Subject: Help with 7 inch bench top shaper

From: [email-masked] (Daryl Bender)
Date: Thu, 05 May 1994 17:31:54 -0500

In article <[email-masked]>, [email-masked]
(LrandolphL) wrote:

{Other Stuff}
> 
> 3.  Don't use more stroke length than you need.
> 
The reason for this is not immediately clear but what happens is you get an
edge effect. The cause is a minute plunging of the cutting tool once it
enters the work. In 1/16"- 1/8" (stroke not depth) it will settle out.  In
fact the edge effect will occur any time the cutting tool approaches the
work at a rapid speed. I have found that like (LrandolphL) wrote, set your
stroke length slightly in excess of your part. It is even better to set it
up so that once the tool JUST clears the part on the return stroke it
starts it's forward stroke. By changing directions JUST before the part,
the entry speed of the cutting tool is as slow as can be and the edge
effect is minimized.

-- 
Working, but not speaking for BNR.

---

From: [email-masked]
Date: Thu, 12 May 94 20:25:13 -0500

Also if you grind the tool such that you have about 20 degrees angle on
the base of the tool -- on the leading edge -- less of the tool enters the
work initially as the tool progresses across the work. That is, you get
a shaving cut. And you want lots of side rake -- at least 20 degrees for
steel -- and essentially no top rake. I find about 6 degrees front and
side clearance is plenty and you keep enough meat under the cutting edge
to keep the tool alive. About 1/4" daylight before the cut and 1/2" after
is sufficient. But the tool angles are the main thing to eliminate the
whack when the tool meets the work. (It would be easiest to think of this
like this. Say the table is moving left to right so you want a 'left hand
tool'(in the lathe sense). The tool would be ground to look like:  \_
with the '\' at about 20 degrees from the base. Of course you need
enough clearance under the '_' so it doesn't rub, but just a bit is
fine. As the tool first meets the work, it meets it higher on the '\'
to take a lighter cut. As the work moves under the tool, left to right,
more and more of the '\' part of the tool meets the work, but the part
of the tool that meets the "vigin" part of the work is still higher on
the toolbit for a lighter cut. I hope this makes sense. I have planed
stuff on my shaper with tools ground this way and it looks like they'd
been under a grinder.) If you work to a shoulder (this is HARD with a
shaper!), you use a tool much like I'm describing and then finish with
vertical tool and then a horizontal tool. This is probably why there are
no more shapers used anywhere but our basements! But if you want to make
something flat and smooth, you about can't beat them. IMVHO.
 
Charlie