I am building a large veneered cabinet. The corners are mitered so grain flows from top to sides. Top is 17” d x 58”w x 1.25” thick. Sides 29” long
I cut the miters with a friends Festool track saw. When dry assembling, each joint was found to vary from 45 deg to 45.5 deg across joint leaving a several thousands gap in the joints.
How should I correct this error w/o changing size of cabinet?
Replies
The solution to your problem is a mitered shooting board. It's been my experience that you will never achieve perfect miters on cuts like that, and I'm impressed the track saw did as well as it did. To clean up the miter now you need to shoot it, but since it's not practical to lift such large pieces at a 45° while the plane runs parallel to the bench you need to build a shooting board that lets the piece sit flat and tilt the plane 45°. Something like this is what I use.
https://www.finewoodworking.com/2020/09/02/essential-hand-tool-jigs-for-woodworkers
Obviously you will need to scale it to fit your project, but it will let you dial in the miters will removing a minimal amount of stock.
. I was thinking a shooting board would be the solution. But pieces are large as you say. I appreciate your response.
I added a link to a board Tha properly sized will do the job. It doesn't need to be full length as long as you put a support the same thickness under the board to insure it is truly flat. If it was me I would build the base about 6 " longer than needed, maybe 30" then just cut off the 6" piece to use as a support for the longer top, knowing it will be the exact same thickness. Also put some thought into how you will clamp it. You may want to put runners underneath to raise it off the bench to allow clamp heads to fit under it.
Shooting with a plane is choice #1. If you are not adept with hand tools a router with a 45* chamfer bit mounted to a square base and running along a guide rail could do the trick. The square base will prevent rotation in case the router is not concentric.
That is a large piece and shooting it may be difficult.
William Ng has a video that may give you some ideas about other techniques to close up the joint that don’t involve shooting. If the gap is small some of his suggestions may be helpful.
https://www.youtube.com/watch?v=gyHtW_x8Y64
I’d be hesitant to use that technique on veneer that’s ~ 10 thousandth thick. Plus the miters need to provide as much surface as possible for joint strength. But interesting solid wood technique.
That's an old finish carpenter trick used to close up outside corners on crown and baseboard. I would be a bit hesitant to use it if I were planning on staining the piece unless I was using hide glue.
If you're only talking about thousandths, is a sanding block out of the question?
I’ve set up a shooting board like esch5995 suggested and am starting with a sanding block. Seems to be working.
This is very tricky!
If the angle is too short you're ok, but if you take material off the long side, you're changing the dimensions and throwing off all the other corners.
The Ng video is well worth watching.
BTW it helps to give yourself a name so we can see when you repost.
I’m not sure I understand “ angle is too short”. Do you mean like less than 45 deg? And “ long side”. Not sure what that means.
Could you post a pic of the dry assembly & the gapping ?
I've been thinking that the parts are plywood and already veneered...is this the case? If they have not been veneered yet the open corners could be addressed and squared before the veneer goes down and your grain lines would be perfect.
Already veneered
I’ve created a screen name as requested. Sorry for inconvenience to anyone. I’ll add some pictures showing what I’ve set up to try and correct these joints. One of the cabinet sides in jig.
That is a nice jig. But tell me, how were you able to cut those nice miters on the jig but not on the cabinet sides ?
Jig pieces are much smaller and we’re easy to accurately register on table saw. I bit off too big a project thinking a German track saw would give me dead nuts accuracy. But the track/ saw interface must have a little play. Be zero problem on 3/4” sheet goods but my glue up is 1.25” thick. I’m thinking I can correct the sides by making a big table saw sled. But the top and bottom, I’m gonna use the jig (referenced in someone’s early post )and the sanding blocks (also suggested) and sneak up on an accurate joint. Next time I waterfall an edge it’ll be a way smaller case. You can count on that😎
I wanted to thank those who provided tips here. I built the jig suggested. While I’m comfortable with my planes, I found it far easier to sand the miters to get a very good exterior fit. I went from .025 gaps and an out of square case to gaps That are .006” or less. The case is dead square on the numbers. Miters are slightly gapped inside but those will be covered with corner blocks. I will assemble with West System Six10 which is gap filling epoxy.
By the way, I’d never felt I needed band clamps. These Pony brand clamps really much easier to use than bar and pipe clamps in this application. Again, thanks.
When I miter panels I opt for a lock miter joint, best performed on a spindle shaper with a power feed, I find the joint to be extremely accurate, self squaring, and easy to clamp. I have been using this method regularly attaching finished end panels to face frames.
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