Thursday, July 15, 2010

bronze bearings

making some test pieces for the bromke rack- bronze bearing in a steel journal.

i used a regular drill bit to open up the steel round bar to 3/8, but i think when i make them for real i need to bore it, for closer clearance between the bearing and journal. the drill bit cut it a little oversize.

that leaves me with another little project, make a boring bar holder for the lathe toolpost, or an easier but less versatile method i can grind a small enough boring bit out of HSS.


3 comments:

alex wetmore said...

The drill shouldn't cut oversize if you are taking a very light cut (and the tailstock is aligned). I'd cut 1/64" under, then do a very light final cut to your size.

D n L said...

it is only oversized by a few thousandths. since i was just taking practice cuts i wasnt really too concerned with the final ID of the journal.

next one i make im gonna creep up on the final ID, and see how that measures. if its close enough than i will stick with using the twist drill, if not ill probably bore it.

im shooting for a clearance of .001".

D n L said...

alex, i made a few more of the journals. i took your advice and removed most of the material, the took a light final cut. more than 1/64 final cut bc i didnt have that drill bit, so the finshing cut was 3/64. a lot smoother than going from a quarter inch to 3/8!

im happy with the result, the hole came out much nicer.