New Vacuum Chucks

Stuart Ablett

Member
Messages
15,917
Location
Tokyo Japan
Well, that vacuum rig should be good to go, I got the "Sealed" bearing today, so I set about making up some new vacuum chucks.

vacuum_chuck_1.JPG vacuum_chuck_2.JPG
OK, here are the pieces, I have four sizes of PVC pipe connectors for the bodies of the chucks, four threaded blocks and four chunks of of MDF for the backer boards of the chucks.

EDIT: I would NOT use MDF for the backer boards again, they leak BADLY and needed a LOT of CA glue to seal them. Use some good quality high grade plywood instead.


I pre-drill the threaded blocks, and countersink the holes.

vacuum_chuck_6.JPG
I draw lines from each corner, on the MDF, and then line up the threaded block, and drill one hole, and drive one screw...

vacuum_chuck_3.JPG
...and then drill the other three holes.

vacuum_chuck_4.JPG
Once the dust is cleaned off, I spread the glue evenly on the two surfaces....

vacuum_chuck_5.JPG
...and then drive the four screws to hold the block in place on the MDF backer board.

vacuum_chuck_7.JPG
Now I have four backer boards ready to go on the lathe, once the glue dries.

vacuum_chuck_8.JPG
I had two round boards from when I made the mini cyclone for the shopvac, so I used them, but the other two boards are square, so they had to be rounded off. Turning the MDF is MESSY, I use the DC and I wear the Triton Power Air Cleaner Helmet, and it is still NOT much fun :rolleyes:

vacuum_chuck_9.JPG
Once the piece is rounded, I then use the dividers to mark the outer size of the vacuum chuck body.....

vacuum_chuck_10.JPG
and using the parting tool, I cut a groove in the backer board, to fit the vacuum chuck body. A good fit is needed, it should be snug, but not tight.....

Cont..........
 
Last edited:
.....

OK, some more on these.

vacuum_chuck_11.JPG
OK just a little point here, on the pipe couplings that I'm using, one end has a bunch of numbers and stuff on it, the other end is smooth, so I made sure that I put the smooth end into the groove in the backer board.

vacuum_chuck_12.JPG vacuum_chuck_13.JPG
I drill the center holes in the backer boards before I attach the vacuum chuck bodies, I make sure I use a bit that is SMALLER than the hole in the spindle of the lathe, so I do not have to worry about the bit hitting the spindle.

vacuum_chuck_14.JPG
I used the large cone on my Oneway live center to line up the vacuum chuck body on the backer plate. I used 5 minute epoxy to attach the vacuum bodies to the backer plates......

vacuum_chuck_15.JPG
....and then used silicone sealer to make darn sure there are no leaks.

vacuum_chuck_16.JPG
There they are, ready for some tuning up.

vacuum_chuck_17.JPG
I true up the edge of the vacuum chuck, and round over the edge.

vacuum_chuck_18.JPG
I also put a hole in the threaded block, just in case the chuck gets a bit stuck on the spindle, this will make the chuck easier to get off, make sure you don't drill too deep.... :rolleyes:

Now that these are done, I'll spray on 3 or 4 coats of poly on the MDF, to seal it, as it is very porous.

I'm not sure if I'll attach a seal to the edges of the vacuum chucks, or use a pad that will have a hole in it and NOT be attached to the chuck itself :dunno:

Cheers!
 
Well, now that really looks cool. Not being a spinney kinda guy, I'm curious as to exactly what you'll be turning using this new contraption. Can't wait to see what comes from this!
 
Well, now that really looks cool. Not being a spinney kinda guy, I'm curious as to exactly what you'll be turning using this new contraption. Can't wait to see what comes from this!

Rennie, I will use these to finish off the bottoms of bowls, the bowl will have a tenon, that was held by the chuck while turning, the last thing on the lathe, that most will do is turn the tenon off the bottom of the bowl, or if the tenon is to become the foot of the bowl then you will want to clean up the marks left by the chuck, as well as sand it and finish it.

There are lots of ways to do this, Donut chucks, or just a simple "Jam Chuck" as well...........

This is a "Donut Chuck" and you can see how the bottom is turned off and sanded......

little_cherry_centering_in_chuck1.jpg
Centered

little_cherry_bottom_turned_in_chuck2.jpg
Turned

little_cherry_bottom_sanded_in_chuck3.jpg
Sanded & finished

Here is an even simpler way to do it.....

jamb_chuck_padding_installed4.jpg
Cover the chuck with a pad...

jamb_chuck_centered5.jpg
Bring up the tailstock, and then finish turn the bottom etc.

The thing is, with the Vacuum chuck, it is like magic, you just pop it in place, and then the vacuum holds it, and you turn, sand and finish.

The vacuum chuck is just soooooooo much easier :D
 
OK, I got the new bearing, installed it on the Tekna Tool adapter, and it does not leak at all! :D :thumb: :headbang:

I also had to coat the MDF several more times with poly to get them to stop leaking, Carol, you were right, the stuff leaks like a screen door on a submarine! :eek:

I'll try to choose something else next time around for sure!

Cheers!
 
stu, we're working on the same stuff right now. i'm waiting for a filter for the vac system but in the meantime i started sniffing around a vacuum chuck. i've used the beall tap in the past for wooden chucks so i know the procedure for tapping the hole. this time i decided to use an 8/4 piece of birch that is surplus and should provide enough for several different sized vacuum chucks. so i'm attempting to eliminate the piece you're using the mdf for and just have one tapped piece with pvc pipe glued to it.

but i'm finding even when i carefully line up the tap using a live center, the threads in a wooden chuck fit pretty loosely on my nova spindle. when the chuck finally seats things tighten up. but it seems to me there should be some seating feature at the inboard end of the wooden chuck that bears against the nova spindle...actually there's a bearing race that this 'feature' could seat on. there's a relief machined where the spindle threads terminate that might even provide a spot for an oring to seal the joint between the wooden chuck and the spindle.

your spindle should look the same. what do you think?
 
Thanks for posting the pics and the write-up, Stu. I've had the necessary materials and tools for a while, but just haven't gotten around to making any vacuum chucks. So far, I've gotten along with the Hold Fast chuck I bought around the time I got the lathe, but I want to add a few other shapes and sizes.
 
Ed, I have a very easy answer to your problem, as I had the same problem, the threads are going to leak, for sure.

I make my blocks just a bit thicker than the length of the spindle, then when the backer board is attached to the threaded block, there is only a small space between the backer board and the front face of the spindle.

I cut a rubber washer, or gasket to fit in there, here is how......

I use some rubber sheet that is stiff, but not "hard", if that makes sense.

In >> THIS << thread, Dick Strauss suggests taking a cheap holesaw, of the right size, and sharpening it into a hole punch for sanding discs. Great idea, that I stored away, and pulled out to make the gaskets, or washers I needed for this.

I had a cheap holesaw set that a buddy gave me, after he used it once, to cut a round hole in his motorcycle fairing to put some crash bungs on his bike. I found that one of the holesaws was exactly 1 1/8", the size I needed, but, I would have to grind the inside of the holesaw, so this is what I did.

hole_punch_1.JPG
I put the holesaw together on it's mandrel,
and then mounted it in the drill chuck on the lathe.
I had ground off the teeth of the holesaw on the bench grinder before hand.

hole_punch_2.JPG
I put a grinding stone in the hand drill and then I turned the lathe on, around 800 rpm,
and then I started to grind. I had to dress the stone several times, as it clogged up with ground off steel,
but it did not take long to get a nice sharp edge on the new hole punch!

hole_punch_3.JPG
I then just tapped it to cut a nice round gasket/washer.

hole_punch_4.JPG
I had a hole punch the right size for the center hole

hole_punch_5.JPG
I just popped it in place, and it works REALLY well, not leaks that my pump cannot overcome!:thumb:

Hope this helps! :wave:
 
Top