Fine Tuning Fit

[Jonathan McCully]

This might seem like a simple question, but one I've been thinking about as I'm working on getting my barn door put together. When you're trying to sneak up on the fit of a board or need to shorten the length of a tenon, how do you go about making that crosscut? I'm talking about small increments here, like 1/32". I've tried to use my block plane, and maybe it's not sharp enough for the end grain cut, but seems to really struggle with that. So, I've reverted to making very tiny cuts on my table saw or miter saw which works, but most of the time seems like I'm just guessing. I'd ultimately prefer to be a bit more precise if possible, thus the question to you all. How do you go about fine tuning the fit?

[BonPacific]

There's probably a thousand different approaches you could take.

Through tenon or one that's going to be hidden? If hidden I'm not going to worry about it perfectly bottoming out (the strength is mostly in the cheeks and shoulder anyways) and trim it a little shorter anyways, good use for a gent or japanese hand saw. A belt sander is also great if you want to really sneak up on a fit like that. Trimming the end of a tenon on a tablesaw seems like it is just begging for it to split or tear.

For a through tenon I'd make that end-grain cut using a chisel over a plane, as you've got more control and the body of the plane is just getting in your way. If it's finessing the end of a smaller board I'd grab a small block plane, for me that'd be a LN 102 or a little 1" wood-body. I find the bigger number 60's are usually too unwieldy to get a good smooth cut, but I'm not sure what you're using.

[curlyoak]

If it was a through tenon and the tenon is to be smooth with the surface, then I would want it long. Sander of a variety of types will even it up real quick. You need to explain the joint for a better answer.

[Jonathan McCully]

19 minutes ago, curlyoak said:

If it was a through tenon and the tenon is to be smooth with the surface, then I would want it long. Sander of a variety of types will even it up real quick. You need to explain the joint for a better answer.

Sorry for not being more clear. What I've been working with is some 3/8" panels that will be fitting into a frame as well as some integral tenons (not through). As I wanted to sneak up on a perfect fit, I left them all just a touch long, but when I got down to fitting them, I was having trouble deciding the best way to do it. My LN rabbeting block plane didn't want to cut the end grain of either the panels or the tenon cheeks very easily (again, might be a sharpening issue), and I thought that my ROS might leave some noticeable valleys in the panels, so didn't want to use that. Still new to a lot of this, so trying to learn the best way to do some of these things without cutting pieces exactly to length as I fear that it will end up too short. Hope that helps.

[curlyoak]

Non through tenons as already explained above will never be seen and a little shorter usually doesn't matter. When making the tenon and not through I always make it a little shorter. My domino designed to cut depths matching the dimensions they make the dominoes and the depth on the mortice is always a little extra.

[Chet]

I always have non through tenons a little short like mentioned above.  Partially because you don't want and hydraulic resistant from the glue in the bottom of the mortise during the glue up.

For precise trimming a shooting board and jack plane can be a good way to go.

[Coop]

I put mine on the ts, nestled against the miter bar and with the saw off, gently press the end of the board/tenon against the saw blade. Hold the board firmly against the miter bar and pull the board back to you. Now turn the saw on and run the board thru the blade. You may have to do this more than once until you’re satisfied. 

[Tom King]

I use the Radial Arm Saw.  It's always ready to go, and has a stiff blade on it that doesn't deflect.

[Don Z.]

My first thought would be to quote Shannon:  "Sharp fixes everything."  That may in fact be the problem with your block plane.

My go-to in a case like this, however, would be my low-angle #5 and a shooting board.

For the tennons, though:  It's not a through tennon.  The strength is in the cheeks, a little short will not matter.

 

[JohnG]

If you want the TS to be more precise, you can use a miter gauge with a stop block that has micro adjust, or you can use shims/feeler gauges and a stop block to take off small amounts without the ‘guesswork’

[gee-dub]

Just adding credence to what others have said.  Tenon strength is in the cheeks and you want room at the end for glue.  Micro adjustments are easily done at the shooting board but non-show tenon ends don't require that level of accuracy IMHO.  Stop blocks with micro-adjuster or slipping pieces of paper, metal sheet stock or old gift cards between the work and a non-adjustable stop block allow you to fine tune at the machine.  I am much more comfortable with a bit of room at the end of a tenon than I am with a poor sidewall fit.

[Chestnut]

To fit a board to an opening I usually use a knife. I hold the board in place and make a knife mark where it needs to be cut. I then cut a hair long and go back and forth between the saw and the project doing the following.

To trim a hair, with the saw off, i slide the part against the saw plate, then i let the blade up on my miter saw or pull the miter gauge back on the table saw and turn the saw on then make the cut. It trims a very tiny bit, about what a thick plane shaving would be. I do this a few times until it fits perfect. If i need to make a heavy trim i push against the saw plate a bit, this deflects the blade and makes a heavier cut.