Looking for magazine article

[Chris Knight]

In the latest (Tools & Shops) issue of FWW there is a short piece on squaring a crosscut sled involving a procedure making five cuts. I have recently seen an article that inlcuded this method along with four others in, I think, a different magazine (ie not FWW).

Can anyone point me to it?

 

[SammyQ]

Duno erzactly where the article wuz....butttttttt....i reckon I have the original web posting saved somewhere on one of three hard drives. If someone else doesn't recognize the mag. and article, pm me and I'll dig it out, then email it to you. Sam

 

[ProShop]

Chris,

I'm pretty sure I know the method your after. if you don't find it, I can get you a copy scanned or photo copied and send it to you if you wish.
It's in my Felder manual.

 

[Scrit]

I've been doing this on procedure on Altendorf panel saws for a few years now, and the technique is as follows:

1. Find a piece of "scrap" MDF or MFC about 1 metre square. Not solid timber. It doesn't need to be 1metre but 2ft square is really the minimum
2. Trim one side using the fence of your sled as the datum. Make this a "dust cut"
3. Turn the test piece so that the newly cut edge is resting against the sled fence. If the fence is to the rear of the piece, this means turning 90 deg. clockwise, if the fence is to the front then turn anti-clockwise.
4. Continue making cuts until you have trimmed all 4 sides
5. Turn the test piece through 90 degrees and take a 4 to 5mm strip off the edge of the piece. This is the first edge that you sawed.

Mark the leading end (i.e. the end nearest the outfeed side of the saw) of the trimmed strip then break your strip in two and compare the thickness of the two ends. If they are the same thickness at each end your sled is square. If the front (marked) end is thicker than the rear then the outboard (left hand) end of the fence needs to be moved towards the rear (outfeed) of the saw. If the rear end of the strip is thicker then the converse is needed (i.e. move the outboard/left end of the fence towards the infeed end of the saw). The discrepancy shown by this test will be four times the actual discrepancy at the test pieces side length from the sawblade (if that makes sense)

In the above description it is assumed that you will be cutting with the material to the LEFT of the sawblade at all times as on a conventional panel saw. A "dust cut" is a trimming cut meant only to square the edge of the material and nothing more. Only the last cut needs to be thicker.

Scrit

 

[George_N]

This link might be useful.
http://32mm.dalrun.com/System_Tools/Cutting/5cut.html

George

 

[SammyQ]

This last post from George is the one I had in mind - it works. Sam

 

[Chris Knight]

Thanks guys, very helpful.

 

[Freetochat]

Am I missing something obvious, but by using this method, is the error not multiplying on each cut?

 

[ProShop]

John


Scrit Wrote

The discrepancy shown by this test will be four times the actual discrepancy at the test pieces side length from the sawblade (if that makes sense)

.

In a way your right. But look at what Scrit says above. It does seem a bit strange at first, but if you think about it your making all 4 sides equally out of square (if the fence is out of alignment) so that the 5th cut gives an incredible degree of the fence/sledge accuracy (or not as the case maybe).

If you have a machine that can take large sheets this is the most accurate way of setting up a sliding carriage and fence. But as Scrit says it's best if you use a board of about 900mm or above. That way you can see the discrepancy much more clearly and you can set the fence/sledge with much greater accuracy.

Hope this helps.

Theres no reason why one couldn't rip an 8ft board in half and the difference at each end is negligible using this method