I have several shelves that I cut for a cabinet that need to be made square. I build a small handheld perpendicular sanding block to sand the edges of the plywood square. This plywood is 3/4″ birch and it seems like it takes a longgg time sanding with rough sandpaper to square an edge. Does anyone have a better method to square plywood edges?
thanks,
Dimitri
Replies
What equipment do you have in your tool inventory for cutting -- table saw, circular saw, SCMS, etc?
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"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
I used a circular saw with a straight edge for every cut. However, several of the edges still need to be made square.
Dimitri,"I used a circular saw with a straight edge for every cut. However, several of the edges still need to be made square." It has already been mentioned that you need a good square to check the blade alignment with the base of the circular saw. You cannot rely on the degree markings (or angle stops) to be accurate. In addition, you need a good quality circular saw that does not allow flex between the base and motor/arbor, and with good bearings so that there is no blade "wobble." I'm not familiar with any of the current models (I bought my circular say many years ago) but I handled every model I could find in all the local shops until I found one that seemed to have the best overall quality and little (if any) flex in the motor-to-base connection. (The saw model I bought has been discontinued since then.) Even with this, I am still very careful to set up my cuts and my stance so that I can provide even pressure on the saw grips during the complete length of the cut.If you cannot get adequate cuts with a circular saw, and you don't have a table saw, the suggestion to use a router for the final "cut" may be the best solution.Good luck,
Richard Baker
Did you square up, and then clamp the straight edge you used?Unless the the clamps didn't hold, and the straight edge moved, that should give you a square cut.********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Edited 9/7/2005 9:08 pm ET by nikkiwood
I did notice that when I was cutting the plywood with the circular saw that sometimes the back of the saw would slightly move away from the clamped fence. Perhaps I should slow the cutting process down even more? What could cause that and how can I prevent it from happening?
Dimitri
I've had that happen to me and it's usually when I'm making long cuts. I seem to shift my grip slightly when I step forward and that kicks the heel of the saw away from the guide. It can also happen if you're too focused on keeping the front of the saw tight to the guide and let the heel wander.
For me, it's just a matter of making sure I keep my movement as smooth as possible. For really critical cuts, I make my circular saw cuts slightly oversized then finish with the table saw.
Thanks Dave! It makes sense what you are saying. I'm thinking of using my router with a flush trim bit and square up those edges! What is your opinion?
I think would experiment with some scrap first. That veneer is mighty thin and it may splinter pretty badly. I think a better solution to get square edges is to make sure your saw blade is square to the plate and that the blade doesn't "wobble" or flex whle you're cutting.
Two other things that have caused issues for me when cutting with circ saw against a straight edge are:
Dull blade - especially high tooth count plywood blades seem to dull easily. They never seem to dull evenly, so end up pulling & wavering.
Cutting too thin of a strip - it's hard to keep a circ saw level if it doesn't have a lot of wood to rest the base on.
I had a horrible time recently crosscutting 3/4" maple plywood with a new! carbide! plywood blade and my circ saw. Kept pulling to one side and splintering like crazy. I ended up going with my Bosch jig saw with the anti-splinter insert and a T101B fine cut blade. No chipping either side and an exceptionally straight clean cut. Less "drama" than the circ saw as well, and much easier to clean up afterwards.
If you are going to be doing a lot of this type of cutting I'd suggest looking into a guide system. One that is getting a lot of interest (and satisfied users) on the Breaktime forum is the EZ Smart Guide from Eurekazone. Google them - they have a number of models.
This type of plywood cutting is something I do rarely. I found from experimenting that the blade that worked the best for me with the 3/4" birch plywood is a 40 tooth carbide tipped blade from Black and Decker. I tried a plywood blade with all those teeth and a 20tooth and a 60 tooth. These gave me unpredictable cuts ranging from burnt edges to lots of splintering. The 40 tooth worked the best for me.
I will do the following based on these posts that are always helpful:
1. I will take the 40 tooth blade out and clean it with a solution I purchased from Rockler to clean bades with.
2. When I cut the plywood next time, I will proceed at a slow and consistent rate with the circular saw. I am finding that this is the best way for me to minimize if not eliminate uneven cuts. I think that what was happening is if i tried to rush the cut a bit.
Dimitri
I think practice is the answer here. Do you know about "shooting boards"?********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Hiya,
Its interesting you mentioned shooting boards. I have been looking at a simple design to build one. I just purchased a LV low angle smoothing plane to use with the shooting board.
This weekend I used my router to trim those edges on the plywood. Its worked out very nice!
Do you have any of the Lee Valley planes?
Dimitri
Re: shooting boardsI have a set that I always use when cutting sheet goods with my circular saw. Planes?I'm one of those who never does by hand what I can do with a machine. I do own ####Lie-Nielsen block plane, though -- and a couple old Baileys.********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Get one of those combination upcut-downcut router bits and a good straightedge and square and straighten them at the same time with a router.
The Professional Termite
Hi dimitri; I don't know if you used a circ. saw to cut your shelves. But I have noticed a lot of people run very thin kerf blades in there circ. saws for more power. In my opinion a good quality full kerf blade, will cut better than a cheap thin kerf, and will have very little deflection. So with a good full kerf blade, a square to set the blade to the base, and a good straight guide fence clamped in place, you should make nice square cuts.
Cheers. Walker1
A couple of ideas:
1. When using a straightedge and circular saw, you will get better results with a blade that is set "toe out" which means that the rear of the blade is a little bit farther from the cut line (and into the waste) than the front of the blade. This will avoid the "snipe" at the end of the cut when only the rear of the blade is engaged. So how much toe-out to use? Try about 0.02" (or 1/64-th) to start.
2. An edge plane can be used to square off an edge. It's a lot quicker than setting up a router/straight-edge, and it takes such a thin shaving that you usually don't have to consider the miniscule reduction in workpiece width. Lie-Neilsen and Veritas (Lee Valley) both make excellent edge planes with very low blade angles that work well on plywood.
Nick,
What do you mean by an edge plane? Lee valley sells beautiful planes. Do you mean a low angle smoothing plane or even a low angle jack plane?
Dimitri
An edge trimming plane has an integral fence perpendicular to the sole, so that when you plane an edge the fence bears against the face of the workpiece. The result is an edge that is perpendicular to the face. The original edge trimmer was the Stanley #95, long since discontinued. Lie-Neilsen makes a version of similar size, and Lee Valley make one that is bigger. The Lee Valley catalog number is 05P02.05. It may see odd to plane plywood edges, but I do it all the time. The low-angle planes work best, including the edge trimmer.
Nick,
I have seen that small edge plane that you mention in Lee Valley's catalog. I remember reading about the 95 plane. Can my low angle smoothing plane that I just purchased from Lee Valley work on plywood edges too?
Dimitri
How well does that plane edge last?I use a block plane with a guide I made for it. (Yep.. screded into the bottom.. Cuts well 'for awhile' Plywood a killer on the blade...EDIT:: screded? Well, I was close...
Edited 9/17/2005 10:59 am ET by WillGeorge
good pattern router bit and a straight edge (like a six inch wide board)
Here's a great technique: https://www.wwgoa.com/video/squaring-plywood-with-a-router-woodworking-video-004641/
An accurate guide and a slow steady feed rate.
Check to see if your blade is parallel to the edges of the plate because that can cause issue with tracking.
If you have an engineering square or a roof rafter square and a No 4 or 5 hand plane with a sharp blade it's not that hard to do it by hand. You can use the square to see where the high points are and then remove some material. Check frequently. That's what I've done when working with plywood and I needed the corner 90 degrees. Obviously a shooting plane would help as well. Really depends on what you own.
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