A couple of Disston #4 type tennon saws nearing completion.

[rob streeper]

This thread unites my previous posts concerning bushing/bearing reinforced saw bolt holes, vacuum infused handles and my taper grinding posts.
These saws are near completed. All that remains is a little detail work, buffing and a final cleaning. Both saws have resin infused handles and the saw bolt holes are bushed with bronze bearings. The brass backed saw has a 0.015" plate toothed 15t.p.i.

303790

303789

The stainless backed saw has a taper ground 0.025" plate toothed 13 t.p.i.

303787

303788

Cheers,
Rob

[fields]

Love the nice crisp lines, good job!

[rob streeper]

Love the nice crisp lines, good job!

Thanks. There is still some clean up to do and as these have minor cosmetic defects I will keep them for shop use.

[planemaker]

Very nice work Rob. You have developed your own unique style of handle shape. Kudos for that.

Stewie;

[rob streeper]

You have developed your own unique style of handle shape. .

Stewie;

Thanks Stewie, The lambs tongue is still a bit of a struggle. I was thinking of the movie A Christmas Story where the little kid get's his tongue frozen to the metal pole while I was working on them. http://www.youtube.com/watch?v=_RgCbcT8eEU

Cheers,
Rob

[artme]

Just doesn't seem right that one person is blessed with such skills and artistry!:no:

Beautifully done!!:2tsup::2tsup::2tsup:

[rob streeper]

Just doesn't seem right that one person is blessed with such skills and artistry!:no:

Beautifully done!!:2tsup::2tsup::2tsup:

Thanks but they're not that nice. There are a lot of little things that I want to do better. They do work well though.

[rob streeper]

A couple shots of the finished stainless backed saw.

304143304144

[McDrew]

Nice saws. I'm jealous you have access to the parts to make your own saws. At this point in time I am searching all over for the spring steel for saw blanks and brass backs. For what used to be a big steel nation, it's embarrassingly difficult to find the right spring steel.

I've made one handle, I didn't attempt the lambs tongue because my tools are very limited. Good work.

[rob streeper]

Nice saws. I'm jealous you have access to the parts to make your own saws. At this point in time I am searching all over for the spring steel for saw blanks and brass backs. For what used to be a big steel nation, it's embarrassingly difficult to find the right spring steel.

I've made one handle, I didn't attempt the lambs tongue because my tools are very limited. Good work.

Thanks McDrew,

It was a bit of a struggle to put together all of the pieces. I sourced spring steel on Ebay, search for 'blued spring steel', '1095 steel', 'blued and tempered' and so on. If you can wait a while some will turn up. I am looking into other 10XX steels including 1074 and 1080/84. Both can be hardened to Rc 60+ and are apparently easier to heat treat than is 1095. I am working on the heat treating angle because I recently came into an oven and a hardness tester. I surveyed the saws I have and the hardest came out with Rc of about 43, one came out with Rc of 11! The reading is surely anomalous because the Rc tester becomes inaccurate below Rc 20 but it definitely means the saw plate is soft and it explains why this new saw from one of the custom makers is a bit of a dog. I tested an old Disston D-8 (~1920's) and it was Rc 52. I have read elsewhere that Disston saws were hardened to Rc 52. I have a couple others that I will test later in the week.
I make my backs and I have a local source for the screws that is reasonable. Look up somebody who has an automatic screw machine and is willing to do small lots.

Cheers,
Rob

[Isaac S]

I surveyed the saws I have and the hardest came out with Rc of about 43, one came out with Rc of 11! The reading is surely anomalous because the Rc tester becomes inaccurate below Rc 20 but it definitely means the saw plate is soft and it explains why this new saw from one of the custom makers is a bit of a dog. I tested an old Disston D-8 (~1920's) and it was Rc 52. I have read elsewhere that Disston saws were hardened to Rc 52. I have a couple others that I will test later in the week.

It's been a while since I slept through my materials class, and this is outside of my field, but Rockwell hardness testing does not always work well on thin materials. I suspect that in the thicknesses and hardnesses that most of our backsaw blades are made in, a typical Rockwell hardness tester is not a reliable instrument.

This document (http://www.instron.us/wa/library/streamfile.aspx?doc=1154) from Instron has some guidelines for testing materials, and goes into pretty good detail. Of particular interest is the table below (Table 5 on page 13), which gives the minimum hardnesses far a given thickness that can be reliably measured with a Rockwell test.

304475

For steel that is 0.040 inches thick, hardnesses of RC20 and greater can be safely/reliably measured. Most of the D-8's are around this thickness, if I am not mistaken, so your test on that saw may be accurate (assuming the tester is calibrated correctly).

If you want to measure the hardness of 0.025 inch thick steel, the minimum recommended hardness is around RC66, much harder than any saw plate would be. If you want to measure plate that is 0.020" or less, then you are basically looking out of luck with a standard Rockwell test in the hardness range you are looking at. I'm not sure of the thickness of the plate you tested at RC11, but this could be an explanation for the low readings.

This all assumes you are using a Rockwell tester with a Brale indenter; if you are using some other tester, then the above doesn't apply.

And, of course, these are only guidelines, so make of it what you will.

[McDrew]

You have some interesting projects going on. I am interested in how you achieve your vacuum infusion.

The one UK supplier that says they ship "worldwide", finally got back to me and said their courier no longer delivers to south East Asia or Australia. I'll keep an eye out on eBay, thanks for the heads up.

[rob streeper]

I suspect that in the thicknesses and hardnesses that most of our backsaw blades are made in, a typical Rockwell hardness tester is not a reliable instrument.




For steel that is 0.040 inches thick, hardnesses of RC20 and greater can be safely/reliably measured. Most of the D-8's are around this thickness, if I am not mistaken, so your test on that saw may be accurate (assuming the tester is calibrated correctly).



Hi Isaac,

My earlier post was brief and incomplete because of time considerations. Here are some more details.

Yes, I am using Rockwell C with the 120 degree diamond. Authorities differ on minimum thicknesses, some say the material must be at least three times thicker than the indentation diameter and some say ten times thicker. I know the chart you posted and use it as a guide.
I calibrated my instrument using three hardness blocks ranging from Rc 27.2 to Rc 62.2. I have a slight deviation of 0.5 Rc units over that range with the low end reading slightly high and the high end slightly low. My midpoint block is Rc 46.1 and the tester gives back that value to the limit of my ability to read the scale. The tester is Chinese and like many of their industrial products it is rough cosmetically but functionally excellent. I spent two full days disassembling, cleaning, reassembling and calibrating it.

I don't yet have a superficial hardness tester but I have my eye out for a deal.

In the following discussions I will use an asterisk next to those Rc values that are outside of the acceptable parameters for such testing by Rc*.

The Disston D-8 I measured was 0.032" thick which for Rc 52 is reported to give a valid reading, any thinner or softer and it does not.

The saw that came up with an anomalous low reading of Rc* 11 (Rc loses validity below about 20 as well) was a 0.030" thickness saw. Outside of the acceptable thickness range for Rc but not by much and given the huge Rc* difference I am pretty confident it is soft. I couldn't believe it at first either so I repeated the test, five times in the area under the handle (Perhaps the maker annealed this area, I don't know) and twice on two points at the tooth line. All readings were consistent and low.

The values measured for thinner materials will be lower, and in a non-linear fashion, due to sideways flow of the thin material when using the Rc scale. However, for materials of the same thickness it is possible to tell harder from softer plates. For the thinner plate saws I compared to 0.015" 1095 that I have which is reported by the manufacturer to be Rc ~ 48-52 and on my tester it gives an indicated Rc* of 42. I have a total of five 0.015" plate saws from two different manufacturers. I have one saw from manufacturer #1 and four saws from manufacturer #2. The plate from manufacturer #1 gives me the same reading as I observed for my 1095 reference standard, Rc* 42. Those from manufacturer #2 all gave readings of Rc* 35. Thus I conclude that the saws from manufacturer # 2 are softer than that from manufacturer #1. Not by 7 Rc units of course because I know that the scale in this region is non linear.

Since there are no systematic studies of this issue presented on this site I will post my results. I will not of course identify any manufacturers.

Cheers,
Rob

[Sawdust Maker]

Nice saws

what are the tote's made from?

[rob streeper]

Thanks for the compliment.
These were made from a piece of walnut I had laying around. Not the best quality wood - it had a long hidden fracture. That is why the stainless backed saw lacks one of the horns on the top.

I started the handles to investigate two different techniques. First was vacuum infusion of resin to strengthen wood. In summary, it made the wood harder, tougher and somewhat more difficult to sand. No problems with rasping/filing or with finishing. Inexpensive and simple to do too.

The second effort was to investigate the use of bushings in the handle to support the saw screws, minimize play between the saw plate and the handle and diminish or eliminate the need to periodically tighten the screws. The technique works on all three counts. I originally intended to test these handles to destruction but as I progressed I decided that I liked them so no smashing.

I have yet to organize my pictures and text concluding the two threads on these handles because I am now working on heat treating and hardness testing.

Cheers,
Rob

[rob streeper]

You have some interesting projects going on. I am interested in how you achieve your vacuum infusion.

The one UK supplier that says they ship "worldwide", finally got back to me and said their courier no longer delivers to south East Asia or Australia. I'll keep an eye out on eBay, thanks for the heads up.

McDrew,

The infusion is super easy to do. Just be careful with the vacuum stuff and flammable solvents as I detailed in the other thread. The resin tends to gum up sand paper easily and it takes a full week to dry when it is cool. Otherwise the treatment does not interfere with finishing or shaping and it definitely makes the handle stronger and tougher.

Cheers,
Rob

[rob streeper]

Finally getting back to the saws. Here are some in-process pic's of #12. The saw plate is 13ppi, 0.015" at the tooth line and taper ground to 0.013" at the bottom of the back. I decided to use my bushed saw bolt fit up on this one. The stock is Brazilian cherry. I intended to set this saw up with a stainless back but it seemed too light and tended to chatter so I switched to 1/8" folded brass. Now it's just right and grips the very flexible plate with authority. Much more fitting up to be done of course.

330120330118330119

[planemaker]

Looks good Rob. Great to hear your back into saw making again. :2tsup:

Stewie;

[Simplicity]

Looks great Rob
One question did you fold the back yourself or were they brought

[RayG]

Hi Rob,

Nice looking saw, and incorporationg some very clever and very innovative ideas, I like the taper ground 15 thou thin plate..

I'm going to do some experiments along those lines and see how it stands up. How have you found the thin plate so far?

Ray

[rob streeper]

Looks great Rob
One question did you fold the back yourself or were they brought

I did the back using alloy 260. I think that I want to set it deeper in the handle.

[rob streeper]

Hi Rob,

Nice looking saw, and incorporationg some very clever and very innovative ideas, I like the taper ground 15 thou thin plate..

I'm going to do some experiments along those lines and see how it stands up. How have you found the thin plate so far?

Ray

The thin plates are fine so far, I haven't tried to test one to failure yet. I made the test cuts in wet pressure treated pine using a degree of force I would call aggressive, no problems. I have found however that they stay sharp longer if filed rip with about a 12 degree rake and a very light set. I'm going to try cryogenic hardening on this plate.

[rob streeper]

My business manager just returned with a bunch of backs, partially completed saws and finished saws that went out for laser marking. Here are some pictures of some of the saws I've previously posted here with markings.


330217330219
330220330221
330222330218

[rob streeper]

Before I finish this one up I wanted to do some more testing. I clamped up a 2" X 6" scrap of wet treated lumber and cut aggressively down to the back a number of times. Each cut took 4 to 6 strokes.

330301

Cuts nicely if I do my part and start the kerf straight.

330303

And there isn't much tear-out either.

330302

However, I gotta fix this.

330304

I'll split the story here and start a new thread discussing the tensioning of the saw plate. Look here: http://www.woodworkforums.com/showthread.php?t=189765 to see the saw tensioning.

[rob streeper]

Here's #14 (I called it #12 above) just before completion. I have to true up some radii on the transitions, sand a few places and complete the finish application.

330677

[Simplicity]

Nice one there Rob
Looks great well done
Matt

[rob streeper]

Nice one there Rob
Looks great well done
Matt

Thanks Matt.

The saw making thread seems pretty quiet, everybody on vacation?

Cheers,
Rob

[rob streeper]

Last night I got to thinking about #14. Specifically about this.


330823


What do those teeth do that are below the cheeks of the handle?

I'm usually squarely in the BOSS (Boring Old Square Saws) camp when it comes to saw design. What can I say, I like traditional designs and design elements. Ask anybody who knows me and they'll tell you I have a strong case of anartismia (artistic deficiency syndrome). For me square corners are easier to understand but nonetheless I'll give the curvy plate profile thing a shot.

First step is to decide how much of the tooth line to remove. Using a machinists square I drew tangents off of the front and bottom of the cheeks like so.

330822


Note that I set this handle up with bushings on the saw bolts. It adds somewhat to the cost and time but the result is an extremely tight fit up of the saw bolt shanks to the saw plate and handle. Saws I do up this way are so well fitted that even if the saw bolts are loose there is no movement perceptible between the saw plate and the handle. Will it last 100 years? No idea but none of us will be around to complain.


330820

Next I pulled off the handle and dropped a line from the bottom tangent of the cheek to the tooth line using a French curve.

330821

I think I'll use the curve to the right.

Now to the grinding. Here is the agent of destruction. 60 grit ceramic belt.

330828


Pains me to cut away such a nice square corner.


330827

Once the bulk of the steel is gone I moved on to 120 grit aluminum oxide.

330826


Got it cut back reasonably close to the line.

330825

And on to hand filing.

330824

I refitted the plate to the stock and put in a couple saw bolts to hold it in place. The steel stands a little proud of the cheeks back at the juncture with the lambs-tongue.

330834

So very carefully take the area down some.


330833

Next I de-burred and dressed the plate. First with a 120 grit 3M DiaPad.


330819

These things are great stuff. Cut steel like butter. They recommend lubrication so I use this.

330830

Light oil and prevents rust too.

Follow up with 280 grit Wet & Dry also lubricated with the Rust Oleum product.

330832

Final visual check.


330829

Looks good, now to brush up the teeth and complete the finishing of the stock. More later.

[rob streeper]

Here it is fitted up with the handle partially finished.

330839

[Simplicity]

Hi Rob
Can't speak for everyone else.
I know Stewi has been busy in the plane making camp again and there looking great.
But I haven't done a saw for ages due to time and lack of saw plate and backs. And a other million things going on.
Tho yours definitely inspire me to get back to it.
Your post in regard to tensioning the blade made for some interesting reading .
I'm still getting to grips with what your talking about.
Tho that's no fault on your behalf just me.
I've also been keeping an eye out on your rasp making activities big well done there.
If you could send me a dozen when done that would be great and I will review them ,abuse them ,then send that back with a full report of course.
In regard to you hacking a chunk out of the rear of your last creation.
That looks great now hit it with some files on the back lol.
As you know I'm not politically correct.
If it works as intended and your happy .
End of story in my book.
I'm not one to stand in the way of development.
Keep up the good work.
Matt
Ps I'm still thinking about my upside down handle idea.

[rob streeper]

Hi Matt,

I was wondering where that thread with the USD handle wandered off to.

Rob

[Simplicity]

Its in research and development stage lol
Matt

[Bushmiller]

Rob

Those saws are just marvelous and I was most interested by two aspects and one query. To get the query out of the way first, was the placement of the split nut on the left hand side of the saw in post #25 deliberate? Conventionally they are on the other side, of course.

I thought you might be interested to see the heel shape of the mitre saws as, while not as extreme as your modification, they do reflect your thinking. These are Simonds No.95s from the 1920 era. (Ahem..One has been cut down, modified or bastardised if you prefer.)

330998330999

The other point was your bush to minimise tote movement. As far as I am aware the only manufacturer to address this issue was Disston with their D-95, athough they used a quality plastic and not timber. The handle was two piece with a square locking washer. The holes in the plate were huge to accommodate the raised plastic.

331001331002331000

You may be the only other saw maker to attempt to prevent movement and your totes are so superior to Disston's :2tsup:.

Regards
Paul

[rob streeper]

Paul,

Thanks for your kind words. The saw bolts in the pictures contained in post 25 are reversed, by accident. Too many distractions and tiredness.

As to the plate outline, I was thinking of this saw.

331060331059

It is made by Disston and the etch is Goodell Pratt.

The bushing effort was motivated primarily by my desire to avoid burring saw screws by repeated tightening due to the shrinking and swelling of the handle induced by fluctuations in ambient conditions. So far it works fine. Once the bolts are tightened down I have found no further need for tightening.

Cheers,
Rob

[batman3000]

Call it a left handed saw.

[rob streeper]

Call it a left handed saw.

I could but I made it up to be a right handed saw. I canted the handle slightly and tapered the thickness of grip section from bottom to top. I'll try to post some more detailed pictures if I can get my camera to focus on them adequately.

Here's a prettier shot.

331149

[RayG]

Very nice Rob, I liked the evolution of the design, and I think the shaping of the heel of the plate looks just right. :2tsup:

Ray

[rob streeper]

Here's #8 completed.

332624

And #14.


332625