Boring Delrin Bushing

Kroll

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Guys I installed a Delrin bushing in my pulley so now I need to bore it to size.Right now its about 1 1/4 so the opening is kinda small.I do have boring bars but they take inserts.This being some kind of plastic I figure the tool has to be real sharp so that would be HSS.Well I don't have a boring bar for HSS so what do I need to look for in boring bar and since this is a small opening I guess the cutting tool also needs to be small.Would that be say 1/4 x 1/4 HSS and a bar that is made for this size cutting tool?If you have any ideals and links to what I need please let me know.I have purchase from Shars before and they seem to have good prices,maybe something is there?Thanks guys
 
If the hole depth isn't too great, a boring bar can be made from a broken tap or a drill bit. For boring Delrin, you could probably get by with mild steel rod. An old rat tail or triangular file can be modified as well.
 
There are not tricks to bore Delrin, it works easily and with good finish, the tool, of whatever type should be sharp and with a small corner radius. Delrin is about the easiest plastic to work with, no stringy chips ----
 
Thanks guys,I wanted to ask this bushing cost me 76.00 so that kinda makes me nervous.But reading all the replys I will look around find something that can grind a sharp edge.
 
I would buy the largest cement nail that will fit the bill and grind the head for boring plastic.
Cement nails are very stiff. You can get an amazingly sharp edge on cement nails that is tough as .........nails.
 
"You can use one flute on a HSS endmill, just think of it as a boring tool and set the flute edge horizontal and at the right height."

I have used this approach as well when my standard boring bars were too big for the hole I wanted to bore out. I've used the method on brass, aluminum and plastic with good results. I was concerned that the large positive rake would be a problem with brass (which has a tendency to self-feed in some circumstances), but no problems so far.
 
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