home made rotary adapter

Re: home made rotary adapter

John Lucas

>John

You need to diagnose the source of the problem. Start with the bearing. Put your finger over the bearing and if you have full vacuum then that rules out the distance from bearing to your vacuum motor. put the bearing back in place and put your finger over the spindle nose. If you don't have full vacuum then abviously the problem is somewhere inbetween the bearing and the nose of the spindle. Most of the time it's where the bearing goes into the spindle adaptor. I used closed cell foam sheet I buy at the hobby store to make a gasket.

If this is good put your vacuum chuck in place and put your finger over the hole. Many of the leaks are here and can often be stopped by the use of some closed cell foam place between the spindle nose and the bottom of the threaded faceplate.

If that's good then put a smooth solid hardboard over the vacuum chuck. This is another good place to loose vacuum. If you made the chuck from wood you could be losing vacuum through the wood. Seal it with lacquer of even plastic tape.

You should be able to find where the leak is using this system

Re: home made rotary adapter

Don Evans

>John:

Are you sure they are "sealed" as opposed to "shielded". If the sides of the bearing are covered with a metalic type material, they are shielded and will leak. If covered with a black soft (finger nail will make an impression) material then they are sealed. You should have double sealed, meaning this material on both sides.

Any of this help?

Can you provide the name brand and number of the bearings you are using?

Don

Re: home made rotary adapter

Andrew Hilton

>I've had this exact thing happen a few times when making these. I don't know if I mentioned it on my webpage or not how I've fixed them.

Turn your vacuum on and have everything hooked up so that you can pull some vacuum. Oh, first of all, you did get double sealed bearings, right? Probably have a black rubber/plastic covering the balls? Those are what I use to make mine. Anyway, there's a leak at that black rubber/plastic covering sometimes. I just push a couple of places around on that while the vacuum is on and it'll suddenly start pulling a full vacuum.

You might have to do this a few times before it finally seats and you won't have to do it anymore.

Re: home made rotary adapter

Don Evans

>One other thing I thought of also in addition to all John said is that not all spindles are sealed. Your spindle could have a hole or holes in it made during the manufacturing process. You may have to install a hollow tube between the bearings.

Don

Re: home made rotary adapter

John F

>From your discription my bearing would be double sealed.

The leak is coming thru the seals on the bearing, between the center race and the sealing rings.

Re: home made rotary adapter

John F

>Yup, thats exactly where its leaking, I'm looking for my can of wheele bearing grease, thought I would try applying some to that area to see what it does.

thanks for the suggestions, on my way out the door to give it a try.

thanks,

John F

Re: home made rotary adapter

John F

>thank you for all the suggestions.

the leak is thru the sealing rings on the bearing.

Re: home made rotary adapter

John F

>Thank you to all who responded. I believe its taken care of now.

I played with the seal and got it up to 9 inches, per a suggestion by Andrew Hilton.

A generous application of ca glue around the perimiter of the outer race has gotten it up to 15 inches. Next step is to coat the wooden block with lacquer.

After that I will be looking for something to use for a seal, my only unused mouse pad isnt large enough to cover the 9 7/8" disc on my faceplate.....guess I will have to cruise around the merchantile store and see what I come up with.

again thanks to all who responded,

I would also like to thank Al Crandall for his doc on shop made vacuum chuck, also William Noble for his document...

and to everyone on this forum from whom I have learned so very much

John F

Re: home made rotary adapter *LINK*

Phil Joines Krum, Texas

>I use a PSA backed PVC Foam Sheet from NSC. The 1/8 is $7.10/ foot x 54" wide.


MSC gray foam

Re: home made rotary adapter

� Joe Millsap

>go to UPS and they will sell you a small piece of packing material to make gaskets out of. Yoou can use a cigarett to let the smoke show where the vacuum leak is. Where it is leaking it will suck the smoke in

Re: home made rotary adapter

Leo Van Der Loo

>Hi John, I had a leaking bearing also, actally 2, here's what I did, I don't know what size bearings you used, but I had a plastic uhmw kind of washer, like the ones used on toilet seats(OK I can hear you snicker there) slit that on the hose barb and against the bearing, that worked for me.

Never tried Andrews idee(thanks Andrew) if that works, that would be the best fix.

Have fun and take care

Leo V

Re: home made rotary adapter

Dave Peebles

>Hi John,

I have been using something call "Foamies" that I get at the local Wal-mart. It is in the craft section. They come in 9" x 12" sheets about 2mm thick. I use the 3M spray adhesive to attach it to my chucks. It seems to be very similar to the material that Oneway uses. The best part is that it cost .33 cents a sheet. I think they also have some that is selt adhesive.

Works great on my vacuum chucks!!

Best wishes,

Dave

Re: gasket material

Al Crandall

>I like the "Funky Foam" sold at Hobby Lobby. It comes in a metric size which approximates 11X15 inches, and is less than $1. Try Michael's or any of the hobby and craft supply stores near you. The funky foam comes in VERY bright neon colors and in 2mm thickness with and without adhesive backing, and in 3mm thickness without adhesive backing. Just spray on an adhesive from a pressure can from Lowe's or Home Depot. I have recently had a problem with a friends rotary adapter. He almost used my design but not quite. I replaced the bearing for him with the one from Lowe's and it still leaked just where you said your's did. I was hoping that Andrew's solution was the cure for this. None of the three I use in my shop have more than about 1/2" Hg leakage in the total system. There are apparently a lot of my adapters out there, and I am getting worried about this leakage problem. Maybe a different supplier needs to be recommended. I wish I had an answer.

Re: gasket material *LINK*

Leo Van Der Loo

>I've used some off the thin foam also, but like the tool drawer foam much more, home depot sells it, gives me a better seal when the bowl/platter is a little off, and not so thick as to let the turning move, it cost more but stands up better, anyway I thought to throw it out there, fwiw

Have fun and take care

Leo V


http://homepage.mac.com/l.vanderloo/PhotoAlbum18.html

Re: home made rotary adapter

Andrew Hilton

>Don't use the grease. It'll get sucked up into your vac pump!

Re: home made rotary adapter

Andrew Hilton

>When you do your wood sealing, be sure that it's completely dry before you pull a vacuum through it. You might (as I've done before) notice that some of the uncured finish will suck right through the wood and into your vac pump. I noticed this when I saw some arterial blockage starting to accumulate in the vac hose.

Re: home made rotary adapter

Andrew Hilton

>That's the stuff I use most of the time. The self adhesive ones from Walmart. It doesn't hold up to severe abuse and does tear a bit sometimes.

I've also used the synthetic chamoise (spelling?) cloths for drying your car. They hold up better but you have to have a better fitting rim on your bowl/form to make a good seal. But it does make a good seal and holds up a long time. The natural ones get stiff and crack.

Re: gasket material

John F

>In my case the bearing came from NAPA auto parts, no Lowe's anywhere near here. think my bearing problems are over. now its just a matter of sealing the wooden block, I used oregon myrtlewood to make it and it seems to allow a lot of air thru. So far two coats of lacquer and I'm up to 22" from 15 after fixing the bearing problems. Maybe I'll just dunk the thing in lacquer next.

thanks again for that document you wrote up, took lots of ideas from it

John F