS lathe I'm not sure the headstock is airtight all the way through because of the long indexing ring which is an interference fit & held on with grub screws - I've yet to test it to find out. I also have doubts about whether anything (nut, faceplate etc) screwed to the headstock will allow a vaccum to be maintained without additional help of some form of seal - a soft washer for the threaded item to butt up against perhaps?

I made two vacuum chucks from 3" & 4" ventilation fittings, the sort used for extractor fans. These are not as heavy duty as soil pipe/fittings. They were hot melt glued into a groove on a wooden backplate that was drilled & tapped to fit the lathe (M33).

If the headstock will hold a vacuum, then it only needs a bearing to be sealed to the outboard end. I envisage using a short length of airline sealed with hot melt glue to the bearing with a double ended push fit connector which can all stay permanently in place allowing quick connection to the vacuum pump as needed.

If the headstock doesn't hold a vacuum, then I have a length of 10mm threaded metal pipe to conjure something up.