Attaching T-Track?

[Jay Yoder]

I started working on a drawer assembly jig tonight and ran into an issue with the Rockler aluminum T-slots I am using. It required almost a 1/2" deep dado and I am now left with not much meat left to screw them down. I was wondering how you all would proceed. I have thought of the following solutions:

1) add a second 3/4 layer to the bottom of the dadoed piece, but this would make the jig too heavy.

2) use epoxy

3) use super glue

4) any other options?

[Michael Peet]

Jay, which T-track are you using? I recently used some from Rockler on my crosscut sled. It required 3/8" deep dados, which left 3/8" of material underneath in the 3/4" ply. It was plenty.

This is the stuff: http://www.rockler.com/product.cfm?page=21967&filter=t-track

http://www.sawmillcreek.org/attachment.php?attachmentid=147748&d=1270934164

Mike

[Jay Yoder]

I had picked up 2 packages of their T-track kit. I was surprised at the depth too! But it was what I had so...It seems that the older kits had the 1/2" tall track, but now they are 3/8". I got these when the local Rockler closed a couple years ago.

[Michael Peet]

Maybe you can drill more holes and just use lots of shorter screws?

Mike

[Thomas Canfield]

The 1/2" deep T-track works well using 1/2" MDF (1/2" plywood often less than 1/2" thick) for top surface and just butting pieces of MDF against the T-track eliminating cutting dados. You can then use a double thickness of 1/2" MDF (or one layer of 3/8" or 1/2" plywood for bottom layer) and have some wood for thread engagement on screws. You can also rough up the outsides of the T-track and use Liquid Nail as an anchor. I do not recommend using SuperGlue for that use due to it becoming brittle. Epoxy would work well to fill gap but again I would tend to want to rough up sides.

[Jay Yoder]

Thomas, I wish I had thought of that one earlier, the dados are already cut to 1/2" deep and pieces are sized. I never thought of using construction adhesive. Only concern I have is that once glued the feasability of reusing the tracks in another project is eliminated. But I guess it is not that big of a deal...Not sure I could find 1/4" screws that would hold in baltic birch...

[Bill Huber]

I get some small T type nuts at Ace Hardware and they worked fine with that T track in 3/4 in MDF.
The ones I got were 6-32, with flat head screws and cut them off so they did not stick out the back. The nuts are not exactly like T nuts in they do not have the spike that comes out. I use a Forstner bit to make a small countbore in the button.

[Jay Yoder]

Bill,
the thought of using T-nuts on the back side never crossed my mind. I found some on the Lowe's website that are 6-32 x 1/4 x 9/16. My concern being that there is already less than a 1/4" of thickness left and counterboring another 1/16 for the nuts would reduce further, but there are not that big of dia. That is the only way I can think of to allow the reuse of the track. Maybe I should just epoxy/construction adhesive them in and be done with it...any experience with the eposy or construction adhesive in this application?

[Bill Huber]

Bill,
the thought of using T-nuts on the back side never crossed my mind. I found some on the Lowe's website that are 6-32 x 1/4 x 9/16. My concern being that there is already less than a 1/4" of thickness left and counterboring another 1/16 for the nuts would reduce further, but there are not that big of dia. That is the only way I can think of to allow the reuse of the track. Maybe I should just epoxy/construction adhesive them in and be done with it...any experience with the eposy or construction adhesive in this application?

Jay the ones I found at Ace were just about like a washer, I am sure there is some real name for them. They were flat and just had little bumps on the back.

I think you could grind the ones at Lowes down.

[Gene Howe]

I just finished a "T" track/"T" bar based sawing guide. I used JB Weld for the same reason. Not enough meat on the bottom side. It seems to hold well, though time will tell.

[Carl Beckett]

same thing - deep T track into MDF.

I used 5 min epoxy.

Becareful to have somewhere for the excess epoxy for squeezeout. I put a full film layer it on the bottom and partway of the sides of the slot.

Then T track, and a stiff hardwood clamped over the top to ensure its flush at the surface.

Several years use - no issues.

[Myk Rian]

I use #4 X 1/2" screws. You don't need to hold T-track all that firm. Friction will hold things steady.

[Joe Scharle]

These will do the job using a standard type T-nut, which you'll have to snip off some of the spur or use the flat style with bumps.

http://www.ncwoodworker.net/pp/data/194/0087.JPG

A slight counterbore on the back of your jig gives T-nut clearance.

http://www.ncwoodworker.net/pp/data/194/Taper_Jig_Function_004.jpg

You will need to overbore the T-track holes enough for the barrel of the T-nut to draw up into the T-track. If you-re using actual 3/4 BB, this will work just fine.

[Jay Yoder]

Those are some small screws! May be a silly question, but how would one drill the counterbore? I checked all my countersinks and none would fit into t-track far enough to actually do anything. Am I missing something?

[Joe Scharle]

You would be drilling a larger hole through the existing T-track holes. Aluminum drills just as easily as any hardwood. Just a drop of 3in1 oil in each hole.
The hole has to be just large enough for the T-nut barrel/sleeve to fit into from beneath. Can't remember the drill number, just mic the barrel and go 1 size bigger.
No need to re-countersink the existing holes.
The screw will draw the barrel up into the hole.
I've used yards of the 1/2" track before the thinner stuff became available, and used this procedure to good effect.

[Jay Yoder]

Joe,
So you drill out the hole (and create new ones) for the inserts to pull up thru? If one had full thickness, and didn't need to go the tee nut route, how would one countersink the holes that are added?

[Joe Scharle]

I use these...they will just fit.

http://www.leevalley.com/US/hardware/page.aspx?p=32308&cat=3,41306,41328

I always use the T-nuts. Wood screws of this small size will not hold against any kind of stress or load.

[Jim O'Dell]

I'd use a larger drill bit on a drill press with the stop keeping it from drilling all the way through. With hold downs on the track. (this alludes to my DP accident 13 months ago. I still haven't gotten feeling back in my little finger.) It won't make a perfect countersink, but enough that it will work. Jim.

[Jay Yoder]

Joe-thanks for the link. Not sure the LOML would go for an $20 for two drill bits. She is on her one-woman crusade to reduce our spending, can't say she is wrong :)

Jim-Good idea to just use a bigger bit to create a quasi-countersink.