dovetail jig and baltic birch - Woodworking Talk

338reddog · 10-29-2008, 10:15 PM

I need some advice
I am making some drawers using baltic birch and my jet dovetail jig when I make the first pass across the face the wood splinters.Some of the slinters as long as an inch. What am I doing wrong? Is this the nature of baltic birch.

mics_54 · 10-29-2008, 11:59 PM

I am suspecting a dull router bit. Guessing.

GeorgeC · 10-30-2008, 06:13 AM

Quote:

Originally Posted by mics_54

I am suspecting a dull router bit. Guessing.

ditto. Plus to rapid a pass.

G

**TexasTimbers** · 10-30-2008, 09:16 AM

I'm on the same bandwagon, but even go a little further. A brand new chinese bit may still splinter plywood a little. A very high quality American made bit may eliminate the problem.

If not, you can sandwich the piece between two 1/4" boards if you can make it all fit in the jig. This will eliminate the tear out for sure provided the sacrificial boards are flat against the exit sides of the workpiece where the bit .

Another trick is to slowly enter the workpiece from all four sides of the cut instead of entering the cut and exiting straight through. You usually can't do this with low quality bits because even new out of the box they can burn plywood, especially if your RPMs are too high.

Puumies · 10-30-2008, 12:46 PM

Previous answers are probably right, but if I may add one thing. Is it kiln dried birch? I use quite a much birch and I've noticed that naturally air dried birch is easier to work with. Kiln dried birch splinters far more than naturally dried.

Pauli

**TexasTimbers** · 10-30-2008, 01:10 PM

I probably made an assumption I shouldn't have, but I assumed he is referring to Baltic Birch plywood when he mentioned making drawers with Baltic Birch.

I haven't heard of anyone using much solid BB stock here in the states. Doesn't mean I don't need some schooling on the subject though.

Puumies · 10-30-2008, 01:40 PM

Ok. My mistake. I didn't knew that. Up here solid BB stock is one of the most used type of wood.

red · 10-30-2008, 03:51 PM

Sounds like he is talking Baltic birch plywood. I used this for all my drawers and dovetailed them with a Leigh jig and Leigh dovetail bit with great success. The first pass was slow to cut a relief across the piece then in and out of the dovetail slots. Maybe your bit is dull. I would try a new Leigh bit and see if the results are better. Otherwise, using another board to sandwich it in will work but you are cutting way more material. Good luck. I’m glad you are doing dovetail drawers. It’s a sign of quality and they’re easy to do.

Red

mmwood_1 · 11-01-2008, 08:13 AM

Quote:

Originally Posted by 338reddog

I need some advice
I am making some drawers using baltic birch and my jet dovetail jig when I make the first pass across the face the wood splinters.Some of the slinters as long as an inch. What am I doing wrong? Is this the nature of baltic birch.

I'm not familiar with the Jet jig, but if it's like most, then what you need to do is run your first pass backwards, from right to left, in the direction of the bit's rotation. Just deep enough to penetrate the first layer of the ply so that it will be scored, then go through and route your dovetails. The bit will want to grab into the wood and run away from you if you go too deep, so be careful. I make a lot of drawers with BB and I always dovetail them. Rarely have any splitting out with this method.

mics_54 · 11-01-2008, 09:27 PM

After thinking about it I have to suggest as mmwood1 stated.. you must make your first pass from right to left on the face of the side panel allowing the bit to "run" a little thereby cutting into the wood on the leading side of the bit. Also whe doing the parts on the left side of the jig go extra slow when making the final stab on the last pin so as not to rip out the edge of the top piece.

338reddog · 11-03-2008, 04:38 PM

I am using the BB ply, I am also using a frued dovetail bit. I have been making a shallow cut across the face before I start cutting dovetails from right to left. I still get the splintering and half of the pin (dovetail) comes off. The splintering is not just limited to the dovetails as the edges of the drawers splinter as I sand them. I am considering going to poplar.

dbhost · 11-03-2008, 05:08 PM

I am having a similar problem with white pine. Folks have been telling me to try using a sacrificial piece over the actual piece being dovetailed to eliminate tear out. Wood magazine had some articles on doing that as well..

mmwood_1 · 11-04-2008, 04:36 PM

Weird. I just dovetailed 13 drawers this morning, using BB and had 4 tear-outs, where I didn't do the scoring pass deeply enough. My tear-outs were about 1/8" wide and maybe an inch long. Glued them back in, no problem.

So I have another suggestion. Is your reverse pass deep enough? On my Omnijig, if I set it up so that when I assemble the drawers, the joints are flush, then I cannot make the first pass deeply enough to avoid the tear-out, because the termplate is too far to the front edge of the wood. I have to set it up so that when I assemble my drawer tightly, the sides will push in more than the width of the front and back, by either 1/32" or 1/16". I have to take that into account when I calculate the finished drawer sizes, and I have to pass the drawers through the trim bit on the router table after glue-ups. But it virtually eliminates tear-out. As I had stated in my previous post, ideally, you want to cut through the first layer of ply on your initial pass.

338reddog · 11-04-2008, 07:30 PM

Mark
Let me first say the work on your link is very nice.
I am not sure if I follow your suggestion.
Are you saying that by setting the base plate guide deeper I should not have as many tear-outs? Some of my pins are almost splitting in half, if I deepen the cut wouldnt that increase the tear-out? I am also having the top edges of the drawers splinter when I am sanding, I am afraid that someone will catch a splinter. Thank you for your advice.

mmwood_1 · 11-05-2008, 10:20 AM

reddog,

If you adjust the finger template of your jig a little further back, so that the bit can cut into the face of the ply enough to score through the first layer of ply, then when you make your full cuts going left to right, the bit's rotation won't be able to pull out that face layer of ply. So, yes, you should be able to minimize, if not eliminate tear-out on the ply face.

However, you may still have a small portion of the pins tear off (this is the nature of dovetailing BB plywood). It is the part which will not be seen because it's the back edge, which gets pressed into the joint. If your joints are snug and you apply adequate glue, this will not adversely affect the strength of your joints. If too much is tearing off (like half of the pin) then slow down a bit when you're rounding those curves on the template.

As for the top edges, I run them through the jointer before I rip the parts to size, then after machining is done, I set up the router table with a 1/16" radius round over bit and I run the top and bottom edges through. I get a very clean edge. After assembly, I use a palm sander to finish sand the drawers with 220 grit and I do the top edges also. Only once in a while do I get an edge which is 'splintered'. I try to give them a quick look when jointing and select the better edge for the top edge. This usually avoids a splinter section on the top edge.

johnv51 · 11-05-2008, 03:35 PM

I stopped using plywood for drawer sides for this reason. For drawers that will hold clothing I use cedar for the sides and back. For all others either fir or poplar. I resaw the sides and back to 1/2" thickness.

mmwood_1 · 11-06-2008, 06:48 PM

Quote:

Originally Posted by johnv51

I stopped using plywood for drawer sides for this reason. For drawers that will hold clothing I use cedar for the sides and back. For all others either fir or poplar. I resaw the sides and back to 1/2" thickness.

I've done that on occasion, too. But it's a lot more time than using BB ply, for obvious reasons. By the time I could re-saw and plane, not to mention jointing and edge gluing for drawers more than 5" in height, they get to be very expensive drawers. There was a time when I could readily purchase 1/2" stock of alder or poplar from the hardwood dealers, but no more. I'd have to take it out of 13/16" stock. So I only do that if it's important to the customer to have solid wood drawers, and they're willing to pay significantly more for them.

johnv51 · 11-07-2008, 05:53 PM

When you include the time used making the sides 2 or 3 times over because of chip out it doesn't take as long as you would think.

I can resaw on the table saw fairly quickly (at least quicker than it takes to set up and use the bandsaw) and the thickness planer will usually get it to the correct thickness in a couple of passes.

As for customers, I don't even offer BB to them. But then I don't normally build kitchen/bathroom cabinets either. Just furniture. If I started taking on kitchen or bath commisions I might have to reconsider.

GeorgeC · 11-08-2008, 06:39 AM

I also do not like plywood drawer sides. I have used manmade "wood" but really prefer solid wood.

I do not know what your price range is for drawer wood, but Lowes carries thin (1/2" and 1/4") craft woods. The local store has these in both clear pine and popular. I usually do not use a lot of drawers so the cost is not prohibitive.

George

mmwood_1 · 11-11-2008, 09:59 AM

[quote=johnv51;49689]When you include the time used making the sides 2 or 3 times over because of chip out it doesn't take as long as you would think.

The whole point of my post was that I eliminate almost all chip out with this method. For the 14 drawers I just made (that's 56 sides) I had 4 thin chip outs, which I just glued back in. No more than 5 minutes all told to repair them.

For my customers, it's well worth it to them. At a rate of $35/hour, for kitchen, bathroom, or utility cabinets, it really doesn't need to be solid wood. And I also make a lot of deep drawers for people. We're talking about 8"-12" height. I cannot hardly get solid wood in those widths, let alone re-saw it. So it would mean glueing up 2 or 3 narrow boards, then planing. I only do this for furniture, or by specific request of a customer.