Project of the Month Winner
- Aug 25, 2007
- Reaction score
Nice, Ken! What size are the magnets you used?
This is almost 10 years later from your post. Do you have an ER chuck now? The ER chucks are one of my priorities. I have finished an ER 25, am currently finishing up a 32 and have the stock ready for a 40 and a 50. I just discovered the 50 and bought the nut but had a difficult time finding any actual collets. Found some expensive ones--ones that retired person's budget cannot stretch to--then finally found a single vendor with "China-like" prices.Got the four cylinder assemblies finished.
I "cheated" the three drilled holes in the cylinder heads by simply placing them on the cylinder at the last drilling & tapping position (last post) and spot drilled the head in-situ. I then drilled the spot 2mm on my drilling machine and returned it to the cylinder - fitted it in place with a M2 cap screw, 120° out and spot drilled the next hole etc. etc. - saved on having to mount and pitch drill each one.
Made the big ends from the smallest barstock possible by first drilling and reaming the bore eccentrically on the lathe with the 4 jaw.
Then transplanted the 4 jaw to the rotary table and milled the profile and drilled the holes. Back to the lathe for parting off.
Since I don't have an ER collet chuck I turned the rods in a drill chuck I have mounted on a shank (an old shockabsorber rod which has the correct 1/2"20 UNF thread - practically made for the job) mounted in my 4 jaw.
Next job the main body which is a maze of cross drilled holes.
Have you eveer taken apart an old hard drive and retrieved the magnet? There is a metal, must be glued, I suppose, that is about 2mm thick on the magnet. The odd thing is that the magnetism does not penetrate that metal. So one ends up with a magnetic part that is magnetic on one side only. (To this point, I only knew about one material which is "anti-magnetic", which I thimk is Bismuth, used to be about 60$/kilo.) I'm thimking, one could use a piece of that metal, maybe, to isolate the magnets from the iron or steel. Might work.The main body is mild steel with bronze bushes for the trunnions, the magnet is a press fit in the bronze to help isolate it magnetically from the body.
The drilling will also be tedious and I will need to be very carefull at the breakthrough points - I'm thinking of pushing a wire through the cross hole to prevent snatching as the drill goes through.
Anybody got any comments on that ?