So I decided to try some kumiko panels.
Made the blocks, check for accurate angles – check.
Mill up some basswood to 1/2″ – check.
Rip some 1/8″ strips – check.
Sled with a sacrificial piece with notch – check.
Use sled to notch out on the strips – check.
Assemble to a nice 4 square pattern – check.
Measure out the pieces, slightly oversized – check.
Place said piece in 45 deg block – check.
Adjust stop on block to create 45 deg bevel – check
Use sharp chisel to slice one end – check.
Rotate piece to create the 45 deg, point meets in the middle – check.
Flip end for end to do other end……..
At this stage, the stop is securely fastened, the other end appears “short”. I can’t seem to create the same nice 45 deg that meets in the middle. At first I thought that the chisel was dull thereby pulling the stock ever so slightly out, so I re-honed it to 16k used the “hold fast” to hold the stock in place in the block. But still it ends up a hair short.
Any thoughts on what I am doing wrong?
Replies
From your description I'm guessing that you're dealing with an accumulated error with that last part. A slight error repeated throughout a pattern will show up at the end. That final inside corner might not be 45. Use a short piece to sneak up on a fit so you can measure the angle that's there before making that last part.
That's what I was thinking as well, accumulated error.
I was thinking accumulated error too.
I'll give it a try.
It is a good idea to make the pieces on the tight side as basswood will compress a bit and conform to the angle if the cut is not far out. While this method is not the solution to gross errors it will over come a slight variation.
Cheers
I've had the same problem and I wish I knew what "fixed" it but it just seemed to go away as I made more pieces. I know if I don't focus on each step, allowing some "slop" into the mix, problems show up.
Do the strips fit snugly in the groove in the block? Is there wiggle room so that the piece is shifting when you make the chisel cut?
Are the ends of the pieces "clean" (before you make the 45 cuts) or is there a rough splintery look to them?
The pieces fit very snuggly, in fact I had to gently file a little to there is no lateral movement. When measuring with a small machinist square the bevel edge on the piece is 90 degrees.
I've completed the Asa-no-ha now, but I had to more or less tweak every individual piece. Its just weird, I must be doing something wrong. I set the stop on the block after sizing a piece that fits, then (given that the squares are square) its just rinse and repeat.
But like you said, this is my first go at Kumiko will sure get better over time.
That looks really really good. Another thought is to make certain that your outside structure is perfectly square. If it is not square that can make a big difference in how the small pieces come together. One thing I did which seemed to help. I cut all the grooves in larger blocks using a pin system like you would doing box joints. That helped getting things consistent and square. After cutting the grooves in the master block I then cut the strips and used a plane and thickness jig for the final dimension.
Excellent work Marius!
Well, what you describe is totally what should be expected: every piece is fit individually, there's no way around it.
I usually use a piece of a business card in as a shim when cutting the second end, do this every time and the results will be consistent, also helps to get a nice light last pass on some more extreme angles like 15 degree ends that tend to pull out of square slightly.
Also if you mill your stock to half inch but leave your boards wide (say 3”) then notch, then rip into 1/8” strips you will spend a lot less time notching and not have blowout on the exit side of your notches, this greatly speeds up the process….until you try triangle grids, then it’s a one at a time kind of operation
The nice part about basswood is that it compresses, so a slightly oversized "locking" 45d piece can be judiciously fitted into the Asa-No-Ha pattern. When I teach Kumiko to students, I have them make the 45d ends ever so slightly longer and then trim back to fit. Better a tight fit to lock everything together. Also make sure the 45d bevel is parallel to the end. If the strips haven't been milled coplanar you can get a skewed, mitered bevel at the end . This will affect fit. Yeah, improved fit comes with doing more of it as others have said.
Norman
It all starts with the frame. I devised an indexing template for my table saw fence that ensures a perfect dimensions.
If you're interested you can PM me over on Woodworkingtalk @DrRobert.
One thought I had was that you might be taking too heavy of a cut on your 1st 45 degree cut which will tend to pull the piece away from the stop and would create your error. Depending on how much I have to remove I will take several lighter passes by keeping the chisel off of the reference block until the final pass. Usually once you do the 1st 45 degree cut the second one will not have much material left so you can do it in one pass.
I've done a far bit of Kumiko and here are a couple of suggestions for you.
Try using an extremely sharp block plane instead of a chisel as chisels do tend to pull the piece out of alignment on the block.
Check the face angle of your block quite often.
If you need 30 pieces, rough cut 45 and take the best. Unless you are a master, Kumiko wastes wood.
Do each 45 individually. Some blocks will take 3 pieces at a time but any error is multiplied.
There is an Australian named Des King who has some excellent videos. Check out Taeho's Kumiko club (Wood Art Studio)also on YouTube.
Here's a photo of the shutters in my shop that I did to learn Kumiko.