Shopsmith Forums

I got a piece of Maple furniture grade plywood at Lowes and it is giving me fits. Rip or Crosscuts using a plywood blade no problem. If you try anything else it just splinters like mad. This is not just a Shopsmith question but I get good answers here. I am using a router table for this but I could just as easily use the Shopsmith. I am trying to crosscut a 1/4" slot using a new bit in this plywood and it looks like I was using a dull ax to cut it. I tried scoring the veneer with a utility knife and I tried taping the cut area with painters tape but no joy. I have already ruined two pieces so now I am using them for test cuts before I try again with a good piece. The rabbets worked OK but the slots are killing me. Any suggestions?

Michael

For me, routers and plywood don't work together. I try to design my builds so the router never gets to cut into plywood anywhere. Routing solid wood works well if the bits are sharp and I make small passes.
If I have to cut grooves into plywood, I do it with a dado blade instead of using the router.

It all boils down to how much you are willing to spend but one way you can avoid that splintering is buy plywood that is made used a hardwood core. Less expensive plywoods (ie lower quality plywood) does not. The interior core material is typically fir.

If you chose to go the quality route be prepared to pay upwards of $50 and up for a 4x8 sheet of 3/4 birch plywood.

Had to search but I found this: http://www.popularwoodworking.com/techn ... ht_plywood

If you intend to build with plywood, this is worthwhile reading.

I've never tried one on plywood, but I'm wondering if a spiral downcut bit would help you. That would have the inner plies backing up the veneer cut. I have a Whiteside carbide downcut that I use on hardwood, and it does a nice job of eliminating the fuzzies on the edge of the cut.

I'd too would use a down cut spiral bit. Small cuts. While painters tape didn't help, and I wasn't surprised, you can add a sacrificial piece of hardboard to the stock and cut through both. Finally, it wasn't clear to me if you are cutting from the edge of a board or plunging in the middle. But if plunging I'd forget using the table and just use a plunge base on the router. Just my 2¢.

Try using blue tape. Put the tape across the cut line and router your groove down the middle of the tape. It will eliminate a large portion of the tearout.
Paul

Tear out is a PITB,,,

Sharp bits will help a lot.
Score the board deeper with your knife before cutting.

There are no guarantees you are cutting glue and pressed wood chips ,



Just my .02
Good luck

Along with Dennis and berry, I believe your best bet is a down cut spiral bit. You said you could use a router table. Instead, i believe it would be better using the router hand held and use a straight edge guide. Then you can see your cut and tailor the router rpm and your feed rate to get the best results.

Just a thought.

Be well,
Ben

dynabase wrote:I got a piece of Maple furniture grade plywood at Lowes and it is giving me fits. Rip or Crosscuts using a plywood blade no problem. If you try anything else it just splinters like mad. This is not just a Shopsmith question but I get good answers here. I am using a router table for this but I could just as easily use the Shopsmith. I am trying to crosscut a 1/4" slot using a new bit in this plywood and it looks like I was using a dull ax to cut it. I tried scoring the veneer with a utility knife and I tried taping the cut area with painters tape but no joy. I have already ruined two pieces so now I am using them for test cuts before I try again with a good piece. The rabbets worked OK but the slots are killing me. Any suggestions?

Michael

Having read all the posts to this point I agree with them. However, a few things come to mind. IMO Lowes (or any big box store) does not sell "Furniture" grade plywood. Not all plywood is the same. Until you see the difference it is hard to know. Yes, you will pay more for really good quality plywood. More than Lowes.

Not all router bits are created equal. The best router bits IMO are Whitside (made in the USA by a family owned business in North Carolina). Yes they are a bit more expensive but worth the extra price for critical operations.

I learned my lesson on Lowes or Home depot plywood but I am stuck with what I have. I will not do that again.

I am using a Whiteside bit from their cabinet builder set. I need several grooves in this project. I need 1/4 and 1/8 grooves. I am using the white side bit for the 1/4" groove and I will decide what to use for the 1/8 later. These are the first cuts I have tryed with the Whiteside. I took it out of the wax to use on this project.

I haven't tried it yet but I am going to experiment with feed rate and router RPM speed tomorrow to see if I can resolve some of the veneer chipping. I think the router is currently set at 20K RPM and it probably should be around 15K RPM with this slot cutter bit based on what I've read lately.

Thanks for all the replies.

Michael