Vacuum Chuck Adapter

[Russell Neyman]

What's the best vacuum chuck adapter for a Jet 14-42? I'm about to purchase the Precision Machine version (woodturnerscatalog.com) but the size options only list the Jet 12-36.

[Bob Bouis]

Ask ahead of time to make sure it'll work.

But I'd just make one. It's round! And pretty straightforward turning. All you need is a bearing and a nipple.

[Jeffrey J Smith]

they are pretty easy to make, but if you're going to buy one, check out JT Turning Tools. They work great - never a leak.

[Russell Neyman]

JT wants $160 for the 14-42 version that threads onto the end of the shaft. By "easy to make" I'm assuming you mean the type with o-rings that slips into the handwheel. I'm not sure what to use for the bearing housing.

I'm surprised there aren't more Jet lathe owners who use vacuum chucks. I expected more responses.

[Steve Nix]

I use the threaded rod system the hold fast sells on my 1642 Jet. Works great for the past 4 years

[John K Jordan]

JT wants $160 for the 14-42 version that threads onto the end of the shaft. By "easy to make" I'm assuming you mean the type with o-rings that slips into the handwheel. I'm not sure what to use for the bearing housing.
I'm surprised there aren't more Jet lathe owners who use vacuum chucks. I expected more responses.

I don't know about the 1442 but the 1642 apparently had a problem with the handwheel design such that the type of adapter with o-ring seals didn't work. JT Turning tools offered a replacement hand wheel with a vacuum adapter for the 1642 but it was expensive. Lots of people went with the hollow threaded rod type. I planned to machine a new hand wheel for my 1642 but then got a PM5320b and two different Oneway vacuum adapters. The first one required removing the hand wheel each time I wanted to use a vacuum chuck - a significant inconvenience. The second is a rotary adapter with the o-ring seals which simply slips into the hand wheel - much better!

I bought the bearings and parts to build a rotary adapter from scratch. I plan to machine a housing for the from aluminum but construction can be simpler than that. I can imagine turning a piece from lignum vitae that would hold the o-rings and adapt to the bearing. Also, Joe Woodworker has instructions and parts for a design that could be adapted to fit many lathes, perhaps the 1442 (depending on the hand wheel design): https://www.joewoodworker.com/veneering/vacuumchucking.htm

If you haven't see Joe's web site he has a lot of good info on building vacuum chucks, etc as well as a more complex vacuum system suitable for vacuum bagging and clamping as well as vacuum chucking on the lathe. He sells everything you might need at extremely good prices, including an excellent vacuum chuck gasket material.

JKJ

[Russell Neyman]

John, et al. Very helpful. Thanks.

[Robert Willing]

You may want to check this one out just ran across this while looking for tools https://www.harrisonspecialties.com/vacuum-chucks-accessories/

[Edward Weingarden]

I use the Oneway Rotary Adapter on my Jet 1642 (currently sells for about $85). I don't know if it can be used on the 1442. Removing the hand wheel and placing the rotary adapter takes me less than a minute (two set screws) so it's not an issue for me.

[Russell Neyman]

After pondering all of this and watching a few videos, I made myself a very nice chuck that doesn't require an adaptor using a threaded lamp tube and ball bearing. Works very nicely!

Thanks, all.

[Guy Mueller]

search on internet and You Tube they are easy to make

[Brice Rogers]

I saw that John and Russell have successfully made their own. I machined one out of 6061 aluminum on Saturday. I put in two 6200-2RS (sealed) bearings. I epoxied the bearings into the housing and the shaft into the bearings. Then I tried drawing a vacuum. It leaked so badly that I could only draw 5" Hg. I applied wheel bearing grease to the bearing and it sucked it right in. LOTS. And the vacuum would momentarily go up to 20" but long term was probably going to drop down. I did a post-mortem on one of the bearings and found that the rubber seal was about 0.014" larger in diameter than the inner race OD. So, roughly a 0.007 gap all the way around.

I bought the bearings from VXB in Ca. off of fleabay. I contacted the seller and was told "our bearings are non contact rubber sealed bearings, so there will be that gap there. I am not familiar with a company that sells contact seals." Although I did not ask for it, they volunteered to refund my $. Very nice.

I contacted the frugalvacuumchuck fellow and he told me that he has a bucket of unusable chinese bearings that also suffer leakage but mentioned that he switched to a US manufacturer. I would buy bearings from him, but right now I'm all set up for 6200-2RS bearings and his are a slightly different size (imperial rather than metric).

Someone suggested buying Japanese or US mfg bearings. But some of the US mfrs (like Timken) have gone off shore and some of the Japanese make bearings in India.

John or Russell could you share the mfr's name of the bearings that worked for you? Also, if anyone else has a purchased unit, could you check the mfr's name - - it should be written on the side of the bearing. TIA.

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[John K Jordan]

This is what I bought, not cheap but has good seals: https://www.veneersupplies.com/products/Ball-Bearing-for-Vacuum-Chuck.html

Did you see his whole article?
https://www.joewoodworker.com/veneering/vacuumchucking.htm

JKJ

[Brice Rogers]

Thanks John,

Yes, I did read the whole article. Thanks.

When I was looking at his site earlier, I missed seeing the bearing link. If I cannot find a suitable 30mm bearing, may end up buying the bearings from him. My adapter is large enough in diameter that if I had to, I could bore it out from 30mm to 1-3/8" and still have a 0.100" wall thickness. I would probably still use a pair of bearings rather than a single one.

I think that I also need to buy a higher volume pump. I did a science experiment this afternoon and measured it's CFM. My current pump is a little low on volume and that is exacerbating the leakage problem.

Thanks again.

[Jerry Chandler]

I agree with the JT Turning Tools system. I bought one several years ago for my Jet Mini. I had to buy their replacement hand wheel so the adapter would fit inside but it was reasonable and worked. When I got my 3520B I was surprised to find the JT adapter fit the hole in the hand wheel perfectly, so now I can use my vacuum system on either lathe. Vacuum sure makes a lot of jobs easier. Also, thanks guys for the links to materials. That really helps us tinkerers!

[John K Jordan]

I think that I also need to buy a higher volume pump. I did a science experiment this afternoon and measured it's CFM. My current pump is a little low on volume and that is exacerbating the leakage problem.


I've never measured the CFM on mine but I can see how that would help with a leaky system. It's bad enough with porous wood and imperfect seals to the wood!

Too bad we don't live closer or I could loan my vacuum pumps for comparison. I bought a new one from Joe Woodworker and a used one from a woodturner.

JKJ

[Alex Zeller]

Brice, Since you machined that piece of aluminum why not add the ability to install a lip seal?

[Brice Rogers]

I learned something surprising that I will share.

There are two types of "sealed" bearings. One is called the "non-contact" seal and the other is a contact seal. I'm guessing that the non-contact seal is more common. I was told this by my bearing supplier (VXB) that they supply non-contact seals. What this means is there is an air gap between the rubber and the inner race. In my case there was a roughly 0.007 " gap. I shake my head in disbelief! :eek: I don't understand why they don't just call it a shielded bearing. But perhaps in a shielded bearing, the gap is even wider. Perhaps the standard non-contact "sealed" bearing has a smaller gap.

When I do a google search, I find some mfrs that offer a contact type of sealed bearing and some the non-contact type. But when I look at sites like ebay, Amazon or McMaster-carr, I don't see that they provide the detail to figure which you are buying.

Alex, you mentioned a lip seal. Is that a seal that I could buy and attach or is this a seal that I would need to machine myself? I'm familiar with automotive lip seals on wheel bearings, but am unaware of their use on smaller shafts (mine is about 10 mm). Could you provide more info?

[Alex Zeller]

It's a seal you can buy. Sealed bearings are designed to keep things like water out of them, not to hold a vacuum. Since you aren't looking for perfect I'm sure an oil seal would work. They are cheap and easy to get. They come in the same size as the bearings, just thinner, and will press into the aluminum housing and the 'lip' will seal against the shaft. You'll have to modify your design some. You'll want the spring inside the seal to be on the non-vacuum side and if at all possible you will want the seal between the vacuum and the bearing. Grease doesn't like being pumped down in a vacuum (they do make special grease that does). If you put the bearings under vacuum you will most likely pull some of the grease out of the bearing and onto your work. I'm assuming that if you machined the aluminum housing then it shouldn't be too much harder for you to make room for a seal.
387670

[Brice Rogers]

Thanks for posting, Alex. You have helped to expand my knowledge base.

If I could find the right diameter seal, I could place it on the shaft connecting the two "sealed" bearings. I've also thought if just machining a tight tolerance steel or aluminum seal with minimal clearance (like 0.001) and place it between the two sealed bearings.

There are a lot of do-it-yourself designs on the internet that don't rely on a seal. Perhaps those folks stumbled onto a contact-type sealed bearing. I ran across on mfr. that mentioned a bearing that was triple sealed (I suspect that it is the contact type). I'm wondering what companies like Harrison Specialties, and frugalvacuumchuck do? I wonder if they add a seal in addition to the double shielded (contact-style) bearing ? When I read the description from JT Turning, it could be interpreted that there is some sort of proprietary seal in there. hmmm.... food for thought.

Thanks again for pointing me in the direction of shaft seals.

[Larry Copas]

A couple pics of my vacuum adapter I made a few years ago. I use it a lot and haven't had any problems. Can't remember what bearings I used or where I got the seal from but you can get the general idea from the pics.

387695

387696

[John K Jordan]

A couple pics of my vacuum adapter I made a few years ago.

Very nice work Larry!

JKJ

[Brice Rogers]

Thanks for posting, Larry. Looks very nice.

[Brice Rogers]

Larry, I have a supply of the 6200-2RS (non-contact) bearings (that leak - - as I reported previously). They are 30mm OD and 10 mm ID. I found a source for a grease and oil seal. I'm wondering if you could look at the specs below and comment as to whether this seal is likely to work or whether I'm looking at the wrong type of seal:

Oil and Grease Seal Double Lip Shaft Dia. 10mm Width 7mm For Bore Dia. 30mm Nitrile Rubber Lip Material.
Brand : VXB
Item Sku : TC10x30x7
Type : Oil and Grease Seal TC 10x30x7 mm
Inner : 10mm
Outer : 30mm
Width : 7mm
Size : 10mm x 30mm x 7mm
Oil and Grease Seal Material : Nitrile Butadiene Rubber
Temperature Range : -40° to 248°F

387719

[Larry Copas]

Looks similar to the one I used but smaller. My seal measured 18 x 40 X 9. I really can't comment on if it will work as I'm one of those shade tree machinists and not that knowledgeable.