On Thu, 21 Sep 2017 17:57:24 -0400, "Jim Wilkins"
wrote:
"Howard Beel" wrote in message
news
"Jim Wilkins" wrote in message
news
"Howard Beel" wrote in message
news
"Jon Elson" wrote in message
news
Howard Beel wrote:
I have found that most slitting saws have some runout and
usually need
a touch up when mounted in the arbor. For some reason there
always
seem to be a few teeth that are higher than the rest. Some of
the blades
i indicated were 15 thou out of round and i sent them back to
the vendor.
After mounting the saw in the mill i indicate it and mark the
high teeth
then use a dumore tool post grinder to knock down the high
teeth.
I like the peterson expanding flush mount arbors and robbjack
arbors.
Yes, I can certainly hear the runout as a zing-zing-zing as the
spindle
rotates. It doesn't seem to hurt the operation or affect surface
finish
much in the groove. So, I just live with it.
My guess is these things are punched out of blanks, rather than
machined and
sharpened on an arbor.
Jon
It would be intresting to how the saws are made. Since they are
made of HSS
i don't think they are stampings. Maybe the hardened blanks are
stacked and
ground on a specialized cnc grinder, grind a bunch of the same
size saws all
at once?
Best Regards
Tom.
I turned and milled the shank end of a 3/8" HSS drill bit into a
1/4" hex with retention groove to snap and lock into an extension
shaft. It cut easily with HSS tooling.
-jsw
All the HSS drills i have run into have soft shanks. Only the flutes
are HSS.
My collection of big drills were originaly 4 and 5 MT that i
purchase cheap
because there is no hobby market for them. Generaly you can buy them
at
industrial auctions for scrap prices. Just turn down the shanks to
size you
need. I use a collet chuck to hold them so the shanks don't mungged
up.
Best Regards
Tom.
I understood that the drills are HSS all over, but the shank remains
annealed for better grip.
Yes, and they're a lot less prone to shatter when they're deflected
sideways.
http://www.zianet.com/ebear/metal/heattreat5.html
"mica", not "mice".
Note how long it takes to anneal HSS -- 2 to 8 hours.You can't do it
with a torch.
The MT2 tailstock on my lathe and B&S 7 spindle on my mill limit drill
bit size to around 3/4" for heavy cuts, 1" by going slowly. I cut
larger holes by boring or with a hole saw.
-jsw
--
Ed Huntress