Replies

1. 
   mikeddd | Jul 03, 2009 08:57am | #1

    If you take your time and make a few passes you should have no trouble doing what you are trying to do. The only times I have had bad experiences with a router is when I got greedy and tried to remove to much material with one pass. But I am not an expert on the mater.

   Mike

    

2. 
   whitedogstr8leg | Jul 03, 2009 09:05am | #2

    A 1/4" bit a bit tiny to be cutting through 3/4" plywood in one "gulp".  Either use three or four passes, or get a spiral type bit.  The "problem" with cutting slots in plywood lies not in the wood parts, but the glue joints holding the plys together.  For now, just use small passes, about 1/4" or less deep. 

3. 
   Spalted | Jul 03, 2009 05:24pm | #3

   Your taking too big a bite, i would say. Try doing it in 3 passes. I do it all the time with a router table- set the fence, start the stopped cut by lowering the work onto the bit at your mark and push slowly through until you reach your stop mark. raise the work, then shut off the router. Raise the bit and repeat.

4. 
   mikeddd | Jul 03, 2009 05:39pm | #4

    Here are a couple of jigs I built for making slots as you are trying to do. http://forums.taunton.com/fw-knots/messages?msg=47136.18   I could not find this post when I posted last night. These jigs took me a couple of hours to make, but once made set up time for cutting a slot is next to nothing, hope this helps or gives you some different ideas.

   Mike

    

5. 
   Frank Vucolo | Jul 03, 2009 06:01pm | #5

   I agree with the others about taking your time with the router - multiple passes.

   However, why not just refine your original technique? You can get a straight line with your jig saw by clamping a straight edge to the jig to guide the saw. Clamp the guide, make a cut between your drill holes, move the guide over 1/4 (or whatever the width of your slot is) and cut the other line.

   If it's a jig you will use and adjust a lot, and if it is appropriate, you could consider using T-Track like this stuff available at Woodcraft.

   View Image

1. 
   davcefai | Jul 04, 2009 12:37pm | #7

   If you cut 3/4" ply with a jigsaw the blade may bend a little so that parts of your slot may not have parallel/vertical sides.OK it depends on the blade quality too.

1. 
   Frank Vucolo | Jul 04, 2009 04:40pm | #8

   If you cut 3/4" ply with a jigsaw the blade may bend a little so that parts of your slot may not have parallel/vertical sides.

   OK it depends on the blade quality too.

   Hi Dave,

   I suepect blade quality, tool quality and technique all come into play; I would also think that, given tools and techniques of equal quality, the result would be cleaner using the router.

   However, we have to keep in mind that we're making a shop jig from plywood. I'm sure the jigsaw result would be fine.

   Frank

1. 
   davcefai | Jul 04, 2009 07:00pm | #9

   "I'm sure the jigsaw result would be fine"For many purposes, yes. In this case the OP wants bolts to slide through the slots. Any imperfections will detract from smooth operation.

1. 
   whitedogstr8leg | Jul 04, 2009 07:05pm | #10

    I'd use the jigsaw to cut an undersized slot, then finish up with a router bit the right size for the slot.

6. 
   northhouguy | Jul 03, 2009 07:08pm | #6

   Like my Daddy used to tell me at the dinner table:  "Take small bites, Son..."

   Then he'd knock me off the chair... `~<;^)-+-<

   Really, I did the same sort of thing you did and had the same troubles.  Lighter cuts were the answer.

   Fred