Fine tuning a mitre box that doesn't cut vertically correctly

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Forum topic by kevinw posted 07-14-2012 10:06 PM 3137 views 0 times favorited 20 replies Add to Favorites Watch
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199 posts in 5020 days

07-14-2012 10:06 PM

Topic tags/keywords: mitre mitre box fine tune hand tool miter saw

Hoping someone here can help me figure something out. I use an old mitre box a lot (not a chop saw) and I cannot seem to get a square vertical cut on it. I have shimmed the wooden base and when I check it with a square to the blade it is square. But when I make a cut it is never quite vertical

See this pix for better explanation:[email protected]/7570623874/

The top view on the 45 degree angle is fine:[email protected]/7570629684/

Any suggestions?

-- Kevin, Blue Springs, MO

20 replies so far

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#1 posted 07-14-2012 10:11 PM

Maybe it’s the saw ? If the teeth on one side are damaged it will likely go off course despite your best efforts.

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

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2877 posts in 3492 days

#2 posted 07-14-2012 10:14 PM

It probably has to do with the wood moving while cutting it. Maybe try clamping the wood so it cannot move.

-- You can collect dust or you can make dust. I choose to make it.

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1899 posts in 4842 days

#3 posted 07-15-2012 03:00 AM

No expert on these machines, but I’d guess the saw isn’t set correctly -i.e one side has more set than the other resulting in the blade wandering.

-- Joe

View thedude50's profile


3613 posts in 3759 days

#4 posted 07-15-2012 07:51 AM

Is this a hand saw miter box do you have a full sized photo of the box does it have rods that are supposed to keep the saw aligned I am thinking this is what your talking about but want to know before I waste my time on the wrong saw

-- Please check out my new stores and

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13722 posts in 4622 days

#5 posted 07-15-2012 08:56 AM

could be your stance too
like your eye is over the cut
and your shoulder to the side
making for a slightly ‘pulled over’ stroke

the guides may be worn too
from years of service
or like the dude says
the posts got tired
and are sagging to the right

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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199 posts in 5020 days

#6 posted 07-15-2012 01:29 PM

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#7 posted 07-15-2012 02:08 PM

I haven’t used one of those for years, but wonder if the saw guides are in good contact with the saw blade on both sides. They need to be close enough to eliminate blade “wobble”, but loose enough to allow the blade to travel without binding up..

If they’re worn enough they may not work right.

-- Adversity doesn't build reveals it.

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199 posts in 5020 days

#8 posted 07-15-2012 06:13 PM

In case everyone wonders why I don’t use a chop saw, the answer is that I make lots of very small boxes (2” x 4” for instance), and it just doesn’t feel safe to me to use a power tool. Have messed around with limited success making jigs for my table saw as well as they are either not accurate enough or feel unsafe at these small sizes.

-- Kevin, Blue Springs, MO

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3613 posts in 3759 days

#9 posted 07-16-2012 09:46 AM

first off looks nice ok i am of the theory that the bushings in the sled are worn or the guides are too loose I think you should check that the rods are plumb as well also critical is the work surface must be level .///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

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17571 posts in 3899 days

#10 posted 07-16-2012 10:23 AM

Doesn’t look like those rods are adjustable as older ones are via set and adjusting screws. Might be some play in the steel saw guides as well, that bending can cliose up. May have to start looking for an older box, too, that can address these problems

-- Don't anthropomorphize your handplanes. They hate it when you do that. - OldTools Archive -

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3613 posts in 3759 days

#11 posted 08-01-2012 04:06 AM

did this problem ever get resolved did you look at what i recommended

-- Please check out my new stores and

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199 posts in 5020 days

#12 posted 08-01-2012 12:45 PM

I haven’t resolved it. As a temp fix made a old fashioned wooden u shaped mitre box and getting good results with that with same back saw, so feel that eliminates questions about stance, saw sharpening, etc.

Bed is level and saw is square to bed. Hard to tell if rods are plumb as not a good surface to test off of, but they seem to be plumb as best I can tell. If they are not, how would I adjust them? I don’t see any way to do so other than maybe shimming somehow.

Not sure it has bushings. Where would they be located?

-- Kevin, Blue Springs, MO

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3613 posts in 3759 days

#13 posted 08-02-2012 03:02 AM

the rods on my box are held in brass bushings. if they are loose your cuts will be bad. if the rods are bent the same thing. try to take the rods out and roll them on your table saw. if they aren’t flat you will see them wobble, after you try this let me know what you find.

-- Please check out my new stores and

View Loren's profile


11306 posts in 4929 days

#14 posted 08-02-2012 03:18 AM

You might want to invest in a Lion or similar miter trimmer –
the cuts you get are dead-on. In the old days mitering
with a saw was unreliable and end grain would routinely
be squared using various forms of miter trimmers and
shooting boards.

View Johnnyblot's profile


319 posts in 3557 days

#15 posted 08-02-2012 10:10 AM

Following on from Loren’s comments which I agree with: -
My approach, to get the accuracy you are looking for, would be to saw (as you are doing) to a knife line, cutting just shy of the line in the waste side. Then with a shooting board and plane sneek up onto the knife line.

I know this will take longer but the accuracy you can achieve is much better IMHO.

The great thing about gauge and knife lines is that they leave behind a mark or “polished track” that you can see easily.

I hope this is of some help.


-- Gossamer shavings just floating around the back yard….-Bandit

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