[TowerTalk] Machining Fiberglass

[Kurt Andress]

Bill Coleman AA4LR wrote:
> 
> On 5/12/00 4:46 AM, Tom Wagner at tomwagner@mindspring.com wrote:
> 
> >
> >I have access to some inexpensive fibeglass rods.
> >Are there safety issues in machining fiberglass?
> 
> Yes!
> 
> Fiberglass, when worked, tends to emit teeny little sharp particles of
> shattered glass fibers. Not to mention the little sharp particles of
> shattered epoxy resin. You don't want to breath these. They will lodge in
> the lining of your lung and stay there forever. Wear a respirator (not a
> paper mask, a respirator) when machining. Fortunately, the particles are
> rather heavy, and don't tend to remain suspended in the air long. Clean
> up the resulting dust with a shop vaccuum.
> 
> >Is fiberglass hard on tools?
> 
> Yes! It tends to wear away tool surfaces quickly. Use sharp drills and/or
> blades.
> 

Good advice, here's some more....

Fiberglass eats high speed steel cutters for breakfast, lunch and
dinner.
It only eats carbide tipped cutters for breakfast.
Diamond coated abrasive cutters are the only thing it doesn't eat if
cutter heating is kept under control, otherwise the coating holding the
diamond bits on the tool goes away and the diamonds with it.

Plan on replacing or resharpening your HS steel cutters if you use them
on fiberglass. 
Very frequent resharpening during use is best, for drilling that's every
few holes depending on material thickness. This will allow you to save a
drill bit afterwards. If you go too long before resharpening, the
cutting edges on the cylinder get worn down and the thing becomes
unsalvagable at the original diameter. A tool grinding service can turn
it into a useful smaller size cutter.

-- 
73, Kurt, K7NV

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