Thread: The Triton Woodworker - Issue #37

are we playing spot the typo on this edition?

Bottom of page 11, quality instead of qualify

Thanks, Doug. We try to keep the Newsletter error free, but sometimes a few slip by.

Our webmaster will soon re-post with the error corrected.

Who wrote the article on kerfing?
I do a lot of kerfing as a part of my "demonstrations", which gets lots of interest from everyone who sees it. I was surprised to see that the article doesn't make any mention of the calculations/formulas to find out the amount of cuts for a 90 degree cut or for that matter the spacings between the cuts. I have found that using a mark to go by for the spacings is good but a to achieve multiple kerfs the same you need to use a jig to get identicle bends. With a combination of the two formulas you can take any piece of timber and know instantly the number of cuts to make, the spacings formula is slightly more complicated but not hard.

Originally Posted by doug the slug

are we playing spot the typo on this edition?

It's only a measure of how closely we read it.

Page 10, Varnish vice vanish.

Originally Posted by Bulli

It's only a measure of how closely we read it.

Page 10, Varnish vice vanish.

It's not me, it's the bloody spell checker! Damn that Bill Gates ! :eek:

Does anyone know any formulas for kerfing?

Capital T for Triton

Originally Posted by Sprog

Capital T for Triton

their logo has a small 'T'

When I went to school many years ago we always started names with a capital letter

I'd love to hear from guys with experience. I've just kerfed some boards for the head board of a cot using these:

To decide on the spacing between cuts: you make a line at the start of the curve, and another the same distance away as the desired radius of the curve. Make your first cut at the start of the curve. Clamp the straight end of the board then lift the free end until the edges of the kerf touch. Measure the height of the second mark from the bench top - this is the distance between cuts to make a curve of the desired radius.

To work out how far along the board to make cuts: get your calculator out and go 6.28 (2 pies) x radius x angle you want/360 (for example, a 45 degree bend with 150mm radius would be 6.28x150x45/360 = 118mm
Anyone else?

Originally Posted by Sprog

When I went to school many years ago we always started names with a capital letter

Somebody should have told george

Originally Posted by channa

I'd love to hear from guys with experience. I've just kerfed some boards for the head board of a cot using these:

To decide on the spacing between cuts: you make a line at the start of the curve, and another the same distance away as the desired radius of the curve. Make your first cut at the start of the curve. Clamp the straight end of the board then lift the free end until the edges of the kerf touch. Measure the height of the second mark from the bench top - this is the distance between cuts to make a curve of the desired radius.

Awesome, well done. Try this website but don't bend the workpiece backwards as they have in the diagram. I disagree with the amount of cuts required though. http://www.cabinetmaking.co.uk/sawkerf.htm

Originally Posted by channa

To work out how far along the board to make cuts: get your calculator out and go 6.28 (2 pies) x radius x angle you want/360 (for example, a 45 degree bend with 150mm radius would be 6.28x150x45/360 = 118mm
Anyone else?

As to how many cuts. I leave about 2mm of timber and have found that for a 180 degree curve, you take the thickness of the timber in mm and subtract 1. So for 35mm timber you make 34 cuts, for 19mm timber you need to make 18 cuts. If you don't quite make 180 degrees, get a triangular file and take a small amount off each shoulder.

Woody

Originally Posted by Gumby

Somebody should have told george

LOL

This is why I admire builders.

I have been sitting here, with drawings of triangles, circles, scribles of Pye and all sorts of things trying to calculate "the kerfing formula".

Came up with variables of

Thickness of timber to be Kerfed = T
Width of kerf = K
Remaining thickness of timber to be left = V (for veneer)
Radius = R , but then I had to modify this for IR and OR for inside and outside radius.
Then I had N for the number of cuts and D for desired angle.

By this stage, a scrap of the stock would have been cut a few times to work out how thick or thin to leave the veneer and then this cut repeated a few times to see how many were needed for a 90 degree curve.

From that, a guestimate for the RP (Relative positioning of the cuts) to give a CE (Close enough) result that would then be slightly modified in the final run.

The Final run more often than not needs some tweaking here or there anyway.

I enjoy both mathematics and woodwork. I also enjoy wine and beer. In moderation they are both fine, but too much of both of them together gives me a headache!