Wednesday, April 30, 2014

Step #11: Drilling and tapping the garter and finger shoulders

In order to assure absolute alignment of the very small screws that retain the garters I decided to fabricate a single-use jig to clamp the garters to the fingers. I also decided to make the jig in two major parts. One is a sled that holds the finger and garter together and the other is a frame that is adjustable that allows me to set the exact, repeatable, center to center distance by sliding the sled left and right. I didn't want to trust repeatability to cranking the cross slide table the same for each finger setup.

See images below. It worked flawlessly even though it does look a bit nasty. oil, metal and wood just don't become all that pretty when you mix them.
Cutting the shoulder into the top of the finger for a flush garter fit

Garter fits just  right. I can take it all flush later if I want

Clamping sled. Not pretty but very accurate

Finger and garter clamped in place (forgot to photo it before drilling the garter holes)
Drilling the countersink. Note gap on left to repeatably shift part for other hole
Here you can see the whole jig with the adjustable leg on the frame. I made it so that I could drop the sled in place, push it to one side and use a micrometer to set the gap to exactly the center to center difference between the holes I wanted for all the garters. All that remained was to center the drill over the first hole, clamp and drill, loosen and slide to the other side, and then clamp and drill. Rinse and repeat for all three sets and voila!
Jig frame with adjustable leg for setting gap/ctr to ctr distance
Drilling through the countersink holes into brass. Note quick clamp bar holding sled to frame
All that remained was to tap the holes in the brass fingers and install the screws to secure the garters. and assemble the finger sub-assemblies.
All parts for finger sub assembly completed
Assembled finger sub assemblies ready to install and test!
 I made sure it all moved freely fully assembled, then disassembled it all for final finish and polish. I put it all back together and the steady rest was done! I had a lot of fun making it and it didn't drag on too long. It works like a dream and I've already employed it on my next project. I think I'm going to install some stainless micro roller bearings at the end of the fingers soon. The Brass works great but I don't want to score the brass parts I might use this on.

Finished Mowrer Steady Rest!

Back of the completed Mowrer Steady Rest

Top pivoting open
Fingers fully withdraw into frame
Mounted on by lathe bed. The red reflection from the wall makes it look like copper!

Steady rest opened up to swap multiples in and out with ease!

 If you decide to make one, I hope you have as much fun as I have. There's lots of places you could make different design choices like washers, style of knob on the lead screw (knurling anyone?), style of lock down nut, how much finishing to do on the frame, etc....

Please keep in mind that I don't supply the screws or hardware or bar stock for the fingers, the lead screws, the hold down screw and nut or the pivot and lock.

All of that is very simple to find online or even just through ebay. Feel free to email me with any questions you might have. I want you to have success making this and would love if you make any changes to see what they are. I might even post them here!


Cheers. Kevin Mowrer

No comments:

Post a Comment

Indexing tool for watchmakers lathe

Hello friends Today I completed the indexing tool for the watchmakers lathe. I've had on my wish list making some very fine rope knurl ...