RE: [7x10minilathe] Re: 60 degree thread gauge
MessageWell sirs I was cutting threads in 316 stainless like nobodies business. 20RPM is too low for the MicroMark. I had to cut at 100 RPM more or less. Used the crossfeed at 29 deg, and darn if it all wasn't coming together real nicely..........then I did something stupid, and broke my only carbide bit for threads. I went and used it like a cutoff bit and the stock rode up on it and made a mess. Very few people have my capacity fro stupidity.I was looking at MSC for a new carbide, and found there are 'industry standard' bit types, and material grades.....C2, C5, C6, and C7. Under Cutting tools -> tool bits -> brazed tool bits, you get down to the 5/16 bits for the 7x. Darn it though the 'Industry Standard Number', and 'Style' seem to be two different things, and neither of them just says '60 degree thread cutting bit'. Any enlightenment out there as to where the industry standard types are described?Thanks in advance,JB-----Original Message-----
From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of Ian Foster
Sent: Saturday, April 28, 2007 12:56 AM
Subject: [7x10minilathe] Re: 60 degree thread gauge
It would be wise to steer clear of stainless unless you particularly
need its qualities. OTOH I have turned some stainless with excellent
results; it was very hard on my taps. IMHO good steel is the easiest
metal to to turn. See if you can get some 12L14 from your supplier,
this is a free machining steel because it includes a higher proportion
of sulphur. 1018 and 1020 which are common mild steel grades machine OK
but 1214 is the most rewarding wrt finish.
If you are in a hurry the hardware store stuff can be pressed into
service according to my earlier comments. You spoke of it taking a long
time to turn down. I use HSS tooling almost exclusively and can take
1.0mm (40thou) cuts easily.
One good turn deserves another.
- Question: There are four scales on a threading tool center gauge. They
are marked 14, 20, 24, and 32. I assume they are for measuring pitch?
FYI.....Harbor Freight has that nice lathe bit grinder on sale.
The point of the HF tool grinder is that it is designed to grind lathe
tools. It uses plate mounted wheels where you grind on the side of the
wheel, not the face. The tables can be set for cutter relief angles
and the sliding protractor sets for tool angles and it has a drip
water cup. This type of grinder usually comes with green wheels which
can be used for carbide or steel though it is a bit soft for steel.
You can also get wheels for steel and diamond wheels for super
finishing carbide. With other types of grinder getting the right
angles on a tool are chancy, with this type they are easy, I grind all
my CNC tools on one of these.
Long Beach, CA