DeWalt T-Square not Square out of the Box

[Dave Ronyak]

Recently I purchased a DeWalt T-Square attachment for Guide Rails, and a pair of DeWalt's "quick clamps" for securing a Guide Rail.  Both DeWalt products fit Festool's Guide Rails.  The clamps also fit the channels in the side rails of Festool's MFTs but not the holes in the MFT tops.  I thought these might be handy when working at a jobsite without my MFT for cross cutting boards, panels and sheet goods.

Shown in the photos below is the packages for these products.

Here is the T-Square attachment itself.  Note the short piece of metal with the two black screws.  That component is a dovetailed key, raised above the surrounding top surface of the housing.  It should be exactly 90 degrees to the machined face of the housing.  Mine was not.

Here is the DeWalt T-Square partially mounted on my LR 32 Guide Rail.

I checked its fitment to all of my Guide Rails and found it to be a tight slip fit on most, most loose on this LR 32 and the 1080mm Guide Rail mounted on my  MFT 1080.

Here's the view from the underside, with the DeWalt T-Square fully mounted on my LR 32 Guide Rail.  The black knob is used to secure the T-Square in position.  When tightened, the dovetailed metal protrusion is wedged within the channel of the Guide Rail.  This simple clamp system works well.

All appeared well until I checked this assembly for squareness against a pencil line drawn with my 18" Precision Carpenters Triangle.  The plywood panel shown in the photo has straight edges that were cut with my TS 55 on a Guide Rail.  There was about 1/32 error across the 12 inch width of the panel.  I rechecked this several times.  OK for some work, but less than my goal.  I repeated this check with 3 other Guide Rails, all came out the same deviation and in the same direction.

I fixed the error by disassembling the T-Square and judiciously filing the sides of the metal piece that has the dovetailed key that grips the Guide Rail channel.  I did not remove any material from the dovetailed key.  I removed material from the base of the key so it could be slightly rotated within the recess molded into the body of the T-Square.  This required several iterations, including slightly reaming out the screw holes that attach this dovetail key to the housing of the T-Square.

The result was no discernible deviation from the 90 degree pencil line drawn with my precision triangle square.

Dave R.

 

[GreenGA]

Well, that's another fine mess you got us out of Ollie, er... Dave...

You found and corrected a problem with this T-square and I believe it was you that found and corrected a problem with the Domino.  Both "repairs" required some hand-reworking or filing of the cast materials or something along those lines.  May I make a suggestion?  I know, I know, I've been down this road before...  :

Would you mind some photos of the repairs in progress?  You know, for the rest of us?  Those that are loath to disassemble something like a Domino because we're not certain we will get it back together again. (hey hon... do you remember where does this little thingie goes in the Domino...?  ??? )

I know I would approach such a "repair" with trepidation even knowing the outcome may make my Festool even that much better.

JMTC

And keep up the good work.

Happy New Years to All...!!!

 

[Dave Ronyak]

JMTC,

It wasn't me regarding the Domino.  My unit came well lined up.

Sorry for the lack of "in progress" photos, and for the poor quality of my photos - my cheapo Radio Shack camera has no ability to manually adjust the focal length.

You may need a slide hammer puller to disassemble the key from the housing.  I removed the black knob and the two screws that secure the key, then inserted a pan head screw into the key from the (top) side on which the black screw were inserted.  I placed this assemble on the floor and lightly slapped the slide hammer weight upward to pop the key out of the housing.  The slide hammer I am referring to is of the type used to remove automotive axles and press fitted bearings.

Dave R.

 

[sw1211]

Well, that's another fine mess you got us out of Ollie, er... Dave...

You found and corrected a problem with this T-square and I believe it was you that found and corrected a problem with the Domino.  Both "repairs" required some hand-reworking or filing of the cast materials or something along those lines.  May I make a suggestion?  I know, I know, I've been down this road before...  :

Would you mind some photos of the repairs in progress?  You know, for the rest of us?  Those that are loath to disassemble something like a Domino because we're not certain we will get it back together again. (hey hon... do you remember where does this little thingie goes in the Domino...?  ??? )

I know I would approach such a "repair" with trepidation even knowing the outcome may make my Festool even that much better.

JMTC

And keep up the good work.

Happy New Years to All...!!!

JMTC, I still maintain if you have a Domino that needs that type of repair work, return it (assuming it's under warranty) and get a new one.  Festool used to say they wanted to see Dominos that have problems, pre-tinkering, so they can improve their product.  If you have a tool with a problem that can be returned and get a brand new one, or have them repair it, why wouldn't you do that?  Last thing I want to do is start filing down a $750 tool, oops too much off there, not enough there, talk about a slippery slope.  Reminds me of the ONE time I tried cutting my toddlers hair, take a little off here, oops now more off here, now the other side needs more, wife made it clear never to touch his hair again.  Now if the Flobee could be hooked up to a CT we might be on to something.

 

[fshanno]

Interesting.  Mine is dead on at 24".  Are you comfortable that your fix is going to hold?  Does it depend on how tight the screws are?

 

[Peterm]

It's irritating when things aren't bang-on right out of the box - mine was a little out-of-true when I got it as well; my slightly less-technical-than-yours fix was a couple of strips of masking tape stuck on the edge of the T that needed packing out. Works pretty well, now...

Cheers, Pete

 

[honeydoman]

your biggest mistake..... was buying dewalt.  sorry, but thats they way I fell.  most of the dewalt tools I bought when I started would fall apart day one.  had a drill that the whole chuck was left in the wall when I pulled the drill out.. 1 day old..... my table saw keeps having things break off etc.  on and on.  no tools are 100% top of the line but dewalt is at the bottom of the list.  I even thank roybi is better.

 

[thender]

A 1/32 error over 12 inches is about on quarter of a degree. 

To me, the Achilles heel of the tee-square approach is that the channels in the guide rail aren't a precision-ground surface;  instead they are unfinished extrusion. 

That groove in the underside was primarily intended for clamps, not aligning the cutting edge.  So it may not have been fabricated with exacting tolerances.

So we should expect some variation from location to location and from guide to guide. 

So it isn't obvious to me if the error was the tee-square fitting, or the guide rail.  If you try it on different rails, and at different locations on the same rail, you may get slightly different results. 

So with tee-squares, as in Strategic Arms Limitations, we should all "Trust, but verify" when making a cut that needs to be very precise.

This has been a good post -- thanks to the OP and al that replied.

-T

 

[Dave Ronyak]

Interesting.  Mine is dead on at 24".  Are you comfortable that your fix is going to hold?  Does it depend on how tight the screws are?

FSHanno,

Good questions.  Consider yourself fortunate.  Only time and use will tell.  The part I modified is trapped in a recess in the head as well as attached by two screws.  Even after my judicious filing away of some metal, that key still is somewhat wedged upon insertion into the head.  I'll continue to rely on my 18" precision carpenter's triangle when I need absolute 90 degrees.

Tom,  I did try it on four different Festool Guide Rails and at different positions along them, all with the same results.  That is when I decided my DeWalt T-Square was not square.

Dave R.

 

[nickao]

Dave why didn't you return it and try a second one? Maybe it was just a lemon.

 

[fshanno]

I guess I was lucky.  I've dedicated a 55" guide to it for crosscutting and it's turning into a real workhorse for me.  I'm going to take the caution about DeWalt stuff under advisement,  but so far so good.

I too was concerned about the channel in the guide.  I put quite a bit of stress on the thing when I'm sliding it up to the mark, working against the friction between the guide and the surface.  I press pretty hard against it to make sure it's touching the reference edge.  I don't think that Festool has anything quite like that in practice.  Only time will tell I guess.  Dedicating a guide to it so there are no on and off cycles may help a little. 

 

[Dave Ronyak]

Dave why didn't you return it and try a second one? Maybe it was just a lemon.

Dogged determination?  Stupidity?  Avoiding more hassle and possibly greater expenditure of my time? 

I did not return it for another because that would likely have cost me more time and money than fixing the one I have, and who knows if the next unit would be any closer to true 90.  I'd have to drive 66 miles round trip to the nearest Woodcraft store from which I ordered the original unit because they had none in stock.  If I called them to get a replacement, I'd have to wait for that one and hope that it was true 90, and repackage and send back the old one, etc.  If the local Woodcraft store stocked this T-square, then I would have taken one of my Guide Rails and precision square and tested the replacement to ensure it was true 90 before leaving the store.  It was simple to improve the one I already have. 

Dave R.

 

[nickao]

Yes that's a hassle.

I only order off the net, its just to convenient for me.