kapex reb 120 BASE NOT FLAT AND FENCE NOT SQUARE

[Packard]

My  experience is with injection molding and iron castings, but I think it will extend to the aluminum castings.  With both iron castings and plastic molding, the molten metal/plastic has to remain in the mold for a certain amount of time before being released.  If the components are released from the mold too early they will either warp, or in the case of plastics, they might shrink and or warp. 

So why would a company release the parts before they are fully set?  Because a faster cycle rate means more income.  You have to remember that the castings are rarely done in-house.  They are being done by a subcontractor.  So the finished product is not as important to the vendor as it is to the manufacturer. 

So if the castings are warped, maybe Festool has to find a better vendor or maybe the Festool purchasing agent insisted on too low a price and the only way the vendor could reach that price level was to shorten the casting cycle. 

If it is a persistent problem, then it is a process problem.  Festool needs to examine their process.  Of course Festool might not consider this a problem at all.  Perhaps these saws are all within prescribed tolerances.  It would be interesting to find out what the flatness tolerance for these machines is. 

Has anyone asked Festool that question?

 

[jimbo51]

I seem to remember someone asked Festool about the tolerances on the guide rails a few years ago. I think they are still waiting for the answer. I assume asking about Kapex tolerances might get the same reply.

 

[Birdhunter]

With cast iron, doesn’t the foundry “age” the castings before they are machined? I’m thinking about my SawStop ICS. I’ve read that the castings “move” after they are taken from the mold.

 

[Packard]

The best way to stress-relieve a casting is to very slowly (over a period of 7 to 10 days for large castings) lower the temperature to the ambient temperature. But that is very costly and is rarely done anymore.

A cheaper substitute is to attach with a magnet, a high-frequency vibrator.  It is supposed to work nearly as well.  I am less familiar with smaller castings, but I believe they still stress relieve the parts in a large oven.

I bought a new Subaru in 1971 or 1972--before It was being imported by Subaru, but rather by a distributor in upstate New York.

After 3 or 4 weeks my front rotors would warp.  The dealer would cut the rotors under warranty.  They would warp again in 3 - 4 weeks. 

I probably had 8 or more sets of front rotors in the 12 months I owned the car.  I sold the car at 12 months when the warranty ran out.  Eight sets of rotors would have cost be $2,000.00 (in 2021 dollars = $13,718.74).  Each rotor was $125.00 back then.  There were no Chinese-made replacement parts.

Those rotors failed because they were not properly stress-relieved after casting. 

Warping from internal stresses occurs when something is done to the casting.  In this case, I suspect the final machining caused the subsequent warping.  I blame the castings in the unfinished condition.  I am pretty sure that the CNC machining was done accurately.  The loss of flatness happened after the machining.

 

[Cheese]

With cast iron, doesn’t the foundry “age” the castings before they are machined? I’m thinking about my SawStop ICS. I’ve read that the castings “move” after they are taken from the mold.

Years ago, lathe manufacturers used to age or season their lathe castings in unheated portions of the factory or sometimes they just tossed them outside for a year at a time. The extended thermal cycling was supposed to be the cure and there were some adherents that promoted that the rusting process also helped the stabilization process by reducing the toughness of the skin coat on cast iron and thus reducing surface stresses.

Here's a photo of 1000 Atlas lathe beds aging in 1933 and South Bend lathe castings aging in 1925. I find the difference in aging techniques interesting. The South Bend items are all arranged in neat, readily reachable rows and stickered like lumber while the Atlas castings are just placed in unmanageable piles, tough to apply FIFO with the Atlas system.  [huh]

[attachimg=1]

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At sometime, it then became cheaper/faster to thermal cycle these castings in furnaces and cold boxes.  Nowadays, cryogenics has taken over from the furnaces but there are some that say that cryogenic cycling is not a substitute for thermal cycling. The debate continues.  [smile]

I do know 30 years ago I was having warping issues when machining PTFE/PFA/FEP (all different forms of Teflon) valve bodies. I located a cryogenic firm out in Washington state and sent them 60 valve bodies to treat. After receiving the valve bodies and using best standard machining techniques, all machined up 5X to 6X better than before the cryogenic treatment.

 

[Packard]

I find it difficult to believe that the Kapex components left the machine shop with the warp in it.  I cannot picture how a milling machine could accommodate that warp.  So it is likely that the internal stresses created during the casting process caused the warping after it left the machine shop.

I would still be interested in what Festool publishes as a flatness tolerance. 

I would expect Festool to call out the flatness standard something like this:  Maximum out of flatness of ± 0.015" over the span of the surface.

In any case they have to have a manufacturing specification.  There is no possible way they could schedule production without a called out tolerance.  Otherwise the Quality Assurance department would not be able to do their job. 

Of course, Festool might decide it is not in their best interst to reveal that tolerance.  In which case we can complain here. 

 

[ChuckM]

I would still be interested in what Festool publishes as a flatness tolerance. 

It doesn't exist in the public domain as far as I know. I wonder if any other miter saw manufacturers have provided such info. as part of their product specifications.

 

[Packard]

I wouldn't think that they would publish it, but if you wrote to them and said, "My Kapex base is 0.015" out of flat.  What is your specified tolerance for this part?" I would expect to hear back either with the actual tolerance or with a reply that said, "Your base is in/out of tolerance".

 

[Packard]

When I was 13 or 14 back in 1961-1962, I had a go-kart with a McCulloch chain saw engine.  When the head gasket blew I "machined" the head by gluing some emory paper to a piece of plate glass and rubbing the head against the now-flat sand paper.  After a few minutes of rubbing the head was flat as I could see all the surface had a uniform finish. 

But then I decided to increase the compression ration by "machining" off more of the head.  I went at it for about 15 minutes and then declared that it was "machined".  I was convinced that the results were better than before the modification. 

I had no measuring tools so I had no way of measuring how much material I took off.  I also did not know the formula for figuring out the new compression ratio.  I also did not know the original compression ratio. 

But the glue-the-paper-to-the-glass trick worked.  The glass apparently was quite flat.  The engine ran fine until I crashed the cart a year later and I then gave up on the hobby.

I expect it would work just as well on a Kapex.  But you didn't hear it from me if it totally messes up your saw. [eek]

 

[AlexThePalex]

Of course, Festool might decide it is not in their best interst to reveal that tolerance.  In which case we can complain here.

Indeed, they have decided not to reveal that tolerance. Somehow that's the way of big companies.

But they're the only big company that gave you a place to complain, and that is somehow very uncharacteristic for a big company.

Someone here said other companies can make flat saws. No, they can't. Not within the tolerance specs of this price point. But they just don't give you an opportunity to publicly complain about it.

 

[ChuckM]

Someone here said other companies can make flat saws. No, they can't. Not within the tolerance specs of this price point. But they just don't give you an opportunity to publicly complain about it.

I had never thought of checking the flatness of my Kapex until someone (in an older thread) brought it up. Nor did I check the previous miter saws I owned. In fact, I still haven't checked how flat my SawStop or bandsaw table is, since I've been happy with the results of the cuts. One thing that I do check when bought new as well as from time to time is the group of squares.

But FOG is not the only opportunity that people can voice their findings and opinions on Festool products or any other brands. There're at least three to four other forums -- some with more active participation, some less than FOG -- in which any woodworker can join and make "complaints" about any tools and brands. There're also YouTube reviews or Instagram posts that woodworkers do use to express their views on brands and tools.

 

[AlexThePalex]

But FOG is not the only opportunity that people can voice their findings and opinions on Festool products or any other brands. There're at least three to four other forums -- some with more active participation, some less than FOG -- in which any woodworker can join and make "complaints" about any tools and brands. There're also YouTube reviews or Instagram posts that woodworkers do use to express their views on brands and tools.

Any of those forums run by the brand itself?

 

[usernumber1]

i'm not seeing anyone complaining that they are unable to cut their pieces to spec. or is anyone having issues with their miters?
just a lot of measurements of the machine itself

i'm sure festool will fix things if you have issues or 'until you're happy'. that's a good spec right there

 

[ChuckM]

But FOG is not the only opportunity that people can voice their findings and opinions on Festool products or any other brands. There're at least three to four other forums -- some with more active participation, some less than FOG -- in which any woodworker can join and make "complaints" about any tools and brands. There're also YouTube reviews or Instagram posts that woodworkers do use to express their views on brands and tools.

Any of those forums run by the brand itself?

I'm referring to opportunities, not ownership.

 

[jeh]

"...more quality control."

The head of Festool QA should pay a visit to the QA office of SawStop (if that has not already been done). She or he may learn a thing or two from them. I have had hands-on experience with or spoken to owners of 4 ICS, 5 PCS (including mine), 2 Contractor & 2 Jobsite (older version) SawStop saws. Zero complaints about their saws from Day 1.

How do they do that? The machines (up to 600 - 700 lbs (/)) are made in Taiwan, and shipped to this part of the world. How could they achieve and maintain the factory settings to spec. and most important, to the satisfaction of their customers? What QC process do they use? What equipment or test cuts (if any) do they put in place to be so successful? How about their sourcing of parts and metal? What kind of control do they have over their production partners, or assurance from them? What kind of people do they hire and train to be the gatekeepers? The fact-finding trip might not be possible before, but SawStop is now part of their family.

Comparing the flatness of a cast iron top to that of a mitre saw is a worthless comparison. They are not even remotely similar in construction.

 

[ChuckM]

I think you missed the point. It's not about the flatness or the Kapex.

 

[edwarmr]

But the glue-the-paper-to-the-glass trick worked.  The glass apparently was quite flat.  The engine ran fine until I crashed the cart a year later and I then gave up on the hobby.

I expect it would work just as well on a Kapex.  But you didn't hear it from me if it totally messes up your saw. [eek]

I thought about this a lot after watching that video in the initial post as well as another video about flattening a miter saw on youtube.

Here’s the problem as I see it, please correct me if my thinking is wrong. Flattening a miter saw including the Kapex should work great IF… the turn table rotates on an axis parallel to the extension wings. If the axis of rotation is off at all then flattening with sandpaper will not solve the problem. It would make your saw perfectly flat if you leave it at the angle it was at when you flattened it. But as soon as you rotated it to another miter angle the benefits of flattening it are essentially gone.

I made these drawings to try to illustrate what I’m talking about (sorry they are very poorly done  [unsure]). I exaggerated the problem so it would make more sense visually. Hopefully these pictures illustrate what I’m trying to describe. This would be looking at the Kapex from the side. I realize a Kapex or any miter saw can’t rotate even close to 180° but I just did that in the picture to exaggerate what happens when rotating the saw after flattening with sandpaper if your turntable is not rotating parallel to the extension wings. Notice that once the miter angle is changed the turn table is no longer level with the extension wings.

[attachimg=1][attachimg=2][attachimg=3]

 

[edwarmr]

With my Kapex I believe the axis the turn table rotates on is tilted like in the drawing I posted but way less severely. I believe it is because my casting is warped and not because the turntable is a different height than the extension wings. This explains why when I put downward pressure near the locking handle on my Kapex it becomes nearly dead flat. If I had my Kapex bolted to a bench instead of on the UG stand I’m using I wonder if that would solve things?

In reality though I haven’t had issues with my Kapex for what I’m using it for. I like it a lot. If I was cutting tall baseboard regularly I could see how it would be an issue though.

 

[jimbo51]

i'm sure festool will fix things if you have issues or 'until you're happy'. that's a good spec right there

The Kapex motor issues took a long time to fix and many people were not happy for years.

 

[Cheese]

I wouldn't think that they would publish it, but if you wrote to them and said, "My Kapex base is 0.015" out of flat.  What is your specified tolerance for this part?" I would expect to hear back either with the actual tolerance or with a reply that said, "Your base is in/out of tolerance".

I'll put money on the fact that you'll not hear either of those responses from Festool...what you will hear is "Please send in the saw to our service department and make sure to include the completed repair request".
https://www.festoolusa.com/campaigns/microsites/onlinerepair

One of the issues for Festool is that they have no way to determine a customer's measuring capabilities with precision tools. Does this customer have a precision tool and does he/she know how to properly use it? So rather than proceeding down that rabbit hole, it's a lot more efficacious for both Festool & the customer to just send in the item for service. The few items I've sent in to Festool I've received back from them within 4-5 days. Their turn-around time is 48 hours.

It could be interesting though to send in a Kapex that is say .010" out of flat and if after servicing you measure it again and it is still .010" out, then inherent to that process, Festool's saying that .010" is within spec.  [smile]