Thread: Latest backsaw handle design.

Very nice proportions on that one.
How big a balde is it for?

14 inch; 3 1/2 inch below the spine; 10 tpi; 10 degree rake angle; no fleam; 0.025 gauge saw plate.

regards Stewie;

That's very nice Stewie.

Pete.

Nice handle

On another forum I received this question regarding this backsaw handle.

Originally Posted by Rich Greinert

Stewie, in the photo there is a notch at the very bottom of the handle. Does the plate extend that far? What is the purpose of this cut-out?
Very nice work!

The following was my reply.

Hi Rich. The notch allows the bottom rail to flex during seasoning wood movement. Without that notch there is a likelyhood the bottom rail would fracture some time in the future, most likely at a point further up along the bottom rail at or near the curvature of the lambs tongue where there is vulnerability due to a lack of long grain structural strength within that area. Hope that helps answer your question.

regards Stewie;

Originally Posted by planemaker

On another forum I received this question regarding this backsaw handle.



The following was my reply.

Hi Rich. The notch allows the bottom rail to flex during seasoning wood movement. Without that notch there is a likelyhood the bottom rail would fracture some time in the future, most likely at a point further up along the bottom rail at or near the curvature of the lambs tongue where there is vulnerability due to a lack of long grain structural strength within that area. Hope that helps answer your question.

regards Stewie;

http://www.academia.edu/9772626/DESIGN_OF_NOTCHED_WOOD_BEAMS

http://www.ewp.rpi.edu/hartford/~ern...Roark-Ch06.pdf

I've always understood that the notch or clip was a design element that provides a nice transition between the curved cross section of the lamb's tongue and the straight cross section of the lower horn.

Surely the presence of the notch would only make the handle weaker?
I'm not about to test any saws to destruction to prove or disprove this!

Originally Posted by planemaker

On another forum I received this question regarding this backsaw handle.



The following was my reply.

Hi Rich. The notch allows the bottom rail to flex during seasoning wood movement. Without that notch there is a likelyhood the bottom rail would fracture some time in the future, most likely at a point further up along the bottom rail at or near the curvature of the lambs tongue where there is vulnerability due to a lack of long grain structural strength within that area. Hope that helps answer your question.

regards Stewie;

Have a look at the photo of the Kenyon backsaw handle submitted by Pedder. Note where the fracture occurred on the bottom rail.

Also, take note of the sharp change of direction from the bottom rail to the lambs tongue.

http://www.ukworkshop.co.uk/forums/t...aw-t90319.html

Stewie;

Originally Posted by planemaker

Have a look at the photo of the Kenyon backsaw handle submitted by Pedder. Note where the fracture occurred on the bottom rail.

Also, take note of the sharp change of direction from the bottom rail to the lambs tongue.

http://www.ukworkshop.co.uk/forums/t...aw-t90319.html

Stewie;

Not surprising that the Kenyon saw handle you point to fractured where it did given that the grain axis will generally trend from the back through to the top horn. The grain at the point of breakage is at about 90^o to the bottom rail of the lambs tongue and parallel to the grain axis, reducing the inter-lamina contact area to a minimum thus creating an extremely weak point. Such a structure is weak in much the same way as if one were to create a dowel with it's long axis perpendicular to the grain of the wood. Nonetheless, the step does look nice, one just needs to be careful.

Work on the saw plate assembly is now complete. The handle has received its 4th coat of garnet shellac. 2 more coats remaining. After the last coat of shellac I allow 5 days for the shellac to further harden before I work the surface down with a cutting paste, then buff to a shine with a powered mop.

Stewie;

Very nice work Stewie. Are you following the usual French polishing techniques?

P.S. Also, interesting how stylistic features tend to divide opinions in the thread you linked.

Originally Posted by rob streeper

Very nice work Stewie. Are you following the usual French polishing techniques?

P.S. Also, interesting how stylistic features tend to divide opinions in the thread you linked.

Hi Rob. No. Traditional French polishing is much more suited to flat surface work. Not saw handles. I use a modified technique.

I agree with you on that linked thread. Its unfortunately become a divisive discussion.

Stewie;

Originally Posted by planemaker

Hi Rob. No. Traditional French polishing is much more suited to flat surface work. Not saw handles. I use a modified technique.

I agree with you on that linked thread. Its unfortunately become a divisive discussion.

Stewie;

Another example of https://en.wikipedia.org/wiki/Sayre%27s_law

Originally Posted by rob streeper

Another example of https://en.wikipedia.org/wiki/Sayre%27s_law

https://www.google.com.au/search?q=g...Q&ved=0CDoQsAQ