Jimmie D wrote:
I want to make some fiberglass antenna parts that would probably most easily
be make by turning fiberglass rod in my lathe. Ive never done this before
and was wonder how rough fiberglass would be on the tools/lathe. I have a
piece of 1- 1/4 inch fiberglass rod I want to turn down to fit the inside
diameter of a piece of 1-1/4 inch tubing. Im thinking get a piece of square
stock and make a diposable cutting tool for this.

Jimmie


I've cut and machined a fair amount of Extren (pultruded structural
fiberglass composites) and things like glass-epoxy laminate over the years.

- cutting glass fibers makes tools dull in a big hurry, even carbide,
the wear rate is spectacular.
- diamond tooling survives quite well and isn't all that expensive
- or, just buy cheap tools and throw them away after a couple uses
(e.g. drill bits)
- the dust is quite obnoxious and abrasive, avoid getting it in the
ways or anything that needs high precision. lots of liquid coolant
helps keep the dust to a minimum
- breathing the dust is bad, getting it on your skin is bad, getting it
on your clothes is bad. Consider wearing one of those disposable tyvek
coverall suits. Try and keep the dust from spreading, because
inevitably, you'll pick it up later, and it itches, if nothing else.

- these are the reasons why machine tools used to machine glass or
carbon reinforced composites sell at a discount.. they wear out fast..
all those little abrasive particles grind away at all the precision parts.

Unless you're going to be doing a lot of it, you might be better off
just paying a machine shop that handles the stuff to do it for you.
Places that regularly machine laminates and composites have all the dust
collection stuff and tooling, and factor the wear into the price structure.

When I started working with composites at a former employer, they had
only done machining on conventional metals and plastics. After my
little foray into composites, they decided it wasn't worth it. Metal
scrap is easy to manage, little bits of glass fiber isn't.