Clamping a small part for drilling
#1
10-12-16, 04:41 PM
Clamping a small part for drilling
I'm making kind of a bushing and I have to enlarge a hole in a nylon spacer. I did one of two well enough but I damaged my clamps because the spacer spun against the rubber of the clamp. How would you clamp a 3/8" diameter spacer to enlarge the hole? I just tried a small file that I could fit about 2" into the hole but it seemed very slow and it will probably quickly clog the file if it makes any progress at all.
#2
10-12-16, 05:07 PM
Member
There is no great way to hold it unless you have a lathe.
Even then it would be a challenge.
I might have tried to find a bushing with the right size hole.
McMaster Carr is one great source for things like this.
Even then it would be a challenge.
I might have tried to find a bushing with the right size hole.
McMaster Carr is one great source for things like this.
#4
10-12-16, 05:19 PM
Member
Not a great plan.
A three jaw chuck will not hold it evenly.
A drill will make an oval shaped hole.
Need a reamer for a really round hole.
What the spacer for, how accurite does it need to be?
A three jaw chuck will not hold it evenly.
A drill will make an oval shaped hole.
Need a reamer for a really round hole.
What the spacer for, how accurite does it need to be?
#5
10-12-16, 06:05 PM
It doesn't have to be very accurate. I want to put a 1/4" bolt through a 1/2" threaded hole without damaging the threads in the 1/2" hole and without too much wiggle room. This is for an exercise bike. Sometimes I'll be screwing a pedal in the 1/2" threads but when I'm using the crank shortener that I'm building I'll be using that undersized bolt.
#7
10-12-16, 06:17 PM
Member
Still does not make much since.
Why not just use stacked up steel washers?
I can see a 1/4" bolt just shearing off being used like that.
Why not just use stacked up steel washers?
I can see a 1/4" bolt just shearing off being used like that.
#8
10-12-16, 06:32 PM
Originally Posted by Tolyn Ironhand
Drill a 3/8 hole in a piece of wood. Cut the wood in half through the center of the 3/8 hole. Now you can just clamp the wood.
I can see a 1/4" bolt just shearing off being used like that.
#9
10-12-16, 07:13 PM
OK, so, I'm afraid of the 1/4" bolts I was going to use. I'm going to use 1/2" bolts that actually fit the threads. No need for the nylon bushings after all...now I have to shop for good quality 1/2" fine threaded bolts. One standard and one with left hand threads. Ugh...
EDIT: I'll go ahead with the 1/4" bolt for now. No way will it break in the first week, and I'll keep an eye on my father. If it works out, I'll upgrade to a 1/2" bolt.
EDIT: I'll go ahead with the 1/4" bolt for now. No way will it break in the first week, and I'll keep an eye on my father. If it works out, I'll upgrade to a 1/2" bolt.
Last edited by Borad; 10-12-16 at 08:48 PM.
#10
10-13-16, 05:38 AM
Group Moderator
I would bore a hole through the existing crank for the new bolt location. With your contraption it will be difficult to keep the bolt perpendicular. The hole in your steel plate will soon wallow out unless you find a way to securely hold it in place. You can weld the head of the bolt or install a nut on the other side of the plate to tighten the bolt onto the plate. That would also provide the spacing you're trying to do with a plastic spacer.
