Adjusting a Langdon mitre box

[Jim Van Verth]

So last night I tried to fettle my Millers Falls miter box and ran into a couple of issues. First I tried to calibrate the cutting angle at the 90° mark. I initially measured the angle of the saw compared to the back of the box, but when I tried to cut a 45° angle it wasn't quite right. Then I tried to use the grooved bar under the saw (the gib, I guess?) as a reference and that clearly wasn't correct either. I'm guessing I need to take a series of cuts and tweak the adjustment based on that? The Langdon reference page is gone so I'm not sure what the right approach is.

The other issue I discovered is that it doesn't cut exactly vertically. I'm not sure if that's due to the saw set or the box itself is out of alignment in some way. The base plates are from a different box since they were in slightly better shape but I can't imagine that's it, and the rest of the parts are original to this box. Could be my technique I suppose, but I thought the box was supposed to compensate for that. Is there a good way to narrow down the cause?

[Mel Fulks]

I guess it's possible the saw has more set on one side. Some of those boxes have a lot of wear on the guides .

Hey guys: NEW CONTRIBUTOR NEEDS A LITTLE HELP

[Jim Van Verth]

Oh yeah -- the saw's not original to the box either.

[Jim Van Verth]

And thanks -- that's given me one idea. I can try turning the elevators 180° and see if it still drifts in the same direction. Sawing from the back instead of the front might let me figure out if it's the saw vs. anything else, though that would be awkward.

[Jim Koepke]

I tried to calibrate the cutting angle at the 90° mark. I initially measured the angle of the saw compared to the back of the box, but when I tried to cut a 45° angle it wasn't quite right. Then I tried to use the grooved bar under the saw (the gib, I guess?) as a reference and that clearly wasn't correct either. I'm guessing I need to take a series of cuts and tweak the adjustment based on that?

Yes, adjust the miter box to how it cuts the work.

There is a manual available here: http://www.badaxetoolworks.com/pdf/MFLA_MiterBox.pdf

jtk

[Tom M King]

I bought mine new, already assembled, off the shelf of my favorite building supplier (out of business in 1992), and have never touched any adjustment on it. It still cuts true after about 45 years, but I never broke any of my toys when I was little either.

[Jim Van Verth]

Someone else broke this particular toy. I probably shouldn't have bought it in the condition that it was in, as it's been nothing but grief. But I've cleaned it up and got a saw for it, and am just trying to get it back into fighting shape. When I was a babe I must have been cursed to find broken things and be compelled to fix them...

[Charles Guest]

Except on fairly narrow workpieces, you aren't likely to get a fit right off a manual miter box saw that is as good as it could otherwise be after being shot in a vice or on a shooting board. Don't send yourself on a fool's errand. If you manage to get it adjusted perfectly it's unlikely to stay that way for long, as the saw gets dull, parts continue to wear, etc.

[steven c newman]

Hmmm..use mine all the time, up to 1 x 8 planks...Langdon No. 75
side view.jpg
$25 garage sale item, this is what came home with me....
saw.jpg
And, after a bit of rehab. saw is marked with a Millers Falls triangle decal on the handle.
saw is also a 5 x 30" back saw, made expressly for this saw by Disston ( says so right in the readable etch)

Have never needed to "shoot" any cuts that came off this miter saw. 90 degrees or 45 s are spot on.
scale.jpg
Quadrant scale can be adjusted to fine tune, loosen the bolts a tad, shift the scale a needed. Adjust the keepers to keep the saw from rubbing the gib.
45s.jpg
The shorter ones control how close to the gib the blade of the saw gets..as a saw is sharpened, you need to lower these a bit..
90.jpg
These longer ones are depth stops...I set these for doing shoulder cuts on tenons
label, handle.jpg
YMMV..
box label.jpg
A view of the labels, and note how far above the groove in the gib the saw is.
Mitre box has stayed dead on adjusted....and in use.

IF your saw gets dull too quickly...you are cutting into the gib, raise the stops...like they are supposed to be set. groove is to clear sawdust away....NOT to "guide" the saw.

[Charles Guest]

Hmmm..use mine all the time, up to 1 x 8 planks...Langdon No. 75
side view.jpg
$25 garage sale item, this is what came home with me....
saw.jpg
And, after a bit of rehab. saw is marked with a Millers Falls triangle decal on the handle.
saw is also a 5 x 30" back saw, made expressly for this saw by Disston ( says so right in the readable etch)

Have never needed to "shoot" any cuts that came off this miter saw. 90 degrees or 45 s are spot on.
scale.jpg
Quadrant scale can be adjusted to fine tune, loosen the bolts a tad, shift the scale a needed. Adjust the keepers to keep the saw from rubbing the gib.
45s.jpg
The shorter ones control how close to the gib the blade of the saw gets..as a saw is sharpened, you need to lower these a bit..
90.jpg
These longer ones are depth stops...I set these for doing shoulder cuts on tenons
label, handle.jpg
YMMV..
box label.jpg
A view of the labels, and note how far above the groove in the gib the saw is.
Mitre box has stayed dead on adjusted....and in use.

IF your saw gets dull too quickly...you are cutting into the gib, raise the stops...like they are supposed to be set. groove is to clear sawdust away....NOT to "guide" the saw.

Mitres on fine furniture get shot, it's as simple as that. If you've honestly found a manual saw that cuts them perfectly then thank your lucky stars. Nice pictures of the saw, how about some of the mitre joints it has cut? For a manual saw to work perfectly not only does the jig (the box) have to be perfect but the saw plate, the filing, and the set. That's a lot of stuff to come together all at once. If the saw plate has any amount of wave at all the mitre cannot be a perfect fit. Ditto any play in the box, too much pressure when sawing, etc., etc.

People reading this thread need to understand that the saw gets you close, but a plane closes the deal and the joint.

[Kurtis Johnson]

You're rescuing industrial art from an inglorious end at the landfill. Even if you're forced to fabricate bits of brass, it's a worthy pursuit.

There are garages, barns and pastures full of rusty card that will never run again - you get to use yours.

+1

Jim Van Verth: When you say it was broken, was a post or any other cast part of the box fractured and glazed back together? If so, very common, unfortunately. I don't need to mention cast iron is very heavy and vulnerable. If this is the case, it might explain why you are having trouble fine tuning it. It might have deflection built into the repair which would be a bear to overcome. I have two I collected used, and both cut absolutely perfectly square from the start after I blew off the cobwebs and have required no tuning, just cosmetic stuff. Just an fyi.

[steven c newman]

Depending on the skill of the user....have no issues with mine...

[Charles Guest]

Depending on the skill of the user....have no issues with mine...

Sounds lovely I'm sure to the uninitiated, which I am not though I sometimes wish I were. Anybody buying one of these and expecting perfection, or spending the amount of time fiddling and futzing to achieve a fleeting perfection, are in the throws of a large waste of time. Get it close, take two shots with a plane. Voila.

These are essentially a joiner's tool ('trim' carpenter's) saw. A shot with an apron plane, plus the thickness of paint, and a joint eleven feet from the floor = 'perfection.'

[Jim Van Verth]

Jim Van Verth: When you say it was broken, was a post or any other cast part of the box fractured and glazed back together?

Fortunately not -- it was just extremely rusty and missing some parts. Vinegar took care of the first and another incomplete box the second.

[Phil Mueller]

Jim, I use mine primarily for sawing the miters for boxes. As such, the miter is usually about 3-31/2” vertical. I find it rarely perfect off the saw (although I have had a few occasions where I could glue up off the saw). Funny thing is that it is less off when I use the 45 detent on the right, versus on the left. I’m talking about a 32nd at most over the 3 inches or so. Nothing a few swipes on a shooting board won’t correct. And I usually need to take a few swipes anyway to get the opposite sides the exact same length.

Don’t know if it’s the box, the saw or saw set, or my technique, but the effort to correct it isn’t enough to justify trying to get it perfect.

With all that said, I did have a Stanley box at one time that would saw out about an 8th-16th inch over the 3” inches. That drove me nuts and I tried everything including wedging the bottom board to try to correct it. Never did get it anywhere near as close to the accuracy of the MF box. So yes, some are more accurate than others, but I don’t think I’d spend too much time trying to get it perfect. While some seem to have acquired a perfect box, I think it’s just the nature of the beast.