I bought a set of 3/4 shank carbide inserted boring bars.
I have two of them with broken tips due various mistakes I made.
I was wondering if it is possible to get new carbide inserts and braze
them in.
I hate to buy a new set as these are short shank boring bars and are very
handy in some tool setups.

--
don paolino

desperado writes:

I was wondering if it is possible to get new carbide inserts and braze
them in.

http://groups.google.com/group/rec.c...56a9ade678de01

"desperado" wrote in message
...

I bought a set of 3/4 shank carbide inserted boring bars.
I have two of them with broken tips due various mistakes I made.
I was wondering if it is possible to get new carbide inserts and braze
them in.
I hate to buy a new set as these are short shank boring bars and are very
handy in some tool setups.
--
don paolino

Sure! Also, concider HSS chunks for special uses.

This is great to know!

But in looking at some chinese tooling, it sort of looks like brass/bronze
brazing rod was used. Mebbe even the fluxless stuff that the hvac peeple
use??
I would imagine the gold coloring on some carbide inserts should be ground
off?
--
Mr. P.V.'d
formerly Droll Troll
"Richard J Kinch" wrote in message
. ..
desperado writes:

I was wondering if it is possible to get new carbide inserts and braze
them in.

http://groups.google.com/group/rec.c...56a9ade678de01

Yup, I do it all the time for special function bits. Considering the
cost of some of the bits on the market it is hardly worthwhile for
standard bits.
Bugs

It could be brass /bronze which could contribute to the breakage. It
could be silver braze alloy corroded with age.

Sweat the old one out with a torch. Try not to burn the braze alloy.

The only problem may be with the new insert. Not all carbide wets
well. Put a good amount of flux on the new insert with a cut bit of
wire and heat it. If it flows out well then it is good.

tom

Proctologically Violated©® writes:

But in looking at some chinese tooling, it sort of looks like
brass/bronze brazing rod was used. Mebbe even the fluxless stuff that
the hvac peeple use??

I don't know that the color appearance is much help identifying an alloy.
The pricey 45 percent silver stuff still has a gold or brass color.

I forget where I researched this, but the cadmium and high silver alloy is
said to be critical to getting a shock-resistant braze on carbide. The
more common HVAC rods I presume would be more prone to snap off.

I have used the silver/cadmium rods, with the Allstate S-200 flux, on a
number of hand and power tools, and it has always wetted easily, filled and
filleted nicely, and held up superbly, with nothing more than Turbotorch
propane/air flame.

Probably on our web site. (We have a new version of our book Building
Superior Brazed Tools.) Our specialization is in high end applications
such as very narrow saw tips in mills, oil well heads, satellites, etc.
You are correct that the choice of alloy can make a huge difference.

However less expensive alloys can also work very well as the need for
bond strength and impact resistance drops. Arguably you need greater
strengths for a saw tip than for a braze joint in an air conditioning
system. Depending on the braze area (the bigger the better) and the
amount and direction of the force applied a much less expensive alloy
can be suitable.

Tom

writes:

Probably on our web site.

Yes, that's it:

http://carbideprocessors.com/Brazing/book/