I need a special purpose boring bar and have a simple question. I suppose I
could just try it and see what happens, but...

I'm thinking of making a steel bar, cutting an appropriate notch in the end,
brazing a piece of tool steel into the notch and grinding it as required.

I have a couple questions:

1. What will brazing do to the temper of the tool steel? Should I quench
it after brazing in water? Oil? (What kind of oil?)

2. I've been told that brazing won't adhere very well to tool steel. Does
anyone know for sure? Tried it before?

Thanks.

Jerry

if the bar is large enough you can make it hold small cemented carbide bits

when it is too small I just tig weld a piece of high speed steel on
the end of a bar , grind to desired size and use it ,

have done it for threading, grooving and other internal detail work where a
special was needed, in mild steel and 4140 mostly

"Jerry Foster" wrote in message
...
I need a special purpose boring bar and have a simple question. I suppose
I
could just try it and see what happens, but...

I'm thinking of making a steel bar, cutting an appropriate notch in the
end,
brazing a piece of tool steel into the notch and grinding it as required.

I have a couple questions:

1. What will brazing do to the temper of the tool steel? Should I quench
it after brazing in water? Oil? (What kind of oil?)

2. I've been told that brazing won't adhere very well to tool steel.
Does
anyone know for sure? Tried it before?

Thanks.

Jerry




Drill and ream "a hole" .001" so "oversize" crosswise in the bar near the
end. Tap a set screw hole in the end, on axis. Use a drill blank whose
diameter corresponds with the "hole".

Same idea, but broach a square hole for a lathe bit.

Randy

"Jerry Foster" wrote in message
...
1. What will brazing do to the temper of the tool steel?

Ruin it.

Should I quench
it after brazing in water? Oil? (What kind of oil?)

Use what the tool steel uses. Water for W1. Etc. Then temper around 350°F
for an hour.

2. I've been told that brazing won't adhere very well to tool steel.
Does
anyone know for sure? Tried it before?

Tool steel is 95% (except for special grades) mild steel, it works just
fine.

Use brass braze, quench immediately after the filler solidifies - or while
still molten if it'll hold in place (capillary action will probably secure
it nicely in a recessed pocket).

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

"Harold and Susan Vordos" wrote in message
...
If you have silver solder, make that your choice. Do not quench.

And anneal it in the process. Assuming he does indeed have common tool
steel, and not HSS. If it is HSS, silver solder is the way to go of course.

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

"Jerry Foster" wrote in message
...
I need a special purpose boring bar and have a simple question. I suppose
I
could just try it and see what happens, but...

I'm thinking of making a steel bar, cutting an appropriate notch in the
end,
brazing a piece of tool steel into the notch and grinding it as required.

I have a couple questions:

1. What will brazing do to the temper of the tool steel? Should I quench
it after brazing in water? Oil? (What kind of oil?)

2. I've been told that brazing won't adhere very well to tool steel.
Does
anyone know for sure? Tried it before?

Thanks.

Jerry



If you have silver solder, make that your choice. Do not quench. You can
also heli-arc the tool in place using silicon bronze filler. Either of
those procedures work fine.

Harold

"Tim Williams" wrote in message
...
"Harold and Susan Vordos" wrote in message
...
If you have silver solder, make that your choice. Do not quench.

And anneal it in the process. Assuming he does indeed have common tool
steel, and not HSS. If it is HSS, silver solder is the way to go of
course.

Tim

Thanks, Tim. Yeah, make sure you use HSS, not other types of tool steel.

Harold

Jerry Foster wrote:

I need a special purpose boring bar and have a simple question. I suppose I
could just try it and see what happens, but...

I'm thinking of making a steel bar, cutting an appropriate notch in the end,
brazing a piece of tool steel into the notch and grinding it as required.

I have a couple questions:

1. What will brazing do to the temper of the tool steel? Should I quench
it after brazing in water? Oil? (What kind of oil?)

2. I've been told that brazing won't adhere very well to tool steel. Does
anyone know for sure? Tried it before?

I have to ask, even at the risk of looking dumb -- have you considered one
of the import boring bars with square holes broached? The ones with the hole
at one end broached at 90° and at the other 45°? These are very inexpensive
and the ones I have purchased from Enco have been made very well even if
they were made in India. I have rarely been as happy with a purchase. - GWE

Jerry Foster writes:

I'm thinking of making a steel bar, cutting an appropriate notch in
the end, brazing a piece of tool steel into the notch and grinding it
as required.

See my page, "Making a Boring Bar for the Lathe":

http://www.truetex.com/boring.htm

It's the only way to go for specialized boring bar bits. You don't even
have to notch the end unless you plan to really abuse it.
Brazing or silver solder works fine.
Bugs

On Fri, 25 Mar 2005 00:31:20 GMT, "Jerry Foster"
wrote:

I need a special purpose boring bar and have a simple question. I suppose I
could just try it and see what happens, but...

I'm thinking of making a steel bar, cutting an appropriate notch in the end,
brazing a piece of tool steel into the notch and grinding it as required.

I have a couple questions:

1. What will brazing do to the temper of the tool steel? Should I quench
it after brazing in water? Oil? (What kind of oil?)

2. I've been told that brazing won't adhere very well to tool steel. Does
anyone know for sure? Tried it before?

I have made a number of special purpose tools by silver-brazing bits
of HSS to mild steel shanks. Bits of broken HSS slitting saws make
nice narrow parting tools and grooving tools for snap ring grooves. I
once made a form tool for making round-bottomed threads by
silver-brazing a steel ball to a shank and then grinding the top half
away to leave a perfect hemisphere. Made a boring bar similarly.
The application was a shop-made ballscrew. It was a little rough at
first. I filled it with 400 grit clover compound, ran it up and down
about 200 laps with a half-inch reversable electric drill. It put up
a fight at first, but got over it. After I took it apart, cleaned it,
lubed it and loaded it with new balls it ran very nicely indeed. The
trickiest part was the ball return tube, made of copper tubing.