The Quest Toward a Square Cut on a Kapex

[Brian Holcombe]

I bought this saw early 2017 assuming that some of nice German engineering would serve me well. After-all, on the whole I enjoy my Festools. I could square the saw, but I found it to come out alignment quickly. I decided to pursue some changes.

I had two goals, create zero clearance so that small objects do not turn into missiles and so that I can line my cuts up to a knife mark. The other goal is to cut square without regular readjustment.

When adding an auxiliary fence it's important to note that it can cause more issues than it cures. Cutting square starts with having a fence that is true, flat and both sides must match and be aligned to one another. I started with a set of aluminum plates, I drilled and tapped for bolts then shimmed the fence until they were in fact true and aligned.

Finally I could then square the saw up to the fence, however I've noticed that with this saw it does not remain square. Any heavy cuts usually throw it out of alignment and so after realigning this thing more times than I care to recall I finally decided to dig a little deeper.

The miter gauge is fixed in place by machine screws, I found that the machine screws capture only the sides of the slotted holes they fall into, and just barely do so at that. So easy solution was to just put washers under the machine screws and finally it seems to have worked. I had intended to purchase washer face screws, but Festool used 5.5mm screws, something I can't seem to source in the same variety as would be offered to more typical sizes.

https://brianholcombewoodworker.com/wp-content/uploads/2018/02/img_9331.jpg

I checked for squareness with a Matsui square, its precision beyond what is really needed for woodworking (according to some, not me). And at long last it reads square and remains that way.

[Nick Decker]

So, you're saying that squaring wasn't possible with the factory fence(s)?

[Brian Holcombe]

I could square it up but it would come out of adjustment quickly. The factory fence is pretty accurate as I found it, but I wanted to be able to square this to .001"~ and even the most minor detail can cause issues at that degree.

I am curing two problems in the above, the moving miter gauge (which causes out of square cuts) and wanting to make zero clearance. I cut a lot of small miters, and the off cut will take flight without a ZCI. Or as I had it previously with a ZCI on one side of the saw, which is much easier to line up but does not cure the flying small off cuts.

[John TenEyck]

One would expect better for double the price of most other saws.

John

[Brian Holcombe]

One would expect better for double the price of most other saws.

John

What really annoyed me was the bolt size, it's extremely difficult to find 5.5mm washer faced bolts. The bolt shoulder barely grabs the sides along the bolt hole and yet if you drill it out to cut threads for a large bolt then you need source a much larger bolt because of the way the tap sizes work out once you clear the current threads. Why they would not simply cut for a 6mm button head wide flange and have much more contact surface is beyond me.

I checked clearances, they have room for a larger bolt without interfering with any mechanisms.

[Martin Wasner]

I don't mean to be a on this, but it's an install saw. They aren't made for heavy cuts.

Yes, I know it's expensive compared to other similar saws, but it's about half the cost of a chop saw made to handle heavy work.

[Reinis Kanders]

At least it can be made square. I have Makita XSL06PT cordless miter saw and it has great features, but 90 degrees in sliding mode are very hard to achieve. I had to wrestle with the guide rails to adjust it to somewhat 90 across the whole sliding range. I am tempted to try Kapex, but seems that it has its own issues.

[Brian Holcombe]

I don't mean to be a on this, but it's an install saw. They aren't made for heavy cuts.

Yes, I know it's expensive compared to other similar saws, but it's about half the cost of a chop saw made to handle heavy work.

Doesnt offend me at all, and I agree but still I can’t help but want it to be accurate and stay that way.

[Phillip Mitchell]

It's not a good sign that a miter saw costing $1500 can't hold 90* consistently.

There are many reported motor failure issues with the Kapex as well (mostly from finish carpenters.) I hope yours fares better than some others I've heard about.

[John TenEyck]

Brian, could you install Helicoils so that you could use 6 mm (or other) bolts?

Is this saw for shop use only? If so, a RAS would offer everything you are after.

John

[Brian Holcombe]

John, I don’t do much field work but I’m not sure that I never will so I got this assuming I could straddle the line. I may attempt to get a sliding table saw down into that shop at some point.

I could definetly heli-coil, I just hate to do it. If the fence moves at all with this setup I will cut it and heli-coil.

[Brian Holcombe]

It's not a good sign that a miter saw costing $1500 can't hold 90* consistently.

There are many reported motor failure issues with the Kapex as well (mostly from finish carpenters.) I hope yours fares better than some others I've heard about.

Thank you, I wish it had a bit more power but I may experiment with other blades and see if it makes the chopping easier in hardwoods. I just take my time in heavier cuts and avoid bogging the saw which is hard on motors.

[Martin Wasner]

Have you looked for a used OMGA? They're pretty much indestructible. The first one I bought was 1ph and built in 1994 I think. For almost ten years it was my only cut off saw for face frame parts and door parts. It still cuts beautifully, though I'm pretty sure the bearings are starting to go. It's got the first hints of getting noisy.

[Brian Holcombe]

I have, but unfortunately they do not have the depth capacity I want crosscutting, I work with wide material very regularly and so the saw would see very little use at 6" capacity.

[glenn bradley]

One would expect better for double the price of most other saws.

John

It may be German and green but it's still just a chop saw. Precision is not as much of a design factor as with some other things.

[Martin Wasner]

I have, but unfortunately they do not have the depth capacity I want crosscutting, I work with wide material very regularly and so the saw would see very little use at 6" capacity.


That would be a problem.

[John Sincerbeaux]

Make those cuts on a German Slider and I promise you won’t be disappointed.

[Brian Holcombe]

Make those cuts on a German Slider and I promise you won’t be disappointed.

I wouldn’t be disappointed by a Patek Philippe Grand Complications either. 😁

[John Sincerbeaux]

You have fine taste😀

[Brian Holcombe]

Haha, indeed. However, the budget has some serious catching up to do. 😩

[Sam Beagle]

I’ve found my Kapex to be dead on. And I carry mine around in my van a lot. Very costly. But I’m always confident with every cut I make using it

[Robert LaPlaca]

I have a Kapex, one thing for sure one couldn’t fine a better small piece rocket launcher, I mean jeez sometimes the thing scares the crap out of me. I had a old DeWalt compound miter saw that maybe launched a dozen small offcuts in 15 years, this thing had that beat in the first week of use. Going to have to try the subfence trick to see if it cures the beast..

[Patrick Walsh]

Holly smokes Brian I had to google Patek Phillipe Grand. Normally I also am in the know with regard to such extravagance. This one thought I missed the bus....

I couldn’t help but think “really” why would anyone spend so much on a watch. Then I heard the voices of my shop mates handing out to me for my most recent aqusition of a Martin t-20 shaper. Their perspective is “the boss barely has 20k into his whole shop separate from a brand new SCMI widebelt sander” they think I’m nuts.

I have to remind them each to his own and most of us spend on something. Some it’s cars, other clothes, vacations eating out. Others choose to raise a family “a costly affair” but that is also a choice..

I have a love hate with my kapex. I shared pictures of our chop saw station at work. That thing is well words I can’t use on a public forum. I also would like to go Omga fir face frame and small material then slider for larger stock.

At work I have for the most part resorted to using the slider for all cross cutting when I need square repeatable pieces. I do get shot from my shop mates as the wood burns and dulls the blade on the saw. Can’t make everyone happy is what I say...

[Brian Holcombe]

Congrats on the T-20! Exactly, we’re all basically choosing which extravagance we prefer. At least these can earn a return for us.

It would be fantastic to have room for multiple options. As much as I complain about the Kapex I think it’s a great tool, but just likely a bit under-kill for my want.

Whenever you’vr Worked with serious tools it truly ruins you for even good lightweight tools. For instance the machine shop I worked at had a huge polish made lathe, this thing was sturdy beyond sturdy and beautifully made. Every lathe I’ve seen after that, including the one I just bought, has been like a kid’s toy by comparison.

[Bill Adamsen]

Following with interest. I am still using a Hitachi 8" slide I purchased new some 25+ years ago. It is a good enough tool though it has lousy DC and I'd love an upgrade. For that reason I have considered the Festool. But the Hitachi is much like driving a car with 300k+ miles ... it has become so idiosyncratic that while I am the only one that can "drive it" I drive it reasonable well. My sense is that you have solved the problem and that is the goal for which I typically shoot. One thing I keep watching is the "quiver" of Festool saws available overseas but not in the US. I'm assuming there are other quality cutoff tools of this ilk simply not available in the US. Are we missing an obvious solution?

[Dave Sabo]

I may be alone and incorrect in this , but , is there a woodworking miter saw accurate to one one thousandth of an inch ?

Consistently ?

And , are you sure that the wood you cut isn't going to move naturally by .001" after you cut in but before you glue it up ?

Really ?


And wait til that saw's motor burns up, then you're really going to be smitten with it. Or find out your blade sharpener can't deal with the variable spaced teeth. After they've ruined your blade.

[Brian Holcombe]

I may be alone and incorrect in this , but , is there a woodworking miter saw accurate to one one thousandth of an inch ?

Consistently ?

And , are you sure that the wood you cut isn't going to move naturally by .001" after you cut in but before you glue it up ?

Really ?


And wait til that saw's motor burns up, then you're really going to be smitten with it. Or find out your blade sharpener can't deal with the variable spaced teeth. After they've ruined your blade.

I can't imagine that many chop saws are that accurate, their is a reasonable tolerance for how well something *should* be assembled from a factory. However, it's pretty easy to square something to less than .001" if you have an accurate square and a slight amount of patience. I use a matsui square and square the blade until I can see no light pass between it and the squares edge. After I do that, it's the job of the saw to retain the position of the blade.

With one machine you're no longer dealing with tolerance, you're dealing with error. Minimizing error to a very small degree is possible and hardly more difficult to leaving it less accurate as long as your checking tools are accurate.

Finally, I cut wood and checked the cut for squareness.

Do you not setup your tools after you receive them?

WRT your second comment. I see this comment very regularly made as an excuse to ignore the accuracy of your setup. Wood moves, yes, what does that have to do with how square you'd like to cut something? Wood doesn't move along it's length to any significance, so unless it swells or shrinks in a bell shape then the cut will remain square. Further, most often we're squaring something because we'd like two edges parallel to one another in order to reference additional work or for accurate assembly.

Not sure what to do with the last bit of your post, it seems very flippant.

[Brian Holcombe]

Following with interest. I am still using a Hitachi 8" slide I purchased new some 25+ years ago. It is a good enough tool though it has lousy DC and I'd love an upgrade. For that reason I have considered the Festool. But the Hitachi is much like driving a car with 300k+ miles ... it has become so idiosyncratic that while I am the only one that can "drive it" I drive it reasonable well. My sense is that you have solved the problem and that is the goal for which I typically shoot. One thing I keep watching is the "quiver" of Festool saws available overseas but not in the US. I'm assuming there are other quality cutoff tools of this ilk simply not available in the US. Are we missing an obvious solution?

I think they have a lot of stuff available in Europe that is more directly competitive with timber framing type tools.

[Patrick Walsh]

Brian you said flippant lol...

Oh boy there’s my meat head former sight carpenter slipping out again...

[John Petsche]

Great tip using washers, thanks!

[Brian Holcombe]

Thank you!

[Van Huskey]

I wouldn’t be disappointed by a Patek Philippe Grand Complications either. 

This thread in conjunction with the mortiser thread makes me think you could start a machine modification business. Sort of a Ruf Automobile for Euro tools.



I can think of one time every 5-7 years or so a PP GC would disappoint... service time. My pedestrian by comparison 5980 came back after 7 months with a 1.5 Kapex bill. I think a GC is in the 5 Kapex range.

[John Gornall]

Brian, are these miters you cut 45's
If so look at picture framers saws - My saw is fixed at 45 degrees, 2 motors, 2 blades, all steel, no aluminium, doesn't need adjustment. I step on a pedal and both blades come down. The fence is towards the operator and the outside of the teeth just pass the fence so the teeth are cutting down against the table - no flying pieces. A standard chop saw is meant for carpenters - in fact when the blade first touches a 2x4 the teeth are cutting up - it's a compromise to increase capacity.

[Jebediah Eckert]

Brian-

Any chance you could snap a pic of where / how you placed the washers? I don’t think I follow what you did.

Thanks

[Pat Barry]

Brian-

Any chance you could snap a pic of where / how you placed the washers? I don’t think I follow what you did.

Thanks

+1. Which screws needed the washers? Are they shown in your posted picture?

[Dan Friedrichs]

+1. Which screws needed the washers? Are they shown in your posted picture?
+2. Was about to ask the same thing :)

[Mike Cutler]

Coming into this thread late, but if anyone needs to source metric fasteners, like the 5.5mm Brian did, go to a high end bicycle shop. 5.5mm screws, while not common, are also not uncommon on european bicycle frames. American spec'd frames made in Asia, with primarily Shimano Gruppo's, will have 4,4.5, and 6mm fasteners. The European made frames and Campagnolo Gruppo's are different standards.
One other option is to get rid of the 5.5mm, fill the hole, and tap it out to 6mm or even 8mm.

PS
Just be glad this isn't the 50's. There were three metric standards back then. Italian, French and British and three different pitches of 5.5mm fasteners to chose from. :eek:

[Brian Holcombe]

These are for the bolts that hold down the plate with angle markings on it, the machine used that plate’s detents to set it square.

Replacing with 6mm would be ok, but larger than that won’t work, the assembly that passes over the plate doesn’t offer enough clearance.

I have a bike shop in town, so I’ll check them out for a sexier bolt. Ideal to me is typically a washer faced bolt with sized washer under it.

[Art Mann]

Something about your statement below doesn't make sense. You mention a linear dimensional error (.001") and yet you are talking about an angular error. Which is it? How are you doing your measurements? Over what distance is that error? How did you make the measurement? Is it repeatable? Are you saying you can use a miter saw to trim off a piece of wood and then expect it to be the same thickness within 0.001" every time?


The factory fence is pretty accurate as I found it, but I wanted to be able to square this to .001"~ and even the most minor detail can cause issues at that degree.

[Brian Holcombe]

My aim is for the saw to cut squarely.

The mark ~ means approximately, so the intention of the statement is to suggest I'm aiming for the smallest possible error within the setting of my miter saw, not that I will set it to .001" without demonstrable error. Goals and results are two different things.

In this case it easiest to check squareness with a known square item (certified precision square) over a practical distance. The error in that distance should be minimized. The distance used was the length of the cut capacity of the saw. The error was checked in the dynamic rather than static as it matters only that the saw can make a square cut.

The saw is not actually sturdy enough to cut without some error and I believe the error is greater than .001" but I did not check it since the error was equal over the distance of the cut (it creates a very slightly curved shape over the length of the cut).

[Dan Friedrichs]

Brian, I don't have a Kapex, but appreciate this post, nonetheless, as it has got me thinking about solutions for the slop in my cheapo miter saw. It hadn't occurred to me that the miter gauge detents, and therefore, the miter gauge connection to the saw body, is what defines the squareness (assuming a flat fence). Thanks!

[Brian Holcombe]

Thank you, Dan! Glad you are finding this to be thought provoking.

[Patrick Kane]

i had a used kapex for a few months and sold it for a profit afterwards. Didnt care much for the handle, and Brian is right, squaring it up and maintaining that setting is a fool's errand. Granted, i was using mine to cut .75-1.5" thick hardwood. Secondly, adjusting the parallelism of the lasers was like putting a man on the moon. I eventually gave up on that endeavor and went back to lining cuts up to the blade. In order to do that, you need to "modify" the guard. I remember it locking into place until you turned the saw on. The bevel adjustment was very nice, and i can see if you cut MDF trim on site all day why you might like this saw. In a home shop setting, i dont think it has much of a place. Almost to the day, a year ago i sold the kapex and a tricked out jessem router table that paid for almost half of my Felder KF700. The jessem router table was really nice, but its still just a 12-15amp router motor with an MDF surface and some aluminum bits thrown in for good measure. That is kinda how i view the kapex, a clever tool that went way too far down the road of diminishing returns. Actually, thinking back on it more, i sold my MFT-3 on top of the others, and that paid for more than half the Felder. If you were buying new, which i wasnt, by the time you bought the $1475 kapex, $1500 jessem package, and the $700 MFT-3, you are very well within striking distance of a used euro machine that will do all of those tasks to a higher degree of precision and with more efficiency and dependability. Identical argument to the previously mentioned OMGA.

[Brian Holcombe]

I agree completely, it works for the moment. I need a larger space before I can consider much more machinery,

[John Petsche]

Thanks for the great tip.

[Randy Heinemann]

Brian,

Maybe I missed something (didn't read this thread till today because I couldn't believe it was still live with posts) . . . Are you still having the same problems with the Kapex? If so, I would have long ago sent it to Festool for warranty repair (if I didn't miss the post where you already said you did that).

I have only used a Kapex in a couple of the Festool classes at the Festool HQ in Lebanon, but, I have to say, the cut was dead on square repeatedly over a number of cuts made for the projects done in class. I would have bought one for sure, given the various features I felt were important, but I feel a miter saw is useful for what I mostly do. I previously owned a Hitachi and, while relatively accurate, dust collection was bad and I found the space it took wasn't justified for me. So, buying a Kapex didn't make sense. Instead, I embarked on my Festool purchases with a track saw and MFT, which I find very accurate and precise and it serves almost all of my needs.

However, I would say that, if you are still having problems and the saw is still under warranty, get warranty service. There is no reason I know, based on my limited experience that this saw should not be able to repeatedly cut accurately and square, with or without an auxiliary fence (assuming the auxiliary fence has not introduced some inaccuracies).

Sorry if you have already made contact with Festool Service and they didn't help you to your satisfaction. However, I would agree that, at Festool's prices and their claims of high quality, accurate tools, that you should be able to get an accurate, precise saw that cuts square repeatedly. You should keep after them until they fix whatever the problem is.

[Brian Holcombe]

It cuts square now. The service department basically they said it was an issue with the saw that was unsolvable by them. I solved it.