Vacuum Chuck

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

bertterbo

Established Member
Joined
18 Apr 2022
Messages
79
Reaction score
18
Location
North Wales
I'm thinking of purchasing a vacuum chuck setup. I currently don't have a compressor and have no real need for one, so instead of going the Venturi route, I plan on just getting a vacuum pump as they're much smaller and less noisy. I also have plans to do some wood stabilisation at some point, so that would be another use for a vacuum pump.

My planned parts are :


And then for the pump, which from my research, needs to be at least 3 CFM, I thought I would go with :


Is this all going to be compatible? will I need anything else? I'm not sure what connections may also be needed?
 

flh801978

Established Member
Joined
21 Dec 2008
Messages
1,449
Reaction score
104
Location
Sheffield uk
I have a vacuum setup on my graduate lathe which has a bearing on the outboard end with a large dia 15mm pipe to the pump
i have a bigger pump than that one you linked to when i use it ....but i have one of those too and i have used it to see if it works ( slower to come down to full vacuum)
your lathe has a hollow spindle?
The force on only a 100mm chuck is amazing you cant pull it off
i have 50,100,150 and 200mm chucks
 

bertterbo

Established Member
Joined
18 Apr 2022
Messages
79
Reaction score
18
Location
North Wales
I have a vacuum setup on my graduate lathe which has a bearing on the outboard end with a large dia 15mm pipe to the pump
i have a bigger pump than that one you linked to when i use it ....but i have one of those too and i have used it to see if it works ( slower to come down to full vacuum)
your lathe has a hollow spindle?
The force on only a 100mm chuck is amazing you cant pull it off
i have 50,100,150 and 200mm chucks

Yep, it has a hollow spindle. It's the Axminster 406 if it helps.
 

Paul Hannaby

Established Member
Joined
1 Sep 2011
Messages
926
Reaction score
96
Location
Gloucestershire UK
I'm not sure if the pump spec is correct but it states the maximum vacuum is 5Pa. You would need a vacuum of at least 10"Hg which according to the internet is 33863Pa. That's a big difference to 5Pa...

Once you have all the equipment, you will also need a bleed valve to be able to control the vacuum and a vacuum gauge to tell you what vacuum you are pulling. You would also need the pipe work and probably a connector for the pump to be able to connect everything together.

One thing to watch out with the holdfast chucks is not to use too high a vacuum. If you do, the rubber seals compress to the point where the plastic body of the chuck creates indentations in your workpiece.

This might be of some use - Make your own vacuum chuck | Paul Hannaby Woodturning
 

bertterbo

Established Member
Joined
18 Apr 2022
Messages
79
Reaction score
18
Location
North Wales
I'm not sure if the pump spec is correct but it states the maximum vacuum is 5Pa. You would need a vacuum of at least 10"Hg which according to the internet is 33863Pa. That's a big difference to 5Pa...

Looks like it's measured in thousands, as other sites list it as "5Pa/0.05Mbar"

0.05Mbar == 5000 pascals

0.05Mbar == 1.47 inches of Mercury

So still pretty far off 10.

Are you sure it needs to be at least 10? Even the £300 vacuum pumps still say around the 5Pa mark? some even less.
 

Paul Hannaby

Established Member
Joined
1 Sep 2011
Messages
926
Reaction score
96
Location
Gloucestershire UK
A total vacuum (at sea level) is 29.7"Hg. Most decent vacuum pumps will reach around 25"Hg. For a 6" chuck I adjust the bleed valve to give around 15"Hg. Using the graph in my article, 1.5"Hg would equate to only around 5lb holding force which is nowhere near enough.
 

graduate_owner

Established Member
Joined
5 Aug 2012
Messages
2,110
Reaction score
18
Location
Llandeilo
To flh801978.

Hi, I am thinking of making up a vacuum chuck for my graduate. Can you post (or email me) pictures and details of yours please, especially details and dimensions of the 'swivelling' bit? Many thanks, in anticipation.

K
 

Yorkieguy

Established Member
Joined
1 Jun 2012
Messages
161
Reaction score
576
Location
Cottingham, East Yorkshire
Bob Chapman, who is a member of this forum (and West Riding Woodturners Group which meets at Bingley), was for many years a well-known and highly-regarded professional demonstrator on the 'club circuit' until he retired. Bob made his own vacuum chuck some years ago and provided details of how he went about it.

You might find these articles of help and interest:

www.bobchapman.co.uk/-1-_Making_a_vacuum_chuck.pdf

www.bobchapman.co.uk/-4-_Vac_chuck_modifications.pdf

About Bob:

www.bobchapman.co.uk/index.html

Bob's contact details on this forum:

Bob Chapman

Hope that might help.

Every success with your vacuum chuck project.

David.
 

Bob Chapman

Established Member
Joined
23 Apr 2007
Messages
195
Reaction score
86
Location
West Yorkshire
Well, thank you David (Yorkieguy) for your compliments. Having seen Paul Hannaby's excellent contribution I didn't think mine could add much to what he'd already said, but it is nice to be remembered!
One thing I might add is that vacuum power is not well understood and, as both Paul and I point out, it is proportional to the area of the chuck. I once sold a perfectly good vacuum pump to a chap who contacted me a day or two later saying it was useless because it 'didn't suck'. Of course I gave him a refund and took the pump back. It still worked perfectly.
I suspect (but can't know for certain) that he'd switched it on and put his finger over the inlet pipe, experienced almost nothing and decided the pump didn't work. What he hadn't taken into account was the area of the inlet - a pipe perhaps 1/8 inch diameter or so. The vacuum pressure on such a small area would be tiny, just as he'd experienced. Connect it to a chuck with a diameter of, say, four inches and the power is enormous.
I only mention this because that initial 'put your finger over the inlet' is an obvious and compulsive thing to do, but beware your expectations - don't think you're going to feel much!

Bob
 

flh801978

Established Member
Joined
21 Dec 2008
Messages
1,449
Reaction score
104
Location
Sheffield uk
I have one of the little ones as well as a larger gast pump here’s the label and that will easily pull down to 15 inches
My gast pulls to 24
 

Attachments

  • 340EF859-7F07-4288-A72D-91CE29AC3912.jpeg
    340EF859-7F07-4288-A72D-91CE29AC3912.jpeg
    135.8 KB · Views: 0

flh801978

Established Member
Joined
21 Dec 2008
Messages
1,449
Reaction score
104
Location
Sheffield uk
This for GO is my connection for the outboard of a graduate
 

Attachments

  • 98E9ABE2-0B4F-4B7E-86EB-8DDE36F4A96D.jpeg
    98E9ABE2-0B4F-4B7E-86EB-8DDE36F4A96D.jpeg
    173.1 KB · Views: 0

flh801978

Established Member
Joined
21 Dec 2008
Messages
1,449
Reaction score
104
Location
Sheffield uk
So you have a LH threaded boss then a pair of 2RS sealed bearings a spigot glued into the bearings with loctite then a triple outlet connector with inlet pipe gauge and relief valve.
Ian
 

Bob Chapman

Established Member
Joined
23 Apr 2007
Messages
195
Reaction score
86
Location
West Yorkshire
A high CFM number doesn't give you a better vacuum, it just does it quicker. A 3CFM pump will be fine. It shifts 3 cubic feet of air per minute. The total volume of your vac chuck system is a small fraction of a cubic foot. You'll achieve the necessary vacuum within seconds.
 

Paul Hannaby

Established Member
Joined
1 Sep 2011
Messages
926
Reaction score
96
Location
Gloucestershire UK
Where higher cfm comes in to play is where the wood (which is often porous) is leaking air and reducing the vacuum. A higher cfm pump will maintain the vacuum better than one with a lower rating. Even with an 8 cfm pump, I still find occasionally I find pieces of wood which won't hold on the chuck due to the porosity of the wood. Sometimes that can be got around by covering the wood with clingfilm but that only works if you aren't trying to work on the area where the clingfilm is!
 

Tris

What am I doing here?
Joined
28 Nov 2018
Messages
617
Reaction score
427
Location
Moreton in marsh
I'm just at the thinking stage of building a vacuum chuck set up having been given a pump and 6" diameter x 2½ft long piece of solid pvc to turn the chuck from.

My question is: how much effect does the depth of the chuck 'cup' have? I built a Longworth style chuck some years ago and had to use a spacer block on the faceplate to prevent it fouling the motor. The Jet 1442 has the motor in a most awkward place, so I wondered whether to make a deeper cup to allow clearance.
 

flh801978

Established Member
Joined
21 Dec 2008
Messages
1,449
Reaction score
104
Location
Sheffield uk
These are my vac chucks
You can see the depth and the length of the fitting…biggest 200mm small 45mm
 

Attachments

  • 0007C205-924F-40D7-89C1-EB2399FC808B.jpeg
    0007C205-924F-40D7-89C1-EB2399FC808B.jpeg
    161.2 KB · Views: 0
  • 9023DB2B-5016-4C90-84B0-A2216884AE7E.jpeg
    9023DB2B-5016-4C90-84B0-A2216884AE7E.jpeg
    154.3 KB · Views: 0

Tris

What am I doing here?
Joined
28 Nov 2018
Messages
617
Reaction score
427
Location
Moreton in marsh
Thanks for posting those pics, looks like I can get enough depth to clear the motor with no problem then
 

Lazurus

Established Member
Joined
22 Sep 2017
Messages
1,108
Reaction score
225
Location
Norfolk Broads
I made my own set up to suit my VB36
 

Latest posts

Top