Fret saw blade ?

[James Pallas]

I'm going to build a few small boxes. I thought I may try a fret saw on some dovetail work. I've either chopped or used a coping saw in the past. If you are a fret saw user what blades are you using for material up to 1/2". Thanks in advance.
Jim

[Jim Koepke]

Howdy Jim,

I bought a pack of these:

http://www.leevalley.com/us/wood/pag...884,42904&ap=1

Also bought a few others from LV, mostly the spiral blades but here is the root page:

http://www.leevalley.com/us/wood/pag...4&p=42904&ap=1

jtk

[James Pallas]

Thanks Jim Do you find the spiral blades useful? I would think they would be all over the place for dovetails. Probably would be fine for inlay work, I do some of that also but always use knives and carving tools.
Jim

[Patrick Chase]

I'm going to build a few small boxes. I thought I may try a fret saw on some dovetail work. I've either chopped or used a coping saw in the past. If you are a fret saw user what blades are you using for material up to 1/2". Thanks in advance.
Jim

#7 Pegas skip-tooth. It's the second-to-most-aggressive one in the set Jim recommended. I mostly use them because that's what Lee Marshall ships with the Knew Concepts fretsaw, and it worked so I stuck with it.

The big advantage to the spiral blades is that they cut omidirectionally so there's no minimum corner radius. The big disadvantage is that they're slow. In my experience you don't need the cornering ability of a spiral blade if you cut your dovetails with a western backsaw - The saw kerf will already be wide enough to allow you to start a conventional #7 blade fairly close to the desired angle in the starting corner (i.e. you won't have to start it oriented the same way as the kerf and then turn it through ~100 deg while cutting like you would with a coping saw), and from there you just cut in a straight line to the opposite corner. You might have to leave a little bit of additional wood in the starting corner, but that's super easy to clean with a chisel and not worth sacrificing cutting speed.

I could see the spiral blades being useful for that initial turn if you use an ultra-thin-kerf dozuki or similar to cut your DTs, though.

[Jim Koepke]

Do you find the spiral blades useful?

At first I used them a bit, but now I have gotten better with the regular blades. The spiral blade is almost like using a small round file.

jtk

[James Pallas]

Thank you Patrick and Jim. Very helpful. I ordered some blades and will try it out.
Jim

[Andrew Pitonyak]

#7 Pegas skip-tooth

I also use a #7 skip-tooth and then I cut very close to the line, closer than I think you can with the spiral blade so clean-up is very fast.

I need to be careful when cutting thicker material especially since I sometimes break blades if I am not careful; for example, 3/4" oak it is not uncommon for me to break a blade.

[Derek Cohen]

I use Pegasus #7.

A tip (extract from an article on through dovetails: http://www.inthewoodshop.com/Furnitu...ovetails3.html ) ...





The waste is now removed with a fretsaw. I aim to saw along the top of the chisel wall. This should leave about 1-2mm of waste above the line.


As with the saw, the fretsaw must be held as lightly as possible. Never force the cut. Let the saw do the work. A way of determining how you are doing is to watch the blade – it should hardly deflect. You should be rewarded with a fairly straight saw cut.


Regards from Perth

Derek

[James Pallas]

Thanks Derek, I have been reading your page for quite some time now. Very good info on it. I have cut a lot of dovetails just not with a fret saw. I don't try for showstoppers just good journeyman work. Just thought a fret saw would work a little better in lighter material. Ordered some blades, 5's and 7's to give it a try.
Jim

[Patrick Chase]

The waste is now removed with a fretsaw. I aim to saw along the top of the chisel wall. This should leave about 1-2mm of waste above the line.

A couple things that are visible in Derek's photo but may not be obvious if you don't know what to look for:

- He started the fretsaw cut almost straight across and therefore perpendicular to the kerf. This is what I was trying to describe above - even with a conventional blade like the Pegas #7 you can turn most if not all of that corner by simply rotating the blade in the kerf left by a western-style backsaw before you start to cut (not so much in a dozuki's kerf though).

- He's rotated the blade 45 deg clockwise (as seen from the user's end of the saw) to keep the sawframe above the end of the workpiece both when sliding the blade vertically down the existing kerf and then when cutting horizontally. That's a handy feature of the Knew Concepts fretsaws, that isn't present on many jeweler's saws or fretsaws.

I don't bother cutting a chisel wall on the baseline - I just aim 1/32" to 1/16" above the baseline from my gauge. That saves me some up-front time but forces me to be more careful when paring since my baseline isn't as solid as Derek's. In particular it means that I can't pare directly to the baseline until there's very little material left above it, or else the chisel's bevel would push it below the baseline (having a chisel wall prevents that to some degree). I suspect this is a case where different people will find different optima.

[Andrew Pitonyak]

I use Pegasus #7.

A tip (extract from an article on through dovetails: http://www.inthewoodshop.com/Furnitu...ovetails3.html ) ...

Derek, the "screws" used to hold the blade, they look like they are made of brass.... These are not standard are they? My saw has plastic. Are they stock? Did you make them, buy them? I am curious (since I also own a knew concepts saw).

[Derek Cohen]

Andrew, these are now standard (a few years now). Contact Lee at Knew Concepts. They are anodised aluminium. I prefer them to the plastic pointy ones.

Regards from Perth

Derek

[george wilson]

Spiral blades are an abomination,and should not be used by anyone who aspires to develop decent skills with a fret saw.

[Andrew Pitonyak]

Thanks, I will contact them. The plastic ones work, but...

[James Pallas]

Spiral blades are an abomination,and should not be used by anyone who aspires to develop decent skills with a fret saw.

I love your approach George! All the years of experience and the fact that I can be sure you have actually tried spiral blades makes it a fact to me. If I ever pick up a fret saw with a spiral blade your advice will surely come to mind. Keep telling it like it is and many will listen. You give me a big laugh almost everyday. Thank you for your expertise.
Jim