Some lathes (like the Stubby) have cross drilled main shafts and this makes the use of vacuum adapters a challenge. I decided to make an adapter for my stubby this weekend. The adapter detailed below can be made from standard hardware store items, except for the double sealed bearing which you can get from Master Carr in a few days.
|I modified a design from the Fall Issue of Wood turning Design. The main design modifications consisted of the addition of a vacuum shaft and MT2 seal.The modified design assembly is shown to the right with individual parts detailed below.|
|Rotating adapter:made from standard 1/4 MIP inch threaded pipe, air fittings and a double sealed bearing. The right angle adapter is fitted with a nipple that is CA’d into the bearing and the other end is fitted with a standard air fitting. The fittings are Watts brass pipe fittings from Home Depots plumbing section and the bearing is 6384K49 from Master Carr.The 1/4 MIP x Close nipple [A-740, Watts] was mounted in a 3 jaw chuck and the threads turned to the ID of the bearing.One end of the nipple was then threaded into a FIP elbow [Watts A-727] and the other was then glued with CA into the bearing.The bearing assembly is pressed into the mortise in the outer hand wheel adapter after inserting the bearing seal. The bearing is secured with 3 screws that capture the outer ridge of the bearing and press it against the seal. The bearing could be epoxied into the mortise eliminating the seal and screws but I wanted to make the bearing replaceable.||Brubaker the movie|
|Bearing seal: made from non-slip shelf material. I got mine from Albertsons grocery store. It is a soft neoprene like material used to line shelves. You can also use neoprene PN9109K62 from Master Carr for any of these seals.|
|Hand wheel adapter (outer): made from MDF turned on waste block and a mortise that fit the bearing was turned on center with a 3/8 center drilled hole. The diameter of the hand wheel adapter should match your lathes hand wheel.|
|Hand wheel seal (inner): made from non-slip shelf material. You could eliminate this seal and just glue the two sections of MDF together. I wanted to be able to get to the Tnut (PN90975A059 from Master Carr) inside the assy if necessary.|
|Hand wheel adapter (inner): made from MDF turned on a waste block and bored with a 3/8 inch hole and a 1”x1/8 deep countersink on its inside surface. A Tnut is installed on center on the inner surface. This nut will receive the vacuum shaft when it is inserted through the headstock. I installed the Tnut on the lathe using a 3/8 all thread to get it centered in the 3/8 hole. I re-tapped the thread in the Tnut to match the 1/8 IP pipe thread (which amazingly was in my tap set).
Note: the Tnut must be countersunk below the surface so that the two halves of the hand wheel adapter can be fit together without interference.
|Hand wheel seal outer (outer): made from non-slip shelf material. The seal is glued to the outer surface with contact cement. This seal will be pulled tight against the hand wheel when in operation.|
|Vacuum shaft: to deliver the vacuum to the vacuum chuck this is a 1/8 IP “all thread lamp pipe” from HD PN70270 [Westinghouse] which is close to 3/8 inches in diameter. I installed a 3/8 diameter clear hose on the shaft to help prevent scratching the MT2 tapir when the vacuum shaft is installed in the headstock. I used a 30 inch all thread pipe and cut it to the size of my headstock.|
|MT2 Seal: the seal in the head stock taper is made from a #2 neoprene plug from Lowe’s [Hillman 13/16 x 5/8 x1] . Freeze the plug (that will make it hard for drilling) and then drill it with a Jacob chuck while it is jammed in the headstock. The MT2 seal is inserted on the shaft and secured with 1/8 IP lamp rod bolts and washers [Westinghouse, Home Depot PN70172]..|
In operation the vacuum shaft with the MT2 seal installed is pressed into the MT2 taper. While holding the shaft the hand wheel adapter is screwed onto the other end of the shaft until it is tight on the lathes hand wheel. Attach the vacuum hose to the rotating adapter and screw on the hand wheel adapter. Plug the vacuum shaft and check for leaks. Don’t be surprised if it really sucks 🙂
Don’t forget to visit the store where you will find some interesting books on wood turning!