Why two miter slots?

[unknown poster]

I'm getting ready to add a miter slot to the left side of my 21829 to hold a panel cutting jig. I've looked at the relevant articles, done some searching here, and I have a good idea of what I want to build. I'm planning to use MDF and probably Incra aluminum slots.

I've noticed that the extruded aluminum miter slots for the BT3, and most homemade equivalents, use two miter slots a few inches apart.

What is the advantage to having two slots, when they are so close together? Are there some jigs that work better with a closer/farther slot? I'm considering just building with just one slot, probably as close to the table as possible.

[LarryG]

I don't know what the thinking was for the dual slots in the Ryobi-made table, and I don't know what the advantage would be. Possibly to accomodate miter gauges with different-sized heads? I can't recall which of the two I used with my standard-size gauge. IIRC the head would clear the blade with either slot; the leftmost slot just moved the gauge farther away from the blade.

I had not noticed that "most homemade equivalents" have two slots, but perhaps they do. The one I built for the right side of my BT had only one and I never needed a second. I could have easily gotten by with just one on the left, too. Having a slot on both side is handy when you move the rip fence to the other side of the blade, or for a crosscut sled with two runners. But one on each side is really all you need.

While the dimension varies a bit from brand to brand, most full-sized contractor and cabinet saws have their miter slots ~6" from the blade. You might want to position yours similarly, so you will be able to use off-the-shelf miter gauges, tenoning jigs, etc.

[reddog552]

Miter slots

I have used both of my slots with my tenoning jig.One for small tenonons other for lager ones

[pelligrini]

I'm not too sure why the OEM was a dual slot table. It might have been a bright idea by the designer that wasn't all that well thought out. I've seen a few shop made versions use dual slots too. The OEM ones not being a T-slot miter does have drawbacks.

I did mine out of MDF, Incra extrusions and aluminum angle. http://www.bt3central.com/showthread.php?t=34202 Mine is a dual slot, but one of the slots is a T-track. The T-track is really handy for featherboards, holddowns and such.

[unknown poster]

I like the T-Track idea, I might go with that. I saw a few combo tracks with the miter and t-track in one unit, I'll have go find those again to see if I like thier design or if I would rather have two seperate units.

[crokett]

The disadvantage of two slots and having a jig with two bars is the setup is a bit more complicated and there are two things that would need to be squared up to run in parallel.

[Salty]

I like the dual slots because it extends the usable reach of the featherboards. I can move to the outer slot for wider material without having to move the miter slot table.

[RAV2]

Bought the OEM dual slot from M and D and have been very happy.

Not too expensive ($36.71) and installed easily with a couple of holes.

http://www.m-and-d.com/TTI-4060310.html

Also found on Amazon:

$33 plus shipping - http://www.amazon.com/MITER-SLOT-TAB.../dp/B000P8N1EO


Look around here for instructions.

[Bill in Buena Park]

...Mine is a dual slot, but one of the slots is a T-track. The T-track is really handy for featherboards, holddowns and such.

Erik, that's a really great idea. I did mine with two miter tracks instead, but like the versatility of your version. I was thinking that since a majority of dark-side sleds used two miter bars - still not sure why - maybe to REALLY eliminate any wiggle if one runner isn't a good fit - that maybe I would try putting two miter bars on my sleds, thinking the same thing (two parallel bars at least 1.5 inches apart would act like those 12in apart...) I ultimately only use one miter bar per sled (because they fit really well ), but I use the outside bar for smaller sleds, and the inside bar for larger ones.

[unknown poster]

Thanks for the feedback folks. I don't like the factory rails because they don't allow for a t-slot type miter bar.

I think I'm going to build an MDF extension with an incra t-track on one side and an incra miter slot on the other. Right now I'm only planning to build a crosscut sled to replace the smt, if I use an incra bar I should be able to get it snug in the slot so I only need one bar for alignment.