dovetails in baltic birch... the problems continue

[James Washer]

I've been trying to build some drawers using 1/2in baltic birch plywood,
using my Leigh D4-24 jig.

I had a terrible problem with tearout using the Leigh supplied bit
cutting the tails.. A web search led me to believe that I'd have better
luck with a better bit..

Today I tried with Whiteside and Jesada bits, and things are still
unacceptable. I get large flakes of plywood ripped away..

So, what am I to do now? Backer boards? Is this possibly 'bad' baltic
birch? Is it likely my technique (or lack thereof), etc etc.

thanks
- jim

[Kim Whitmyre]

So, what am I to do now? Backer boards? Is this possibly 'bad' baltic
birch? Is it likely my technique (or lack thereof), etc etc.

---------------------------
Make sure it's actually Baltic, as in Finnish, Birch. I've made drawers of
it before and did not have any tearout. I've got a Woodhaven half-blind
dovetail jig that uses an Amana bearing-guided bit.

Kim

[Dwight Roberts]

I tape all four faces before routing plywood and seem to get good dovetails
everytime.

Dwight

"James Washer" <was...@trlp.com> wrote in message
news:3C3E6D99...@trlp.com...

[Matt Gradwohl]

Try pre-cutting with a straight bit so that the dovetail bit removes less
material.
Go slower.
Check your RPM.
Put blue painters tape on the wood first.

"Kim Whitmyre" <don...@mminternet.com> wrote in message
news:u3ssqe3...@corp.supernews.com...

[James Washer]

Ok, I'll give the tape a shot...
As for 'going slower'.... do you mean 'moving' the router slower through
the template, or using a slower rpm speed?

And yes, I think it's 'baltic birch'... it's certainly birch, 5x5ft
sheets, fine ply's, etc etc

- jim

[Eric Garcia]

Try the backer board. I was able to cut box joints on a table saw in 1/8"
baltic birch using a sacrifical piece of ply behind.
Good luck
Eric

[Lew Hodgett]

James Washer writes:

> I've been trying to build some drawers using 1/2in baltic birch plywood,
> using my Leigh D4-24 jig.

<snip>

Can't offer any specific solution to your problem, if you are using a sharp
bit operating at the correct RPM, other than to suggest a slower feed rate
and/or a backer board.

Having said that, all "Baltic Birch" is not Finnish Birch, which is what you
want. It uses exterior glue.

Russian Birch often uses interior glue and is definitely lower quality, and
lower cost.

The latest one I have seen is the other day.

My supplier stopped by the yard with a piece of 1/2", 9 ply, with US
produced veneers and Chinese cores that was assembled in China.

A dog's hind leg has less curves.

It was pure garbage. Low cost, but still garbage.

HTH

--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures

[brian lanning]

James Washer <was...@trlp.com> wrote in message news:<3C3E6D99...@trlp.com>...

I'm just now finishing up a project with through dovetails in 1/2"
(not baltic) birch plywood cut with a pc 690 and a leigh d4. I had
problems, but I was able to solve most of them. The drawers came out
fine. Here's what I suggest:

Definitly use backer boards. You may want to always use them anyway,
but I'd say they're definitly required with ply.

Use thicker pins if you can. Mine were only about a quarter inch
thick though and I was able to make it work.

Technique is everything. When cutting tails, I do a relief cut from
right to left across the face of the board. Sometimes, I may lift the
router out and make another relief cut right to left if I think it
wasn't deep enough. You want to cut through the first ply with this
cut. Then I plunge the bit straight through along the left guide pin
all the way through into the backer board. Then I make a similar
relief cut from left to right along the back of the board cutting
through the backer board, then I pull the bit out on the right side
along the right guide. Then I clean out the rest. Go very slow as
the bit cuts through the surface at the sides. This technique got me
perfect tails and so-so pins. I switched to a spiral upcut bit for
the pins instead of the straight cutting bit and it helped a little.
Same technique for cutting pins as tails. In a few cases, I lost
pieces of ply from the pins. Like one of the layers in the middle
would fall out. I just glued it back in. You may have to clean them
up a little with sand paper or a box knife. The joints are perfectly
square and look very good now.

brian

[NOSPAMBOB]

Backing solved the problem for me.

In article <3C3E6D99...@trlp.com>, James Washer <was...@trlp.com> writes:

>I had a terrible problem with tearout using the Leigh supplied bit
>cutting the tails.. A web search led me to believe that I'd have better
>luck with a better bit..

Name works for E-mail

[mke...@nc.rr.com]

On Thu, 10 Jan 2002 20:44:09 -0800, James Washer <was...@trlp.com>
wrote:

Always use a backer board. Birch is fairly brittle to begin with, and
I suspect the way all rotary cut veneers are processed weaken them
slightly allowing the fibers to tear out more easily.

-Mark