Are your TS miter slots parallel?

[Lisa Starr]

Hi all, I was just giving my TS a once over as it has been a while and I've been struggling with some of the cuts. I had better measuring tools than usual and made the discovery that the two miter slots aren't exactly parallel. Mind you, I would consider the .003" they're out "minor" for woodworking equipment, but I'm still curious as to the results vs other saws.

On a separate note, I found that my arbor and mounted flange are running true, but my go to blade is slightly warped. I'll have to decide whether to replace the blade or try to have in straightened.

[Jim Becker]

Some shops can straighten a blade, but if it's not relatively new, it may be more cost effective to get a new high quality blade. (You didn't mention what blade it is) Honestly, it's best to have two of your primary blade anyway, so you have one available while another is out for sharpening, etc.

[glenn bradley]

On the miter slots, I've never measured but, my various dual runner sleds all run well with no play so they are close enough for that. If the blade is at the upper end tier and has a half dozen or so sharpenings left I would definitely have it trued up. IF it is a sharpening or two from the end of its life I would just replace.

[Lisa Starr]

Blade is a Freud Combo (can't remember the number and too lazy to walk out to the shop), but it probably only has 1 or 2 sharpenings left anyway. I have an identical one that is much newer and measures flat both on and off the saw. I'm sure I'll just use the warped one for "roughing" work until it is dull this time and then toss it.

[Brian Holcombe]

By what method are you determining that they are out?

[Lisa Starr]

I placed a square ground bar in the left slot and mounted a dial test indicator to a bar in the right slot. As you slide the right bar from the front of the saw to the back, they "spread" by .003". Not much, but out. I double checked this result both by checking the each slot to the rip fence and each slot to the blade. Of course, over the distance of the blade, it is only out tenths.

[Brian Holcombe]

Interesting, sounds like you’re getting a repeatable result. Not much you can do to repair the issue, but in any case I think .003” is very good over the length of the bars.

[Edward Dyas]

Hi all, I was just giving my TS a once over as it has been a while and I've been struggling with some of the cuts. I had better measuring tools than usual and made the discovery that the two miter slots aren't exactly parallel. Mind you, I would consider the .003" they're out "minor" for woodworking equipment, but I'm still curious as to the results vs other saws.

On a separate note, I found that my arbor and mounted flange are running true, but my go to blade is slightly warped. I'll have to decide whether to replace the blade or try to have in straightened.A lot of times people have problems with their machinery because they use machinist tools to check it. If you measure the slots with a tape measure I think you will find the miter slots are parallel. .003" isn't enough to be a problem even with a sled.

It's too late now but if you get a blade hot enough to warp leave the saw running for a minute or so until the blade cools and it usually straightens itself out. Unless it's a high dollar blade I would just toss it.

[Brian Holcombe]

A lot of times people have problems with their machinery because they use machinist tools to check it. If you measure the slots with a tape measure I think you will find the miter slots are parallel. .003" isn't enough to be a problem even with a sled.

It's too late now but if you get a blade hot enough to warp leave the saw running for a minute or so until the blade cools and it usually straightens itself out. Unless it's a high dollar blade I would just toss it.


:D Indeed, the cause and solution to most of my problems.

[Lisa Starr]

Yep...I was born and raised in a machine shop (and can run most machines). It is a blessing to be able to bring high quality measuring tools home for specific tasks, but I frequently have to remind myself I'm working with wood as I automatically want to work in .001"! As I said in my OP, .003" doesn't concern me, but I was curious if other table saws are also not quite parallel.

[Mike Cutler]

I'm fairly certain that with all things, there will be a manufacturers tolerance.
Nothing at all wrong with applying machinist's standards to check and align any machine. Trying to cut the wood within .003 is a little excessive, but checking machines to that tolerance is fully justifiable.
I'm fairly certain that the miters on my table saw are "close enough", but since I don't really use them, I've never checked.

[Brian Holcombe]

Entirely agree, a tape measure is something I use for rough work only. I don’t find a tape measure to be useful for measuring work pieces but they are repeatable so decent for corner to corner measures. I don’t recall if we even had a tape measure at the machine shop and I generally build without one.

It’s actually fairly common that we’re working to a high degree of accuracy but often remain unaware of it. Working with stops, utilizing reference faces and creeping up on a fit are all ways of doing so. A very tight mitered corner on a box, as example, can gap with a single plane shaving.

[Jim Becker]

I wouldn't sweat a small deviation like that unless there was a specific thing that it causes problems with, such as a sled that uses both slots and has very tight runners or if you regularly use both slots and cut on both sides of the blade. I suspect the majority of folks "only" use the leftward most slot the majority of the time, so if that slot is parallel to the blade as much as possible, that's going to be satisfactory. Using one side also helps reduce the variances, too.

[Mike Cutler]

Entirely agree, a tape measure is something I use for rough work only. I don’t find a tape measure to be useful for measuring work pieces but they are repeatable so decent for corner to corner measures. I don’t recall if we even had a tape measure at the machine shop and I generally build without one.

It’s actually fairly common that we’re working to a high degree of accuracy but often remain unaware of it. Working with stops, utilizing reference faces and creeping up on a fit are all ways of doing so. A very tight mitered corner on a box, as example, can gap with a single plane shaving.

Brian

Definitely agree!
There is nothing wrong with persuing accuracy to accomplish good work. Nothing at all.
Many years ago I had a friend that ran a custom frame making shop. Not the type of shop for family portrait frames and such, but frames that are hanging in the Met,Guggenheim. Smithsonian, and many others. His two principal machines were DeWalt compound miters. He had a whole shop full of all of the "normal" frame making machines, but it was those two DeWalt's that were his foundations. His secret ??He had a retired machinist from Electric Boat that set those machines up for him, and custom ground those blades. In the Mid 90's his blades started out at over $300.00 and then he turned them over to the machinist to fine tune them.
Those two Home Depot bought DeWalt's looked really out of place in his shop, but he told me that even he never adjusted them.
Another person I met many years ago was Nicolai Medvedev.His "boxes" started out at $250,000, and easily surpassed the million dollar mark, and that was twenty years ago! .003 would be a huge error to Nicolai.
Doing fine work, requires fine tools.

[Jacob Mac]

My miter slots aren't parallel. Drove me crazy, but I decided to obsess over a project instead of my saw and I am better off for it.

[Mark Daily]

Yep...I was born and raised in a machine shop (and can run most machines). It is a blessing to be able to bring high quality measuring tools home for specific tasks, but I frequently have to remind myself I'm working with wood as I automatically want to work in .001"! As I said in my OP, .003" doesn't concern me, but I was curious if other table saws are also not quite parallel.
Just to keep things in perspective, a sheet of 24 lb paper measures .004”. :D

[Doug Dawson]

Entirely agree, a tape measure is something I use for rough work only. I don’t find a tape measure to be useful for measuring work pieces but they are repeatable so decent for corner to corner measures. I don’t recall if we even had a tape measure at the machine shop and I generally build without one.

It’s actually fairly common that we’re working to a high degree of accuracy but often remain unaware of it. Working with stops, utilizing reference faces and creeping up on a fit are all ways of doing so. A very tight mitered corner on a box, as example, can gap with a single plane shaving.

In fact, you can build an entire piece of furniture from start to finish without any measuring at all, using a story pole. And have it repeatable.

[Bruce Page]

Lisa, .003 is very good. What make & vintage is your saw?
Your post got me curious about mine. I used a more direct inspection methodology on my 20 year old Unisaw. It showed .000 on both front & back ends but drifted off .003 in the center. I can live with that.

[Lisa Starr]

Bruce, Believe it or not, it is a 2005 Grizzly G1023Z that I purchased new. I think I was lucky, because this particular saw seems to be very accurate.

[Mark Daily]

Bruce, Believe it or not, it is a 2005 Grizzly G1023Z that I purchased new. I think I was lucky, because this particular saw seems to be very accurate.
I have the G1023SL purchased the same year. Very accurate, solid and trouble-free.