How do I cut a slot through 1 3/8" material?

[RickT]

I'm using 3/4" mdf and 2 sheets of 1/4" tempered hardboard for my router table, with 1/16" laminate on the top and bottom. The total thickness will be a little over 1 3/8". I'd like to cut two slots for the bolts holding down the fence. Actually, I was thinking of using keyhole slots to allow me to easily mount and remove the fence without completely unscrewing the bolts. (The router table will be the right wing on my BT3100, so I'll need to remove the fence when cutting wider stock on the BT.) How do I cut the slots? I need to go through 1 3/8" material. I considered a spiral upcut bit, but the Whiteside bit I'd need (1/2" shank, 1 1/2" total cut length) is $40.[:0] Is that my best option? Any other ideas?
Thanks,
Rick

[scorrpio]

Are you going to laminate all these layers togeather? You could cut slots before you glue it all togeather. Once you slot one, you can use it as template for the others.

If you already have it laminated that way, you can drill at both ends of the slots wth a drill press, to mark the slot on both sides. Then, you can use a shorter (3/4" bit) to first cut halfway from one side, and halfway from the other.

[Tom Miller]

Rick,

You might consider using T-track in a dado. I made my dados a little longer than the t-track so I could remove the fence along with the bolts by just loosening the bolts and sliding the fence over. Like so:






This is the back of the fence, showing the bolt knobs that hold the fence down:




Regards,
Tom

[Black wallnut]

Have you considered mounting "T-track" into your top. If that's not an option then my suggestion would be a spiral bit. The cost for bit is high but it is a very usable bit to own.

[LarryG]

Replied once, realized I'd misread your question originally, so deleted that and am trying again:

You could drill a starter hole at one end and then cut the rest of the slot with a 1-1/2" CL straight bit, making multiple passes. A bit like this will only cost you about $15 (and that's a Whiteside; generic brands should be much less).

EDIT to add ...

Option 2: If you really want keyhole slots, that might well be the easiest approach. Drill a starter hole, make a first pass with a 1/4" dia bit to remove most of the material, then chuck up the keyhole bit (about $15) and finish up.

Option 3: You could also forget the slots or tracks entirely and design your router fence so it clamps to the BT's rip fence.

[vaking]

If you decide to cut slots all the way through - you can use straight or upcut bit. Upcut is more expensive but very usefull in a long run. Regardless of a bit you are using when you need high precision deep cut - make it in 2 steps. The first step is to make initial cut in multiple passes increasing the depth no more than 1/4" each pass. The cut in this step should leave some wood on the sides for the final cut, about 1/16" on each side, so make your slot at this stage a little narrower. The second step is to cut full depth at once but taking off only the last 1/16" to clean the edge. This is the method used for countertops when clean edge is needed, like undermount sink.

[Thom2]

or ..........

forget slots and t-track entirely and make a fence that mounts on the rails ...

[LarryG]

Hey, Thom, that is COOL! I don't know whether that's a method a lot of BT owners have used, but I do know that I cannot recall seeing it before.

I have a partial set of rails that are earmarked for a semi-wide-table extension wing that'll give my BT a rip capacity of about 30" with the scale on the rails properly indexed to the blade. I have a dedicated router table but am going to hang a second one in this new wing, for light-duty work. I pretty much had everything figured out except how to mount the router fence ... but now that problem is solved, too.

Seriously, that is COOL!

[Napoleon]

Ditto the above! (or is it ibid???). Seems like a real simple solution. Definately going to investigate that one...
Mark

[RickT]

Thanks for all the great input. I think I'm going to buy the Whitesie upcut spiral bit. I'll probably use a forstner bit to drill the larger hole at one end so I can remove the saw without completely unscrewing the bolts.
Thanks again,
Rick

[gonesailing]

If I were going to make slots through the 1 3/8 material, I think I would drill the end holes and then use a saber saw to rough cut the slots. That would save a lot of wear and tear on whatever bit you use to clean it up.

In fact, rough cutting the slots by plunging a circular saw would work as well, although you would have to finish the ends with a saber or hand saw.

Mike

[waterpro]

Can you get those T-tracks at home depot? If so where are they located?

[LCHIEN]

waterpro, the t-tracks cannot be found at ordinary hardware stores, you have to go to woodworking specialty stores like Rockler or woodcraft.
There are a number of on-line stores, too, some specialzing in just T-tracks.
This is probably what you want:
http://www.rockler.com/product.cfm?page=5209
comes with all the knobs and bolts you might need.
Easily cut into two 2' pieces.

[LCHIEN]

RickT
my advice would be to use T-tracks. That's the most common method for fence attachment for routers for a reason. Its easy and cheap and looks nice. Several photos were posted showing partial t-tracks for the fence.

I would not cut slots all they way thru my 1"+ thick table. It weakens the table incredibly and is a pain to do.

[Tom Miller]

quote:Originally posted by LCHIEN

I would not cut slots all they way thru my 1"+ thick table. It weakens the table incredibly and is a pain to do.

Yeah, good point, Loring. I don't think anyone touched on that 'til now.

Regards,
Tom