Vacuum chuck questions

[Mark Detrick]

So I have my new PM 3520B all setup and working great. I now want to come up with a vacuum chuck setup for it. I have been watching Craigs List for a Gast 0523 pump but I have not had any luck picking one up at a reasonable price. I do have a 5HP compressor with a 60 gallon tank that sits in my garage, away from my workshop, and I have air lines piped into the workshop. With that said, I have been looking at the Holdfast Vacuum Generator. I have read other posts on the site that suggest that the Holdfast "system" works quite well for them. Since I have never been one to conform to much of a "system", I'm wondering about using a Holdfast Vacuum Generator and mix-and-match the other pieces. Possibly use a JT's vacuum adapter and maybe make my own chucks.

Does anyone have experience or information as to this type of a setup?
Should I just bite the bullet and get a Gast pump?
Maybe there are better solutions that I'm not aware of?

Your comments and suggestions are greatly appreciated!

[Chip Sutherland]

Mark

There have been a few recent threads on this topic. I acquired a piston pump from a friend in my woodturning club who bought 10 off of E-bay. Then he put together a DIY package and sold them to club members but he basically used the same components from this link

http://www.veneersupplies.com/produc...ng-Add-On.html

with exception of an 2nd sealed bearing and a 2nd valve.

I posted my vacuum pump setup in the following thread built for about $137. Pictures didn't load on the initial post so look a few down. I made my own vacuum chucks, too. I am planning on buying JT Turning Tools vacuum adapter at SWAT this year but it was fun building my own.

http://www.sawmillcreek.org/showthre...ect&highlight=

I didn't post the instructions in my thread but here is the link to the ones I used. The difference being the chuck adapter steps show 1 bearing but I used 2 in a deeper hole. These also have the part list if you choose to build one.

http://www.goldentrianglewoodturners...0Chuck2008.pdf

Like I said there have been several threads with great Q & A within the last 3 weeks on SMC. Not to discount Holdfast but I built my vacuum chuck because my HoldFast stopped working and I really hated to hear my pancake compressor cycling so much (too loud). I spent more on the Holdfast setup than I did building my pump.

[David C. Roseman]

Chip, curious is to why you used two bearings in your DIY adapter. Seems like it would just make things harder to seal and introduce another source of leakage.

David

[Chip Sutherland]

Here's the easy answer.....because the DIY kit I bought had 2 bearings and that's how I folks recommended it. My woodturning club has a bunch of retired engineers and they relish the thought of building their own stuff. The version JT Turning Tools makes uses 2 bearings and I suspect that was the influence.

[David C. Roseman]

Chip - Ahh, o.k., thanks!

David

[Mark Detrick]

Thanks for the info

[Fred Belknap]

I have the holdfast system. It works most of the time, but if there is the least leak or porous wood or seal not real good it won't build enough vacuum. I end up quite a bit of the time using it as a jam chuck using the tailstock. It helps quite often to finish the inside of the bowl and let set overnight. If I had it to do over I would go with a vacuum pump.

[Thom Sturgill]

As far as mix and match go, it does not matter in the slightest. Use whatever vacuum source, connector, and chuck work for you. I have always made my own chucks. I bought the holdfast for my small lathe, but when I upgraded to a larger machine I did not want to use the headstock adapter, but bought one from JT Tools that included a new handle (Jet 1642). I have been happy with it, but built a pump station when the machines were in separate buildings and I got tired of moving the holdfast. Now that everything is in one shop, I could use either, but have dedicated the holdfast to the smaller lathe.

I agree with Fred about sealing porous woods, That helps with any vacuum pump, While a high CFM pump makes it less needed, I worry about getting a working vacuum too fast. I have crushed a bowl or two where there was an unseen crack or too thin bottom. My pump is low cfm, actually lower than the Holdfast though it achieves a higher vacuum.

[John Aspinall]

Chip, curious is to why you used two bearings in your DIY adapter. Seems like it would just make things harder to seal and introduce another source of leakage.

I think the idea is that the bearings are "in series" with respect to the airflow; the unwanted escaping air has to flow through one and then through the other. There's a single path for leakage through the adapter, each bearing adds resistance.