# T-Track pressure limit before busted pull out?



## Holbs (Nov 4, 2012)

I am about to start a project on building a mortise jig. 3-4 days on SketchUp after looking over other LJ mortise jigs and such, I will be using 2 T-Tracks for stop blocks and sliding the front apron up and down. The stop block T-Track will be screwed into 1/2" of hardwood (yet to be determined what species). The sliding apron up and down on the front will be fitted in 3/4" plywood, which leaves just 1/4" of material to screw into. The sliding apron will have clamps to give enough pressure to hold tight the 2×4 (for example, toggle clamps). I am concerned… is 1/4" plywood enough "umfffff" to use T-Track and clamps? I see other jigs being AOK with 1/4" and T-Tracks.


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## TheFridge (May 1, 2014)

Check out woodgears.ca. Some great wood machine ideas plans and such.


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## Holbs (Nov 4, 2012)

woodgears.ca was a big reason to lead me into wood working  I love his engineering approach, though his mathematics sure goes go down a rabbit hole for me, at times.


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## RogerInColorado (Jan 18, 2013)

I'd be more comfortable with another 1/4 inch or so. Not a lot of margin for error if you hit a worm hole or something else you can't see when you are starting with really short screws. If your T-track pulls loose, you are gong to end up building a new fixture.

You might also consider picking up a t-slot bit and simply cutting your own track into the plywood. You end up with your total target thickness being the same and you don't have the expense of buying T-track. I cut lots of slots and use T-bolts in them and haven't had one tear out yet, including slots I cut in a piece of particle board for a clamp rack I built more years ago than I can remember.


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## Holbs (Nov 4, 2012)

i always wondered how making own track, stands up to abuse over time. for now, i'll use this T-Track. got hold of 24' of the stuff to use up somewhere


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## Slemi (Mar 7, 2014)

If You don't plan to use hold down clamps, there isn't much pulling force out. If You just plan to lay fence on the t-track and fix it then just make t-track flush with surface. this way there is no pull-up force and You are good with just a little "meat" for fixing track. If You plan to use hold down clamps, that s another story, then You need to fix the track very good.


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## Holbs (Nov 4, 2012)

one T-Track will be used soley for stops, so that's no problem. It's the second T-Track that willl be used to hold down a piece of wood. I have the option to slap in another 1/2" or even 3/4" underneath the 1/4" of "MEAT" for more of a foundation. I just always wondered this because of 3/4" table sleds that use T-Track and toggle clamps. Just seems to me there is very little 1/4" "meat" to rely on a toggle clamp holding a piece of wood on a table saw safely.


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