I'm wondering what tolerence one uses when cutting pieces in general.
I am currently making an end table from pine as a prototype for the 2
real ones for the LR. I can usually cut boards to 1/32 of an inch of
what I had on my plans, but when assembled, I see small gaps or areas
that I have to plane down.
I rather enjoy the "extra" woodworking, but am wondering if this due
to being a poor woodworker, or if this is normal procedure. Same
thing with right angles. I set the table saw up with a machinist's
square, and a "tight eyeball", and get pretty good results, but can
still get a 1/16 inch error on a 24 inch square board.
What do you guys get on the average?????
I think with stable and well tuned equipment one can typically hold
better than a 32nd over 24 inches. Larger spans become a challenge.
Regadring gaps and "plane to fit" type situations, the best approach
is to "design in" methods of fit so you have a plan about how all
critical fits will work and can be gauged as milling and fit-up
progesses. Yes. miters often need to be trimmed to fit well but hiding
edge gaps under moldings, utilizing rabbet ledges to let butts hide
under an overhang and keeping a shoulder plane on the bench and having
some filler on hand and learn about burnishing to push the edges of
wood around when needed all server to make it all look good in the
For me a cardinal rule is to cut every item as true and square as
possible and fix things along the way. This is where we have the
debate sometimes about using that shiney miter saw for a finish cut vs
doing all possible finish cuts on the TS. I always use the TS where I
have more control, vs relying on a miter saw for instance.
On Feb 12, 9:07 am, firstname.lastname@example.org wrote:
On Feb 12, 12:07 pm, email@example.com wrote:
Keep at it and you'll continue to get better.
I try as much as possible to 'production cut' everything. Doing
things like cutting all of the similar rabbits or tenons at the same
time gives you consistency when fitting the mortises or vicey-versey.
Anytime you need to reset the fence, blade height, angle, etc. you are
allowing for error.
As far as being out of square I use a panel cutting sled to square up
panels. Once you take the time and make all your test cuts when
building the sled you'll never have problems again.
I use a simple one like this:
(without the runner on the edge of the saw)
But some go with a double runner sled:
Something's not set up to have that much error in 24" -- have you
verified the miter slot is actually parallel to the blade? If it isn't,
even though the miter gauge is perpendicular to much higher tolerance,
the panel will "move" towards or away from the plane of the blade as it
paraphrased from Tolpins book "Workshops"
carpenters work to the nearest 1/8", furnituremakers to the nearest 1/64"
and boat builders to the nearest boat.
That advice given, strive to continually get better and you will.
Personally, I'm constantly striving for my tolerences to get better or my
eyesight to get worse.
I used to make all my own bee hives. There are 9 or 10 frames (of 4
pieces each) per super, so there are a lot of pieces to make over and
over again. I was able to hold +/-0.003 in dry pine to make all the
parts. Table saw and router where the main cutting tools.
On Thu, 12 Feb 2009 09:07:24 -0800, cwo4cno7325 wrote:
This reply is a bit OT:
The goal is not the tolerances you want, but in finding the source of the
errors. Eliminate, reduce, or control the sources of errors and the
tolerances will take care of themselves.
I know that sounds like some Monthly Quality meeting in the lunch room
BS, but it is true. Why is your saw giving you 1/16 inch error on a 24
inch board? Why are there gaps in your assembly? The longer you are in
woodworking, the more you will find out about your tools and the sources
By learning to think through the process you are using to cut shape the
wood you will find the sources and by trial and error learn how to
control the sources of error. You will then learn a lot more about your
hobby and yourself.
BTW: 100 years ago, in woodworking the greatest source of error was lack
of practice in using hand tools. Nobody today has the time or
inclination to serve many years as an apprenticeship learning to use hand
tools. We trade money for power tools, jigs, fixtures, and carbide
blades instead of spending time doing very boring and repetitive tasks.
But even back then, thinking through a problem to reduce the causes of
errors was an important part of learning woodworking, IMHO.
Now back to other replies that may actually help you.
On Thu, 12 Feb 2009 09:07:24 -0800 (PST), firstname.lastname@example.org wrote:
Working with wood is very different than metal or plastic. Wood moves
so we often use joinery that overlaps, slides past each other, etc. To
check to see if two boards are the same length, I'd butt them up to a
stop. If I can not feel a step on the other, I say, for all practical
purposes that they are the same length. A 1/16" error is telling me
the table saw is in need of a tuneup.
I don't think you can do better than this book for table saws. It will
guide you through some of the setups the guys are talking about and help
you tune your saw. Of all the woodworking books I own, this is in the top 5
Kelly Mehler describes the topic very well, and is a wealth of knowledge.
Thanks for a ton of good ideas! I think I have all tools well tuned
up, and I may have overstated the 1/16 inch error. That 1/16 inch
usually comes from the combination of a number of parts, each with a
very small error that when added together may yield a total 1/16 inch
error at most.
One thing that I have found that helps is to cut all the same size
pieces at the same time, as mentioned above. They may not be exact in
dimension, but they are the same!
The tolerences mentioned for house carpenters, and furniture makers at
1/64 is a good target. I think if I can get 1/64 from the power
tools, then I can "fix" things with hand tools during assembly, to MY
And practice! I just looked at one of my first projects, a wood box
for camping, done on a Workmate, with a really bad circular saw. It
looks "very authentic" and at least shows some improvement when
compared to current projects.
Anyway, thanks for all the help.
On Fri, 13 Feb 2009 08:42:35 -0800 (PST), email@example.com wrote:
Cumulative error is a bit stickier problem. You would think that the
errors would tend to go at random directions, effectively cancelling
each other out over the entire project, but I tend to find that they
always are strictly additive, leading to sometimes rather significant
error at the end.
No answers for you, but you are not alone.
"We need to make a sacrifice to the gods, find me a young virgin... oh, and
bring something to kill"
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