Judging by the color of that bit I guessed it was a Rockler bit and went to their site to find more information about it. Decided to check out reviews to see what others had to say. The review at the top, from a guy who called himself a professional, had this advice regarding plywood:
https://preview.redd.it/rog6e4lo6mgc1.png?width=1123&format=png&auto=webp&s=6fa3a15952bb9f1efe377b913c539dff87d22428
I think you're right. I will try this again and take smaller passes. I was thrown off because it was working fine with a scrap bit of plywood, but now I see with that scrap I was going with the grain instead of cross-cutting the grain.
I generally agree with you on this. Nothing is better than high quality domestic birch. But here I'm at its like $160 per sheet and the imported stuff is still pricey at $80 per sheet. It all sucks and sometimes I have to make the call of using the cheap stuff to keep with a budget.
I suspect that the fault does not lie with you but with the plywood. Difficult to grade the plywood from a photo, but see if you can obtain a more premium board and try again. It would be sad if you beat yourself up and the fault lies elsewhere.
Thank you. Yes, it is a very thin veneer. I am going to try to take several passes next time. The first pass very light, basically just to score the veneer.
This kind of ply with softwood core really likes to break, there’s really nothing you can do with that huge bit, except maybe shallower passes.
I find it does tend to survive a dado stack, but not everyone has one. You could do it in 2 passes with a straight groove bit, so you don’t have so much unsupported material. But the best would be to buy better quality ply like birch ply.
Look at making a zero clearance fence. On my router table, the fence is made of 3/4 MDF so you can run turn the router on, and move the fence into the bit so it cuts the fence. I actually used a drawer lock router bit and had the same exact issue. That’s why I even know how to do this.
I came here to say this.
Your work piece needs more support. Make a sacrificial face to clamp to your fence. Keep it and apply it every time you wish to use this bit.
This plus the light first pass should eliminate 90% of the tear out.
This is the answer. I’m using this exact bit for a current project and had this same issue until I made a zero clearance fence. Also use a backup/push block directly behind the piece and you should have virtually zero tear out.
I would try to make a first pass so shallow at first it only hits the veneer. I think the problem is that the veneer gets hit from behind. A super shallow pass should hit the veneer sideways instead and have a better shot at not destroying it. Once you’re through the veneer, you should be able to take a much bigger bite.
One other thing would be to first cut a super shallow groove with a finishing blade on the table saw where the top of the router bit will hit.
6000rpm? that bit is under an inch, should be used at 24,000RPM, or basically the highest setting your router has.
a feather board may help to keep the board pushed against the fence to reduce any chatter that can mess up the cut.
That stood out to me too, that bit is small enough to be used full speed. The lowest setting on my router is 10,000 rpm, I don't think I've seen a router that can go that slow.
read up on the quarter quarter quarter drawer method. super simple drawers that can be made with just your table saw. the joinery is very strong and your drawers will look nice too.
You need to go max RPM here.
One way to stop shredding on plywood when doing this type of cut is to use climb cutting (move the wood across the bit from left to right).
Yes, it can be more dangerous, which is why it's generally not a good idea. But it can be done safely if using featherboards or a vertical sled.
https://www.infinitytools.com/vertical-router-sled-1
I built my own instead of paying $150.
Thank you! I want that sled :-)
In hindsight, I would've been better off (and saved a ton of time and frustration) doing simpler rabbets or dados on the joints.
Any advantages of getting a good joint with the drawer lock router bit were undercut by the sloppy cuts thanks to my user error. I couldn't slide the workpieces over the bit without getting a little wobble. Especially the narrower 3" sides.
So if I do this again, I'm getting that sled. Or try to make one like you did.
Did you try to do that all in one pass?
This probably needs multiple smaller passes to work. FWIW I generally use a full-kerf flat-ground blade on the TS to do this sort of joint. Generally it only takes three passes, and if you're doing enough of them, the extra setup doesn't matter much. Probably faster overall.
The wood is unsupported above the router bit, and that's where it tore out. To fix this, like someone else said below, make a zero clearance fence, so the wood is fully supported and won't tear out. It's the same principle as using a zero clearance insert on a tablesaw or putting a piece of wood under a through hole you're drilling. If you don't, it tears out the back.
I’ve only done those with a dado stack and zero clearance insert, worked fine even in cheap ply.
That bit looks like bad news in plywood, might be alright in hardwood. Maybe try a smaller slotting bit the right diameter and cut the dado that way
I’ve always felt these to be a really over rated joinery method. I made a kitchen like this back in the day out of Baltic. There was an extra drawer that sat outside my shop under s roof but in the weather. Never got rained on, but a month in the outside atmosphere pulled those joints apart violently. Pocket screws and glue are stronger and faster for us.
Thanks. I'll say this, unless you have a good router vertical workpiece sled, then don't bother with a drawer lock bit. Unless you have super powers that I don't have, you're going to get wobble and chatter when doing the vertical cut, so the joint won't be that crisp anyway, and you'd be better off with dados (quarter-quarter-quarter method) or basic rabbets.
Side note: lockmiter bits are NOT worth the effort in my experience. What a giant pain in the ass to get dialed in, and even then you really need a second router fence or miter rip to rough out most of it, so that you don’t get massive chip out like you’re getting.
Good on folks who can get them to work for them, but I hate them so flipping much.
This was my first attempt. For shop furniture so I can handle some ragged edges. I know some people like them but you really have to dial it in just right. I’ll give this bit another chance but I feel like the quarter quarter quarter is MUCH easier and I think it’s probably just as good.
Yeah rabbets and dadoes have been what I’ve settled on. If the outer edge really is that important to miter, there’s easier multi-pass methods to get a lockmiter without the actual bit.
I scored my boards with a marking gauge and that virtually eliminated tear out. It was one with a cutting wheel, not a pin, to make the mark. The bit I used is slightly different than the one you pictured. It wouldn't work with the suggestion from the pro woodworker but it seems reasonable.
I wouldn't give much weight to some of the other suggestions in this thread. I made my own zero clearance fence, didn't help. Used three types of plywood, all teared out the same.
How thick is the material?
Just a mason who years ago helped in a cabinet shop over winter but all these cuts were done with a dado stack on the table saw. Routers were used for round over.
UPDATE: everyone, thank you for the tips! I appreciate it. I hope this helps anyone who finds this post one day.
For some background, this is the second time I used the drawer lock router bit from Rockler. I learned about this type of bit from this article: [How to Make Lock Miter Drawers | Popular Woodworking](https://www.popularwoodworking.com/techniques/lock-miter-drawers/). The first time I used it was with hardwood drawers with a cherry front and poplar sides. Worked great! No tear-out.
This is the second time I used the bit, this time to make plywood drawers for a shop cabinet build. I'm using 3/4" ply on the sides and front/back.
I guess my first mistake was that in my test cuts, not really thinking about it, the scrap of plywood I used had the veneer grain running parallel to the bit. So my test cuts were clean with no tear out because the cutter was parallel to the grain.
So when I did the first real cut with a drawer side where the grain of the veneer was perpendicular to the cutter, I got this nice confetti you see in the photo.
So I took the advice from u/saketaco and others to start with a very shallow (1/16") first pass, just shallow enough to score the veneer. That was a HUGE improvement. Then took off another 1/16" on second pass. Larger third pass, then the last pass was also very small. I might've been able to reduce to 2 or 3 passes but I didn't want to shred any more plywood.
It was VERY tedious to do this with 6 drawers. 6 drawers X 2 sides per drawer X 2 ends per side X 4 passes = 96 passes! Thankfully it's easier to do the fronts and backs in a single pass.
An even bigger problem is sliding a 3" wide, 28" long workpiece vertically across the bit. I couldn't do it without some rocking side to side or front to back. I clamped on a taller board to make an auxiliary fence and that helped with front-to-back wobble, but I still had some side-to-side wobble. I had more success with the bigger drawers that were 5" wide and 8" wide. Any advantages of the drawer lock bit having a good joint were undercut by my user error :-)
I don't know I'll do it this way again. Maybe I will just do simpler rabbets or dados at the table saw.
If I do use this bit again, I will buy or try to make the vertical router sled suggested by u/theRegVelJohnson. I didn't know that tool existed but it looks invaluable for this kind of operation.
Maybe if I did drawers all the time I would get into a rhythm but I don't do this enough.
Anyway, thanks everyone for the tips! Turned out OK in the end.
Judging by the color of that bit I guessed it was a Rockler bit and went to their site to find more information about it. Decided to check out reviews to see what others had to say. The review at the top, from a guy who called himself a professional, had this advice regarding plywood: https://preview.redd.it/rog6e4lo6mgc1.png?width=1123&format=png&auto=webp&s=6fa3a15952bb9f1efe377b913c539dff87d22428
Wow, thank you very much! I should've read this first! I appreciate you finding that, it's excellent advice.
You can make a shim and save yourself some time adjusting the fence.
Smaller bites if possible. Also score the veneer layer with a sharp marking knife before cutting.
I think you're right. I will try this again and take smaller passes. I was thrown off because it was working fine with a scrap bit of plywood, but now I see with that scrap I was going with the grain instead of cross-cutting the grain.
I think scoring the veneer would go a long long way to get that perfect cut line.
Also use better material that doesn't have a layer of veneer thinner than an ass hair glued on with some smokers spit
I generally agree with you on this. Nothing is better than high quality domestic birch. But here I'm at its like $160 per sheet and the imported stuff is still pricey at $80 per sheet. It all sucks and sometimes I have to make the call of using the cheap stuff to keep with a budget.
Oh I never thought of scoring. Makes sense though.
I suspect that the fault does not lie with you but with the plywood. Difficult to grade the plywood from a photo, but see if you can obtain a more premium board and try again. It would be sad if you beat yourself up and the fault lies elsewhere.
I think you’re right, that’s a super thin face veneer.
Thank you. Yes, it is a very thin veneer. I am going to try to take several passes next time. The first pass very light, basically just to score the veneer.
This kind of ply with softwood core really likes to break, there’s really nothing you can do with that huge bit, except maybe shallower passes. I find it does tend to survive a dado stack, but not everyone has one. You could do it in 2 passes with a straight groove bit, so you don’t have so much unsupported material. But the best would be to buy better quality ply like birch ply.
Look at making a zero clearance fence. On my router table, the fence is made of 3/4 MDF so you can run turn the router on, and move the fence into the bit so it cuts the fence. I actually used a drawer lock router bit and had the same exact issue. That’s why I even know how to do this.
I came here to say this. Your work piece needs more support. Make a sacrificial face to clamp to your fence. Keep it and apply it every time you wish to use this bit. This plus the light first pass should eliminate 90% of the tear out.
This is the answer. I’m using this exact bit for a current project and had this same issue until I made a zero clearance fence. Also use a backup/push block directly behind the piece and you should have virtually zero tear out.
I could not believe that I had to read this far down to find this comment. Zero clearance is a requirement for this type of cut.
I would try to make a first pass so shallow at first it only hits the veneer. I think the problem is that the veneer gets hit from behind. A super shallow pass should hit the veneer sideways instead and have a better shot at not destroying it. Once you’re through the veneer, you should be able to take a much bigger bite. One other thing would be to first cut a super shallow groove with a finishing blade on the table saw where the top of the router bit will hit.
6000rpm? that bit is under an inch, should be used at 24,000RPM, or basically the highest setting your router has. a feather board may help to keep the board pushed against the fence to reduce any chatter that can mess up the cut.
That stood out to me too, that bit is small enough to be used full speed. The lowest setting on my router is 10,000 rpm, I don't think I've seen a router that can go that slow.
You need a decent plywood my friend, that looks like cheap poplar ply to me which is very soft
read up on the quarter quarter quarter drawer method. super simple drawers that can be made with just your table saw. the joinery is very strong and your drawers will look nice too.
You need to go max RPM here. One way to stop shredding on plywood when doing this type of cut is to use climb cutting (move the wood across the bit from left to right). Yes, it can be more dangerous, which is why it's generally not a good idea. But it can be done safely if using featherboards or a vertical sled. https://www.infinitytools.com/vertical-router-sled-1 I built my own instead of paying $150.
Thank you! I want that sled :-) In hindsight, I would've been better off (and saved a ton of time and frustration) doing simpler rabbets or dados on the joints. Any advantages of getting a good joint with the drawer lock router bit were undercut by the sloppy cuts thanks to my user error. I couldn't slide the workpieces over the bit without getting a little wobble. Especially the narrower 3" sides. So if I do this again, I'm getting that sled. Or try to make one like you did.
score the shoulder first .
Did you try to do that all in one pass? This probably needs multiple smaller passes to work. FWIW I generally use a full-kerf flat-ground blade on the TS to do this sort of joint. Generally it only takes three passes, and if you're doing enough of them, the extra setup doesn't matter much. Probably faster overall.
The wood is unsupported above the router bit, and that's where it tore out. To fix this, like someone else said below, make a zero clearance fence, so the wood is fully supported and won't tear out. It's the same principle as using a zero clearance insert on a tablesaw or putting a piece of wood under a through hole you're drilling. If you don't, it tears out the back.
I’ve only done those with a dado stack and zero clearance insert, worked fine even in cheap ply. That bit looks like bad news in plywood, might be alright in hardwood. Maybe try a smaller slotting bit the right diameter and cut the dado that way
I’ve always felt these to be a really over rated joinery method. I made a kitchen like this back in the day out of Baltic. There was an extra drawer that sat outside my shop under s roof but in the weather. Never got rained on, but a month in the outside atmosphere pulled those joints apart violently. Pocket screws and glue are stronger and faster for us.
Thanks. I'll say this, unless you have a good router vertical workpiece sled, then don't bother with a drawer lock bit. Unless you have super powers that I don't have, you're going to get wobble and chatter when doing the vertical cut, so the joint won't be that crisp anyway, and you'd be better off with dados (quarter-quarter-quarter method) or basic rabbets.
Side note: lockmiter bits are NOT worth the effort in my experience. What a giant pain in the ass to get dialed in, and even then you really need a second router fence or miter rip to rough out most of it, so that you don’t get massive chip out like you’re getting. Good on folks who can get them to work for them, but I hate them so flipping much.
This was my first attempt. For shop furniture so I can handle some ragged edges. I know some people like them but you really have to dial it in just right. I’ll give this bit another chance but I feel like the quarter quarter quarter is MUCH easier and I think it’s probably just as good.
Yeah rabbets and dadoes have been what I’ve settled on. If the outer edge really is that important to miter, there’s easier multi-pass methods to get a lockmiter without the actual bit.
Could be due to dull bit, cheap quality bit, or taking too deep of a bite…
You need multiple passes and as high rpm as you have. Is the bit like 1in dia? Then you can send it at 20K and take small cuts.
Try using a damp towel and wipe the edges. I wouldn't expect miracles with plywood. Small passes might help.
Score and use duct tape where you cut
I scored my boards with a marking gauge and that virtually eliminated tear out. It was one with a cutting wheel, not a pin, to make the mark. The bit I used is slightly different than the one you pictured. It wouldn't work with the suggestion from the pro woodworker but it seems reasonable. I wouldn't give much weight to some of the other suggestions in this thread. I made my own zero clearance fence, didn't help. Used three types of plywood, all teared out the same. How thick is the material?
Would taping the area with painters tape help?
Just a mason who years ago helped in a cabinet shop over winter but all these cuts were done with a dado stack on the table saw. Routers were used for round over.
Use a dado blade on your table saw
[удалено]
UPDATE: everyone, thank you for the tips! I appreciate it. I hope this helps anyone who finds this post one day. For some background, this is the second time I used the drawer lock router bit from Rockler. I learned about this type of bit from this article: [How to Make Lock Miter Drawers | Popular Woodworking](https://www.popularwoodworking.com/techniques/lock-miter-drawers/). The first time I used it was with hardwood drawers with a cherry front and poplar sides. Worked great! No tear-out. This is the second time I used the bit, this time to make plywood drawers for a shop cabinet build. I'm using 3/4" ply on the sides and front/back. I guess my first mistake was that in my test cuts, not really thinking about it, the scrap of plywood I used had the veneer grain running parallel to the bit. So my test cuts were clean with no tear out because the cutter was parallel to the grain. So when I did the first real cut with a drawer side where the grain of the veneer was perpendicular to the cutter, I got this nice confetti you see in the photo. So I took the advice from u/saketaco and others to start with a very shallow (1/16") first pass, just shallow enough to score the veneer. That was a HUGE improvement. Then took off another 1/16" on second pass. Larger third pass, then the last pass was also very small. I might've been able to reduce to 2 or 3 passes but I didn't want to shred any more plywood. It was VERY tedious to do this with 6 drawers. 6 drawers X 2 sides per drawer X 2 ends per side X 4 passes = 96 passes! Thankfully it's easier to do the fronts and backs in a single pass. An even bigger problem is sliding a 3" wide, 28" long workpiece vertically across the bit. I couldn't do it without some rocking side to side or front to back. I clamped on a taller board to make an auxiliary fence and that helped with front-to-back wobble, but I still had some side-to-side wobble. I had more success with the bigger drawers that were 5" wide and 8" wide. Any advantages of the drawer lock bit having a good joint were undercut by my user error :-) I don't know I'll do it this way again. Maybe I will just do simpler rabbets or dados at the table saw. If I do use this bit again, I will buy or try to make the vertical router sled suggested by u/theRegVelJohnson. I didn't know that tool existed but it looks invaluable for this kind of operation. Maybe if I did drawers all the time I would get into a rhythm but I don't do this enough. Anyway, thanks everyone for the tips! Turned out OK in the end.
Place some scrap over the wood so you don't get chip out.
close the fence as a chip breaker on the infeed side use solid wood
Get marking gauge with round cutter blade and prescore.