Replies

1. 
   Sphere | Jan 31, 2004 02:34am | #1

   awe, c'mon...do the math. it's good exercise for the noggin. use it or lose it.

   Go Stab yourself Ya Putz! Ya think I Parked here?
2. 
   johnhardy | Jan 31, 2004 02:39am | #2

   I agree with Sphere. You can easily calculate exactly where the router bit will cut. Just put your straignt edge that distance from the "line". No big deal here.

   In fact, if you're wary of the math, cut two blocks the exact width of the "offset". Place those on the cut line, clamp them, and then clamp the straing edge so that it abuts these blocks. Remove the blocks and you're good to go.

   John

1. 
   dirtstirrer | Jan 31, 2004 07:30am | #3

   John and Sphere,

   Could be wrong, but isn't he looking for a 29/32 bit with a bearing, not a 29/32 bearing?Steve

1. 
   johnhardy | Jan 31, 2004 08:23am | #4

   He's looking for a 23/32 bit, with bearing. We're saying that you can use a non-bearing bit if you just set the "fence" differently. I'm personally a fan of jigs rather than using the math each time and that's why I suggested using two boards to set the fence to the correct offset.

   John

1. 
   dirtstirrer | Jan 31, 2004 08:44am | #5

   I see, I stand corrected.  Been a long day I guess. 

    BTW, do you still have any slides and hinges left?Steve

1. 
   johnhardy | Jan 31, 2004 07:27pm | #9

   Lots of slides and loads and loads of Blum Euro hinges left. I'm leaving in a few minutes for a weekend away but if you send me an e-mail with what you'd like I'll get back to you Monday.

   [email protected]

   John

2. 
   tv190s | Feb 02, 2004 01:17am | #10

   Thanks all for the replies. No, not new to woodworking, but yes I have not done many dado's. I have seen the T square jigs before that Sgian mentions. It was just a simple inquiry really, and me being logical just wondered why the bit makers aren't making a bearing plywood bit.

   Seems like it would be a nice bit to sell, but guess I'm wrong.

   Thanks again.

   Matt

3. 
   SgianDubh | Jan 31, 2004 01:32pm | #6

   Yeah well, I understand where all you fractions calculating hotshots, and whizzes with spacers and the like are coming from-- done plenty of both those tricks and more myself. (Abandoned the fractions many yonks ago because I'm hopeless at them, and yes, I've seen the stooshie going on in the Decimal Inch thread. Anybody seen a foot divided in ten 'inches' like surveyors use? Now that threw me for a loop the first time I came across it, ha, ha.) But I also understand where campbem might be coming from too--- maybe somewhat nervous of the whole thing, and perhaps a bit new to woodworking and routing? Such a question phrased as it is reeks of inexperience.

   Dado, defined as a channel across the grain of course, aka housing or trench in Britspeak can easily be done with a router, a bit and an accurately homemade T square-- just 2 bits of wood screwed and glued to one another. Once the T square is made the short leg at the top of the T fits against the straight front or back edge of a test panel and the long leg sits on the panel face which is to be housed (dado'd). Cramp it in place at both ends of the long T leg.

   Shove a bit in the router collet, set it to a depth, fire up the router, and holding one edge of the router base against the long leg of the T square guide, rout right through the short leg of the T and across the panel. Bingo. You now have a registering slot cut in the T square which in future can be lined up with a simple pencil mark. No calculating, no additional measuring, and no spacers required for the future as long as you reserve that T square for that diameter of bit. Make a few T squares like this for various bit diameters and you have a useful collection of workshop aids. 

   A router with a straight edged base is obviously run with the straight edge against the long leg of the T, but routers with round bases are a bit trickier because the cutter is often not perfectly centred in the base. On this type mark one point on the circumference of the base with a blob of paint or similar and always line the paint blob up against the guide to ensure a consistently straight and registered cut.

   For cutting grooves, channels, slits, etc.,  in the length of a wide panel where the side fence is inappropriate make up another type of jig. Cut out a long piece of 6 mm ply or MDF about 200 mm wide. Attach to one face and along one edge a piece the same length of 12-- 18 mm MDFor ply about 100-- 120 mm wide making a guide that's L shaped as looked at from the end. Again, install a bit in the router and run the edge of the base along the short bottom leg of the L. This will trim the 6 mm part of the jig providing a register for pencil marks on the panel. Again you can make a selection of these jigs for different bit diameters.

   As to 'plywood' sized bits, I've never bothered with them. I run my grooves or housings using any bit that has a diameter about half the panel thickness. Then I set up the hand held router (or overhead pin router, inverted router, or spindle moulder) with a side fence and run a rebate (rabbet) or tongue on the edge or end of the shelf, middle panel etc., to fit-- I usually aim to cut the tongue or rebate a bo'hair fat for preference and trim with a shoulder plane as required. It makes for a stronger joint anyway because of the additional returns and I've never noticed that I'm particularly slow at the job, ha, ha-- ha, ha, ha. Slainte.

   Website

   
   

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   Edited 1/31/2004 5:46:01 AM ET by Sgian Dubh

1. 
   Sphere | Jan 31, 2004 04:56pm | #8

   Thank you for saving me a bunch of typing..bone chilling cold here at -7 * F..

   I might add, I have made bearing enlargers..by drilling a 1/4 or half inch dia. hole in Lexan, and turning to a disk of whatever dia. I need..drop of superglue to stick it on the existing bearing..works great.

   Go Stab yourself Ya Putz! Ya think I Parked here?

4. 
   Scrit | Jan 31, 2004 02:21pm | #7

   For top bearing dado cutters try Jesada or CMT (don't think they do undersize plywood bits), but I'd really suggest that Sgian's approach is FAR better (then again I do it in a similar way). And if my housing is a tad undersized, then a swoosh or two with the side rebate plane will take care if that easily.

   Scrit

   
   

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   Edited 1/31/2004 6:25:03 AM ET by Scrit

   
   

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   Edited 1/31/2004 6:26:59 AM ET by Scrit

5. 
   Routerman | Feb 02, 2004 05:09pm | #11

   Free video snippet here at FWW might be worth a look.