Squaring up a mitre saw accurately

[RinkyDinky]

Haven't posted for a while but always read the forum on a daily basis.

I am fortunate enough to have a Festool Kapex mitre saw and have used an excellent method to square the cut.

I accept that this method is probably overkill for cutting wood, but my engineering background always used these methods and i do have a passion for accurate tools!

I have not seen this method discussed on the forum and if it has, i apologise beforehand, but it may help someone.

I always used to check square by butting up an engineers square up against the blade from the fence and adjusting as necessary:

After removing the power to the saw, and locking the blade so it does not rotate, i check the square of the blade to the base, using a Wixey gauge as in the pic:

Next, clamp a square, the bigger the better, this one is 18" against the fence, that lies parallel to the blade.

Then attach a Dial Test Indicator with magnetic base to the blade and adjust it so that it is zeroed at the fence end of the saw:

Then run the head of the saw along the blade towards you, along the square noting the change in reading on the dti.

Mine read just .010" after using the five square method i had used up till now, but i found that using that method, i had varying results and of course, used lots of wood up that could be used for other things.

The adjustment on the Kapex is on the front scale and is achieved by simply undoing this, and moving the head to zero the dti, then re check.

Mine now is reading under .001" over the full travel, that's near enough for me (!)

I would be interested to hear your thoughts and opinions, and hope that i am not missing anything obvious....

I have used a similar method on my table saw and the accuracy have achieved is quite exceptional after a bit of fiddling.

 

[TonyW]

You mean to tell me after spending all that money on a mitre saw you actually have to set it up, and there is a chance that it may go out of perfect alignment in the future :shock: :lol:

Seriously though, thanks for posting this - I need to check and set my mitre saw so this tutorial will prove very useful.

Cheers
Tony

 

[Chems]

What about variation of your measuring tools and their deviation. Surly none of them are 100% accurate to the last decimal point. Could your 0.1 be a combination of these? I'm just asking out of pure interest as this appeals to my OCD side.

 

[RinkyDinky]

Thanks for the replies.

I expected the saw to be cutting well out of the box, but always check anyway, hoping that it is not a friday afternoon type jobby, and yes, i do think it is some sort of OCD as i have sold equipment in the past that flexed too much to align properly :lol:

I expect errors in my measuring equipment, the square was about £20 so not really a precision instrument, but i have checked it using the time honoured flip over method and it's as appears spot on

Funny how we go back to traditional methods even with flashy equipment.

To ensure accuracy from the dti's, I have both an analogue and digital dti from past employment days and the errors check out with similar figures.
Incidently, I still measure in inches and thous' :?

 

[p111dom]

Haven't posted for a while but always read the forum on a daily basis.

I am fortunate enough to have a Festool Kapex mitre saw and have used an excellent method to square the cut.

I accept that this method is probably overkill for cutting wood, but my engineering background always used these methods and i do have a passion for accurate tools!

I have not seen this method discussed on the forum and if it has, i apologise beforehand, but it may help someone.

I always used to check square by butting up an engineers square up against the blade from the fence and adjusting as necessary:

After removing the power to the saw, and locking the blade so it does not rotate, i check the square of the blade to the base, using a Wixey gauge as in the pic:

Next, clamp a square, the bigger the better, this one is 18" against the fence, that lies parallel to the blade.

Then attach a Dial Test Indicator with magnetic base to the blade and adjust it so that it is zeroed at the fence end of the saw:

Then run the head of the saw along the blade towards you, along the square noting the change in reading on the dti.

Mine read just .010" after using the five square method i had used up till now, but i found that using that method, i had varying results and of course, used lots of wood up that could be used for other things.

The adjustment on the Kapex is on the front scale and is achieved by simply undoing this, and moving the head to zero the dti, then re check.

Mine now is reading under .001" over the full travel, that's near enough for me (!)

I would be interested to hear your thoughts and opinions, and hope that i am not missing anything obvious....

I have used a similar method on my table saw and the accuracy have achieved is quite exceptional after a bit of fiddling.

 

[busy builder]

Do you take into account any warp in the blade ? or inaccuracies in the travel tubes that the saw body runs on ?
What do you do about mitre, compound etc cuts ?
or the machining of the actual saw body ?

Sorry, but I think you need to get a life !

 

[RinkyDinky]

I have a fine life thank you very much. Comments like that are not appreciated. :roll:
Comments like that are what made me not bother posting my views in the past.
I do not see a problem with getting something right, then checking it again maybe several months later after much use and woodworking to ensure all is still accurate. As for the 45 degree cuts etc, i rely on the 90 degree setting to ensure that the rest follow.

I accept that there are inaccuracies in equipment, rails etc. etc. but still feel that this is a good way to align a saw.

I have no problem with a cut being ten or twenty thou out over it's length, but if there is an opportunity to get it about right, then why not?

 

[wizer]

yes a little harsh there BB

It's horses for courses. Personally, I applaud the patience to set something up to that degree of accuracy. I really wish I had the patience. But, for me, even setting the P/T knives drives me INSANE. That said, I think I learned something yesterday when I did that, so it was useful in a way.

 

[RinkyDinky]

Thanks p111dom for getting the pictures right! I tried for ages to do that but could not get it to.

Forums are supposed to be a melting pot of ideas and thoughts, where we are supposed to help each other with things that are opposing us, or to give us an incentive to try something new or a warning to avoid doing something.

I have just shown MY way of doing this, may not be necessary if you chop 4 x 2's on site but is certainly worthwhile for cabinet making where errors appear amplified.

I am sure my method is flawed in many ways, but my cuts are very very square

 

[Derek Willis.]

Wizer,
Off subject, you say setting your p/t blades is a pain, I always found the same until the last time I did it, more than simple, the thicknesser now sings when in use instead of moaning at me, you always discover where you went wrong in the end and what a joy when you do,
As for setting up the m/saw, yes a little over the top, but, if it suits you then do it.
Derek.

 

[newt]

Rinkydinky, This looks like a good way to check the accuracy and saves a lot of wood. It would have been interesting to have cut say a 6 inch piece before and then after to see if there is any change when checking for 90 degrees using the same square. We should all attempt to rid ourselves of machining errors.

 

[wizer]

That method would be great in measuring the amount of 'slop' in the bars at full extension.

 

[OPJ]

I think this is a great tip, thanks for taking the time to share it.

I also struggle to set my fence up square to the blade - part of the problem is that need a larger square! :roll:

I find my Bosch saw to be accurate enough for cuts up to about 6" wide. With the saw at full stretch though, I'd expect just about any sliding mitre saw to show some discrepancy.

Setting the planer knives is the other bane in my workshop! What you really need is a decent jig... I've found that with practice and patience, I can get those Chinese magnetic jigs to work for me very well. I think I struggle with te on that came with my machine because it's so light weight... It does help if you secure them near to their correct position, lightly nip up the bolts and then give a final push in to place. :wink:

 

[wizer]

Honestly, don't get me started on P/T blades. Up, Down, Up, Down. In the end I surmised that my blades are convex! Still, they plane wood fine as far as I can see so I must not obsess.

 

[Derek Willis.]

Iguess this discussion can go on forever, but if you find a way to set them, then stick to it no matter what!!!
I am very happy with mine!!!
Derek.

 

[Chippyjoe]

Rinky Dinky, Thanks for your informative ideas on setting up your mitre saw.
I have been thinking of buying a wixey gauge (have seen them on e-bay) and I was wondering how accurate they are?
Any help on this would be appreciated.
Regards, Mark.

 

[wizer]

indeed, it turned out not to be the method, but convex blades (I think).

 

[Derek Willis.]

Wizer,
I have now been able to perfect the sharpening of my blades, together with my newly profound ability to set perfectly I am so proud and pleased you won't believe it!!!
I do use a Veritas jig to sharpen.
Derek.

 

[joiner_sim]

In the shop I work in, I regularily make bay windows. Its okay when working to a setting out board, because the bay is..... lets say 35.2 degrees. As You can check the cut on the setting out. But when you get a sqaure 45 degree bay, I tend to just take it for granted that it is 45 degree. Although it never is once its been cut.

If I had the patience to do the method shown, I think I'd try and fix the saw at work. The reason I don't really bother about it though, is because the saw was £600-£700. And its still not perfect.

 

[wizer]

so what do you do to correct the 45 mitre?