Folks -

Okay, I am cutting DTs in some oak veneer ply using the Stott's setup... I
have two routers, one with the DT bit, the other with the pattern bit, and
everything is adjusted so the joints slide into place with magnetic
attraction - beautiful.... they won't be exposed, which is good - because of
tearout in the ply.

I am revisiting this issue from an earlier post a few days ago. Both bits
are new. I am taking a pull-saw and cutting on either side of the pin to
make things easier, but am still getting fractures between the veneer
laminations..

I got to thinking about it, and what I need, I think is a spiral (for a hand
held router would that be an upcut bit??) pattern bit. Does anyone make
such a beast - I've poked around in MCLS and Price Cutter but haven't seen
anything.

My reasoning is that a spiral bit would give a smoother cut and place less
stress on the thin ply layers than the straight cutting edge of a regular
pattern bit.

Anyone heard of such a thing? Does my logic check out? I'd appreciate your
feedback.

John Moorhead

I have heard of using the spiral upcut bits for cutting mortise and
tenons, and they are probably the right bits for the job. This problem
has some parallels in metal machining, and they make roughing end mills
with a spiral fluting that does the job magnificently. As for a
source, I would try the Whiteside line of bits marketed by Woodcraft
(and probably others). Check in the Woodcraft catalog.

WW88 -

Spiral bits, no problemo - what I *need* is a spiral *pattern cutting* bit -
a half-inch bit, quarter inch shank, with a bearing at the top of the bit.

Any ideas?

John


"woodworker88" wrote in message
oups.com...
I have heard of using the spiral upcut bits for cutting mortise and
tenons, and they are probably the right bits for the job. This problem
has some parallels in metal machining, and they make roughing end mills
with a spiral fluting that does the job magnificently. As for a
source, I would try the Whiteside line of bits marketed by Woodcraft
(and probably others). Check in the Woodcraft catalog.

"John Moorhead" wrote in message
m...
WW88 -

Spiral bits, no problemo - what I *need* is a spiral *pattern cutting*
bit - a half-inch bit, quarter inch shank, with a bearing at the top of
the bit.

Any ideas?

John


Spiral bits are all solid carbide AFAIK. Also, the largest diameter shown
for 1/4" shank is 1/4".

http://www.infinitytools.com/products.asp?dept=1089

Flush cut do the job? The flutes are not straight.
http://www.infinitytools.com/products.asp?dept=1024

Ed -

Boy, thanks for the link.... Got some good info, but alas.... They have a
"downshear" template bit, unfortunately.... the minimum diameter for a
top-bearing downshear bit is a 3/4" cutter, and I need 1/2"... I just may
be talking out my.... hat and it just doesn't exist... but I think that my
theory as to why I am getting the "fracturing" of the plies is correct. I
only have 4 more to cut, and DTs in ply are pretty rare work for me, so it
may be just as well. Even tho' the joints won't show, and even tho' it'll
be plenty strong and all, I just don't *like* having a crappy joint in a
project. Now I'll probably start thinking about ways to patch in for the
damaged pins, but that'd be over the top.

Again thanks for the site, I am going to keep those downshear bits in mind
next time I need to replace a larger pattern bit.

John Moorhead
"Edwin Pawlowski" wrote in message
m...

"John Moorhead" wrote in message
m...
WW88 -

Spiral bits, no problemo - what I *need* is a spiral *pattern cutting*
bit - a half-inch bit, quarter inch shank, with a bearing at the top of
the bit.

Any ideas?

John


Spiral bits are all solid carbide AFAIK. Also, the largest diameter shown
for 1/4" shank is 1/4".

http://www.infinitytools.com/products.asp?dept=1089

Flush cut do the job? The flutes are not straight.
http://www.infinitytools.com/products.asp?dept=1024

John Moorhead wrote:

WW88 -

Spiral bits, no problemo - what I *need* is a spiral *pattern cutting* bit -
a half-inch bit, quarter inch shank, with a bearing at the top of the bit.

Any ideas?

John

Since you're using Stotts, is it possible to make your pattern oversized
to compensate for a "guide" (I should go out to the shop and see
what's on my PC set to use the right term). Then you could use whatever
bit you wnat as long as it has a corresponding "guide".

Or, you could sandwich your ply between sacrificial pieces of
ply to avoid tear out.

Just thinking "out loud".

charlie b

"charlie b" wrote in message
...

Since you're using Stotts, is it possible to make your pattern oversized
to compensate for a "guide" (I should go out to the shop and see
what's on my PC set to use the right term). Then you could use whatever
bit you wnat as long as it has a corresponding "guide".

Or, you could sandwich your ply between sacrificial pieces of
ply to avoid tear out.

Just thinking "out loud".


That's the key. I won't use any but spiral bits in my Leigh, even though I
had to fiddle and mark to get the settings. The shear does a good job,
even, with slow approach, in plywood. Box joinery too.

In article ,
charlie b wrote:

Just thinking "out loud".

Keep it down over there, will ya? I can't hear myself think!

On Sat, 16 Apr 2005 00:39:20 GMT, "John Moorhead"
wrote:

Folks -

Okay, I am cutting DTs in some oak veneer ply using the Stott's setup... I
have two routers, one with the DT bit, the other with the pattern bit, and
everything is adjusted so the joints slide into place with magnetic
attraction - beautiful.... they won't be exposed, which is good - because of
tearout in the ply.

I am revisiting this issue from an earlier post a few days ago. Both bits
are new. I am taking a pull-saw and cutting on either side of the pin to
make things easier, but am still getting fractures between the veneer
laminations..

I got to thinking about it, and what I need, I think is a spiral (for a hand
held router would that be an upcut bit??) pattern bit. Does anyone make
such a beast - I've poked around in MCLS and Price Cutter but haven't seen
anything.

My reasoning is that a spiral bit would give a smoother cut and place less
stress on the thin ply layers than the straight cutting edge of a regular
pattern bit.

Anyone heard of such a thing? Does my logic check out? I'd appreciate your
feedback.

John Moorhead


Not sure if they exist, but also not sure that this would solve your
problem. The problem with ply is the alternating grain; if you have ply
with voids, that's going to exacerbate the problem further. You could
try a non-pattern spiral bit, if you've got one, just as an experiment to
confirm or deny the theory.
You *might* have better luck trying to set up things such that you could
use a backer board on all cuts. I'm trying to picture how one could make
this work on a dovetail jig and I'm not sure it will work.
The Leigh DT jig manual gives specific warnings about trying to DT
plywood, citing the specific problem you describe.




+--------------------------------------------------------------------------------+
The absence of accidents does not mean the presence of safety
Army General Richard Cody
+--------------------------------------------------------------------------------+

"John Moorhead" wrote in message
...
Folks -

Okay, I am cutting DTs in some oak veneer ply using the Stott's setup... I

snip

make things easier, but am still getting fractures between the veneer
laminations..

snip

I got to thinking about it, and what I need, I think is a spiral (for a
hand
held router would that be an upcut bit??) pattern bit. Does anyone make
such a beast - I've poked around in MCLS and Price Cutter but haven't seen
anything.

My reasoning is that a spiral bit would give a smoother cut and place less
stress on the thin ply layers than the straight cutting edge of a regular
pattern bit.

John...

I've seen spiral bits with pilor bearings (at the end) but can't remember
where (or whether they were up or down spiral - but will guess they were up
spirals.)

If you're cutting all the way through the plywood, you might try a
compression spiral (which is an upcut on the bottom and a downcut at the
top).

If you're not cutting all the way through the plywood, you'll probably get
best results with a down spiral because there is less opportunity for layers
to move at the cut boundary. A straight bit should do /almost/ as well, and
an up spiral will maximize tearout. That's been my experience, anyway.

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
www.iedu.com/DeSoto/solar.html

On Sat, 16 Apr 2005 00:39:20 GMT, "John Moorhead"
wrote:

Folks -

Okay, I am cutting DTs in some oak veneer ply using the Stott's setup... I
have two routers, one with the DT bit, the other with the pattern bit, and
everything is adjusted so the joints slide into place with magnetic
attraction - beautiful.... they won't be exposed, which is good - because of
tearout in the ply.

I am revisiting this issue from an earlier post a few days ago. Both bits
are new. I am taking a pull-saw and cutting on either side of the pin to
make things easier, but am still getting fractures between the veneer
laminations..

I got to thinking about it, and what I need, I think is a spiral (for a hand
held router would that be an upcut bit??) pattern bit. Does anyone make
such a beast - I've poked around in MCLS and Price Cutter but haven't seen
anything.

My reasoning is that a spiral bit would give a smoother cut and place less
stress on the thin ply layers than the straight cutting edge of a regular
pattern bit.

Anyone heard of such a thing? Does my logic check out? I'd appreciate your
feedback.

Depending on what router you've got, a set of guide bushings should
work with any spiral bit- then you don't have to go digging for a
pattern bit.

Aut inveniam viam aut faciam

John Moorhead wrote:

I got to thinking about it, and what I need, I think is a spiral (for a hand
held router would that be an upcut bit??) pattern bit. Does anyone make
such a beast - I've poked around in MCLS and Price Cutter but haven't seen
anything.

Someone does, because I've seen David Marks use one on Woodworks.

Whiteside seems to make 'em:

http://www.woodcraft.com/family.aspx...&FamilyID=8005

-j