USING DEWALT 745 with Freud Box Cutting blades...questions...use w Incra I-box

[tom coleman]

I removed riving knife assembly and installed Freud box cutting blades for 1/4 or 3/8 inch cuts. Plenty of room on the arbor and very nice cuts.

In order to change blades, I had to remove sheet metal blade guard roughly 10x12 inches held in place by 4 screws. PIA to change blades. I am thinking of leaving this guard and rivving knife un-installed. Do you see any dangers in this approach?

I am awaiting delivery of Incra I-box. Would appreciate comments and suggestions from Incra I-box users

[John Donhowe]

I'm not familiar with the 745, so can't comment on the sheet metal (which I assume is a shroud)- removing it might impair dust collection.

As far as the riving knife, it should be okay to leave off, as long as you are using the blades to make box joints. In that situation you aren't making through cuts, so there aren't cutoffs which could kick back. When making through cuts, though, always use the riving knife.

[Charles Lent]

I can't comment on the 745 saw either, as I have never even touched one, but the Freud Box Joint blade and the I-Box jig are the perfect combination for making box joints.

I make a lot of boxes, and I use my Unisaw with a Freud SBOX8 blade set with the Incra I-Box jig to make the corner joints. The boxes that I make are mostly from Baltic Birch plywood which splinters and chips very easily, but not if done properly using the I-Box jig. Cutting plywood requires that the MDF backer in the I-Box jig be moved for each new setup, so that this backer receives a new cut that is exactly the right size and in the right position for the box joints being made, to eliminate the back side chipping. This is a MUST for making box joints in plywood, but a good idea for any material. The jig comes a sacrificial piece of MDF to use as the backer board, and it can be moved right-left and even turned upside down to allow for 20-30 box joint setups before it needs replacing. (for best results you need to use a fresh position for each box joint setup). Incra sells a 3 pack of these backer strips for $10, but you can make your own for much less.

Get a 2' X 4' piece of 1/4" MDF (about $6.50) and make replacement copies of the sacrificial MDF backer that comes with the I-Box jig. A 2' X 4' piece of 1/4" MDF will make about 20-24 copies of these backer strips, depending on your saw blade kerf width and layout. There are 4 countersunk holes that need to be drilled, and these can easily be drilled with a drill press positioning setup and counter sinking drill bit with two positioning setups or only one positioning setup needs to be made to drill the through holes ( flip side to side and end to end) if you drill the countersinks as a second step. They're easy to make. You can make them yourself in about an hour much cheaper than buying them from Incra, and you will have a several years supply of them, made from just one 2' X 4' piece of 1/4" MDF.

You might also want to purchase a box bottom slotting bit from Lee Valley http://www.leevalley.com/US/wood/page.aspx?cat=1,46168,46176&p=47818. These are special small diameter slot cutting bits that are available in several slot widths, with an end bearing. They allow cutting a stopped slot in the bottom edge of all 4 sides of the box very easily. With the bit in a router table and set for the correct height, and the 4 sides of the box dry assembled and clamped together, the box sides can be placed over the bit and the slot for the bottom can be cut all the way around the inside of the box in one pass, and none of this slot will be visible from the outside of the box. A slight rounding of the corners of the box bottom will be necessary for it to fit, but if done carefully, it will be completely invisible, once the box has been fully assembled.


Charley