Another dado question

[HowardH]

I am going to install an Incra miter channel into my phenolic router table.  It doesn't have one at the moment but there are some jigs out there I want to use that require one.  The table is 3/4" and the miter channel is 1/2" thick which leaves only 1/4" left under the channel for support.  Is that enough with phenolic?  I looked at the woodpecker's site and it appears they have done the same thing but I couldn't see if they had added any support under it.  Also, the channel requires a 1 1/8th inch wide dado.  I plan on using a guide rail and OF1400 with the guide rail attachment and a 3/4" straight bit.  Is it simply a matter of eye balling the lines on each side that represent the width of the channel?  I suppose I can eyeball one side, and then use the micro adjust to add another 3/8ths but since it's metric, I'm gong to have to guess on how many turns it's going to take.  Ideas? 

 

[semenza]

I would route down the center line, and then make a second pass that will get it close but under sized, then test the fit and sneak up on it. 

Seth

 

[tiralie]

The table is 3/4" and the miter channel is 1/2" thick which leaves only 1/4" left under the channel for support.  Is that enough with phenolic?

I don't think so, but it depends on how much support is in the table. To be safe and 'cause I am hard on stuff, I would reinforce the underside with some steel or aluminum "L" channels. I would tap some holes into the underside of the table and attach the L channel with some machine bolts.

I plan on using a guide rail and OF1400 with the guide rail attachment and a 3/4" straight bit.  Is it simply a matter of eye balling the lines on each side that represent the width of the channel? 

Hmmm, not sure I understand "eyeballing" the lines. I would take the channel and place it upside down on the top of the table where you want it to be and trace some lines marking both the outside of the track. I would then line up my bit on the inside of one line and route. When completed I would move it over and line up the outside of the bit on the inside of opposite line. I would leave my set up there and try the channel in the dado. If it was too tight, I would just route the same line creeping up on it till I got what I wanted.
Tim

 

[HowardH]

The table is 3/4" and the miter channel is 1/2" thick which leaves only 1/4" left under the channel for support.  Is that enough with phenolic?

I don't think so, but it depends on how much support is in the table. To be safe and 'cause I am hard on stuff, I would reinforce the underside with some steel or aluminum "L" channels. I would tap some holes into the underside of the table and attach the L channel with some machine bolts.

I plan on using a guide rail and OF1400 with the guide rail attachment and a 3/4" straight bit.  Is it simply a matter of eye balling the lines on each side that represent the width of the channel? 

Hmmm, not sure I understand "eyeballing" the lines. I would take the channel and place it upside down on the top of the table where you want it to be and trace some lines marking both the outside of the track. I would then line up my bit on the inside of one line and route. When completed I would move it over and line up the outside of the bit on the inside of opposite line. I would leave my set up there and try the channel in the dado. If it was too tight, I would just route the same line creeping up on it till I got what I wanted.
Tim

That's what I meant by "eyeballing"  Lining up the bit by sight to the lines.  I also thought about getting some 3/4 mdf about 4-5" wide and glueing it to the underside where the channel will be to provide some support. How would that work?  The table currently overhangs my cabinet by about 4" in the back and 1" in the front so the cabinet sides currently add some support already.

 

[tiralie]

That's what I meant by "eyeballing"  Lining up the bit by sight to the lines.

LOL, Ok. I am going to get a BCTW KM-1 to make these like Paul shows in the video. Eyeballing takes too long.
Bridge City KM-1 Kerfmaker User's Guide

I also thought about getting some 3/4 mdf about 4-5" wide and glueing it to the underside where the channel will be to provide some support. How would that work?  The table currently overhangs my cabinet by about 4" in the back and 1" in the front so the cabinet sides currently add some support already.

Without seeing it, I think that if you have that much support from the sides it should be OK without the MFD. The
Tim

 

[HowardH]

I went at lunch down to Woodcraft and they had a Jessem phenolic table that was setup exactly as I need it. They had dadoed the miter channel into the phenolic without additional support with the table being .75" thick.  The cabinet sides supported it so that's what I'm going to do.  BTW, that little gizmo Paul has from BCTW - $70+  [scared] [scared] [scared]  I think I'll sneak up on this one.