Below is a picture of the notching/marking tool I mentioned in the chatroom a few nights ago. This tool is for marking a saw blade for new teeth after the old teeth have been ground off.
On the left it shows a thread gauge clamped to the end of the saw blade for the first 5 or 6 notches. From then on the file guide on the left slides in an already filed notch while the file on the right files another notch.
Templates could be made to be used in place of the thread gauge. That is what I intend to do for future saws that I retooth. A template would allow notches to begin at the very end of the blade. The thread gauge prevents this and requires notches in that area of the blade to be file in the opposite direction.
>By your fine photographic renderings I can see that it is set at a predetermined number of teeth per inch. What is the tpi for this particular model?
And thank you for posting this excellent hand tool. I would imagine that the style is much older than your example but I can see how this tool would be very useful.
And I think a traditional example of this tool could find service in my shop, I must talk to the blacksmith (Mr. Westover), he is quite busy with cash work, so my trade work comes up second.
To answer your question regarding the TPI....The TPI or "teeth per inch" is 10, in this case.... per the thread gauge but for a saw it is an 11 PPI, "points per inch". The number below the handle on your handsaws indicates the PPI, not TPI. You might find it interesting that the saw in the pictures is a 5PPI rip saw. What I am filing there are teeth on the top edge of the blade, set back about one inch from the toe end of the blade before the smaller rip teeth begin. There are about 3 inches of rip teeth at 11PPI. These teeth do what you do when you use the NIB on your saws. The smaller teeth makes it very easy to start a cut precisely where you want it. There is no set in these teeth because you only saw into the wood about a half inch or less.
You could easily make a tool similar to this one with the use of a couple pieces of hardwood with holes drilled and the files merely jambed into the holes like you would a file handle. I do alot of metal work so I tend to think in terms of using metal first. If I make another one, I'll use wood and make the back end shaped like a file handle with two holes in it.
Using a thread gauge allows you to file most any PPI. I laid out a blade for dovetail saw 16PPI only once using dykem and a scribe. That's all it took to determine there has to be an easier way. If you file alot of saws, you end up with alot of dull files laying around. I'm sure Mike W. can attest to that. This tool makes use of at least two of those dull files.
Sometimes the most simplest tool is the most useful.
the files on this particular notcher are one half inch apart, however, you might want them a little farther apart depending on how many teeth are on the thread gage. The tool in the picture is a prototype. When I make another one I'm going to use wood instead of the aluminum bar stock and I'll make the handle with two holes in it for the tangs of the two files.
>Using a thread gauge allows you to file most any PPI.
Surely the distance between your "follower" and your file must be an integer multiple of the distance between gullets, which means you need several different tools?
>Don't think so Bugbear. The TPI is determined by the template. Once gullets are started the tool can be repositioned into "patterned" teeth to fill in any gaps caused by the tool follower to file distance. The template only needs to be longer than the gap between the file and follower.At least thats how I understand it.:-)JR
Each and every gullet must be an integer multiple of teeth sizes from the other gullets. That's what (uniform) tooth spacing means.
But if the spacing between the "follower" file and cutter" file is NOT an integer multiple of the tooth size, a gullet will be cut at a distance from the "guide gullet" which is NOT a multiple of the tooth size.
>Ok...I'm working on it...Picture steam rolling out of my ears:-) I get the idea you speak of but I still think there is a manual workaround there somewhere.JR
There's always a workaround in handtools (<:). However, one may not be needed. I can't make out from Marv's first photo what the spacing is between the indexing file and the cutting file. But suppose he picked 1" even. And also suppose that he only works in even gullets per inch, e.g., 5 gullets per inch, 7 gullets per inch, 10 gullets per inch. And thirdly suppose that the screw thread gauge is in even threads per inch.
If these three things happen, then there will be no discontinuity when the indexing file leaves the thread gauge and starts indexing off the saw blade. 1" spacing of the files could be magic. In theory (<:).
