high tolerance square cutting on MFT3 -?

[panelchat]

thanks again guys for all the good info here- i bought the thing and will be hacking up some dead tree soon. looking forward to using it. the grid hole system is particularly interesting..

 

[Kevin Stricker]

Anyone who says they can get panel saw repeatable accuracy with a stock MFT3 is either delusional or has very poor eye site.  Yes you can get square cuts, but not to the tolerances you are looking to achieve. 

Building a single square cabinet or entertainment center, no problem.  Building a 40 box kitchen, you had better adjust your expectations and use building methods that allow for some variability.

Just to let you know, your expectations exceed industry standards by a large margin.

 

[RONWEN]

greg- thanks, yes that's a typo! and a micrometer or dial caliper measures a hair at about .003"- far bigger than .0004" [blink]
and yes, you quickly run up to the limitations of a tape measure, kinda have to carefully wing it.. at best..

it would be nice if the system had stated tolerances like some other precision products.

part of my concern in all this is that my second TS55, that I use now, came with a bent rail. I found out the hard way, but it was replaced without much fuss.
also- I just spent many hours sorting out a blade to shoe square problem- turned out the blade was square, but the toe in was set at around .75mm out. waaaay too far. apparently from the factory, as the saw has never been dropped/banged. this was leaving panel edges a degree or two off 90, fouling up any tight work i was doing.

a lot of time was lost troubleshooting and dealing with the above two items. the upside is you get to know the tools better...

it sounds as if you set up the MFT3 correctly, in the right sequence, and use that delrin thingy in the rail channel, the system can deliver on being a "portable panel saw"

Even an expectation of +/-.003" is well beyond necessary when working with wood cabinets & furniture.  The wood itself  will have seasonal changes of ~10 times that.  If you'll target yourself to working to say 1/64" (.016") or 1/2mm (.020") you won't disappoint yourself or anyone else.
As others have said, the MFT isn't a high production tool but it certainly can be adjusted to provide those looser tolerances on a fairly repeatable basis.
If you are a perfectionist and are only happy when things are "dead nuts" I would suggest cutting your pieces proud by something like .010" and then bringing them to finish size with a shooting board & bench plane which can easily trim pieces ~.0002" per pass.

 

[panelchat]

yes, im not interested in unnecessary machining tolerances/accuracies here, i usually use a 64th as good enough for panel cutting. but better than that is very helpful for making euro box kitchens. was just interested in whether or not the MFT could approach the accuracy/repeatability (not speed/volume) of a 15,000 free standing machine.

as someone who has basically been in small shops for years, a super square/accurate/cheap/safe track based system would be like a holy grail of small shop niche products. Started using the MFT yesterday, we'll see how she runs... It really seems like an open platform for endless tricks/modifications...

 

[ccarrolladams]

Well, panelchat, I have yet to find a panel saw costing in the USA$15,000 range that will repeat to the accuracy you want.

In my large metal fabrication facility all of our CNC are calibrated to repeat to 0.005mm. That may or may not be needed when working aluminum, but can be important when working with stainless and tool steel.

The 5' x 12' Holzma CNC pressure beam saws I use to cut 95% of my custom cabinet sheet material parts are calibrated and guaranteed to repeat to an accuracy of 0.1mm. I have seen people using the same saws without the scoring unit and with spray coolant cutting thin tool steel plate to such accuracy.

My beam saws have only been used for plywood and occasional sheets of MDF, MDO and HDF. I am confident at the moment the sheet material is cut it is that accurate. However, plywood is a live product, so it changes dimension with time.

To ensure the very best fit during assembly of cabinet cases, we only cut the parts we can assemble within the next 4 hours. Our building is fairly well climate controlled. But to be sure we can make the parts fast enough, we have two identical beam saws.

My similar size CNC routers also position to better than 0.1mm, but again, even plywood is live enough it swells and shrinks. At least, when the sawing and routing is performed to these accuracies, a given part will swell and shrink together.

We own a large Felder CNC sliding table panel saw that we use mainly for working solid lumber.

Generally when we make odd angle sheet-good parts, we do so with TS55s, guide rails and a protractor cross-cut fence from a sliding table saw. Using this approach our accuracy is as good as on a CNC machine. It takes slightly longer, but while the CNC machines have an overhead charge of USA$300 per hour, our guide rail, protractor and TS55 system has no significant overhead and only the cost of a single cabinet maker. Therefore we can afford to go slower making the odd angle parts our way.

Besides, all of us are cabinet makers. We really enjoy proving we still can use marking knives and guide rails, pushing the saw manually through the wood. None of us feel as much "At One with The Wood" using a CNC machine.