Re:Lathe How To Site
- Re to cat
"I may be wrong.."
You are not wrong. Carbide has a near zero top rake while HHS ususlly had 10 to 20 degrees. With carbide you usually have the top of the bit parallel to the shank and have little chance to get it level without a zero angle holder.
My tool holders are 7 degrees and 14 degrees. As to tool holders, they sell like gold on ebay. One just passed for a 12" straght holder used for about $25 and then about $9 for shipping. I got mine at flea markets and did not pay much. (I'm cheap and old)
Carbide bits have gotten quite cheap compared to the old days. I saw a thing on TV like "how it is made" or such and they brazed carbide to a steel holder with induction heat and it took about 2 seconds. The flux and solder powder were put in with a needle, just a drop and quick heat and that is that. Automation makes it cheap and reliable. Grizzly sells 20 (1/4") for $14.95. For that, I use them and toss them.
--- In firstname.lastname@example.org, catboat15@... wrote:
> I have several armstrong bit holders gathered over several years of junk
> shopping. Some have the square hole for the bit at an angle and some
> present the tool bit straight on to the work.
> I may be wrong (Sure would not be even the second time for that) but I
> always figured the straight slotted bit holders were for carbide inserted bits.
> Where I have used those holders that don't have a slope to the square hole
> is for carbide bits brazed onto a holder where I use those for things like
> train wheels of cast iron. The carbide cuts through the molding sand and
> hard crust on the castings. Then change to normal HSS bits for finishing up
> the wheels to dimension.
> When doing something like this hang a magnet in a plastic baggy near your
> cutting site to attract a bit of the cast iron black powder that comes off
> as swarf. That stuff gets into everything.
> [Non-text portions of this message have been removed]