Thread: Handsaw hang angles.

Derek,

Isaac's analysis is interesting but I haven't come across an analysis that includes h, the height of the saw plate. Have I missed it?

Rob

Isaac makes a valid point regarding hang angle;

This principle being that, as the weight of a saw increases, the teeth “bite” more deeply into the wood, allowing a greater proportion of the sawyer’s thrust to be directed parallel to the toothline (and less of it downward) by lowering the hang angle of the handle.http://www.blackburntools.com/blog/f...f-hang-angles/

Stewie;

Stewie,

I agree that the mass in front of the handle has an effect. However, I still haven't found a discussion of the height of the saw plate (h), or is it the height of the center of force on the handle, relative to the toothline.

Rob

copied from the other thread https://www.woodworkforums.com/showth...43#post1899943

Originally Posted by derekcohen

Thanks Rob

An example of something more specific are the articles by Isaac Smith (Blackburn Tools). He descrives how he sets the hang angle to the cant of the saw plate ..

http://www.blackburntools.com/blog/i...ssion-of-hang/

On my recent mitre saw (in a mitre box), with a 16" long plate, the hang angle was 23 degrees. This encourages more of horizontal push, which is wanted in a mitre box, where downforce is unnecessary. 23 degrees is also recognised by some, such as Isaac, for tenon saws generally ... regardless of length?



http://www.blackburntools.com/blog/c...d-saw-handles/

Any thoughts?

Regards from Perth

Derek

hope I'm not stomping on toes ...

also copied from the other thread

Originally Posted by derekcohen

Stewie, you opened the topic ...



Regards from Perth

Derek

I think you're overlooking a couple of critical aspects.

every backsaw has an maximum depth of cut -- set I suggest by the clearance between the tooth line and handle less some measure, say 1/4 in

the maximum depth should be some multiple of the optimum depth of cut which will related to the typical furniture joint designed for cutting with the particular saw.

The "ideal" hang angle will then be related to the relative height of the sawyer, the height at which the work is held or clamped and the depth of the cut.
Relationships to the saw plate depth will be then be related back to these fundamentals

Originally Posted by ian

also copied from the other thread

Hi Ian. Can you supply any more clues. I am not sure of the point your trying to raise.

regards Stewie;

Hi Ian,

I haven't overlooked the other factors, I just didn't mention them. Of course all are important. The thrust of my comment was directed to the analysis Isaac did where h was defined/called out but not used. The rake angle, and all of the factors you mention, are connected to h as well. As Ron B. has said...

Cheers,
Rob

Originally Posted by ian

I think you're overlooking a couple of critical aspects.

every backsaw has an maximum depth of cut -- set I suggest by the clearance between the tooth line and handle less some measure, say 1/4 in

the maximum depth should be some multiple of the optimum depth of cut which will related to the typical furniture joint designed for cutting with the particular saw.

The "ideal" hang angle will then be related to the relative height of the sawyer, the height at which the work is held or clamped and the depth of the cut.
Relationships to the saw plate depth will be then be related back to these fundamentals

Hi Ian. You have raised some interesting thoughts to the discussion.

regards Stewie;

Hi Stewie

at the risk of stepping on some toes, I thought it would be worthwhile to repeat Derek's comments in this thread

Hi Ian. I dont think I was being unreasonable in asking Derek to open a separate thread on hang angles. Most saw makers for example will have a differing opinion as to where along the tooth line they like to see the extended index finger point too. If you take dovetail saws as an example, I personally dislike the higher hang angle Isaac prefers. That doesn't mean I devalue Isaac's opinion.

Stewie;

I agree.
I too thought it was a good idea.
I also thought it was worthwhile to copy Derek's two posts on the subject into this thread. Perhaps that was too presumptuous, in which case I apologise.

Hi Ian. I see no problem.

regards Stewie;

Historically there is little written evidence that gives modern saw makers a clear insight into the thought process of early saw makers. As a result. What we gain in knowledge the study of the early saw makers work, will vary according to how each individual modern saw maker is able to interpret that information. As an example; achieving a clear consensus on the best hang angles for each type of backsaw is going to be very difficult to tie down. IMO

regards Stewie;