Thread: The history of taper grinding of saw blades

Henry Disston, consummate marketer that he was, extolled the virtues of his taper ground saws. Unfortunately there's little information available these days describing how the grinding was done. Further, there is scant information on the date of introduction of taper ground saws into commerce.

As part of my study of the hardness of saw blades over time (Hardening of sawplates) and my investigations of a couple of early Disston backsaws bearing taper ground blades (Disston split nut backsaw - is it a No. 77 or ?) I became interested in how and when Disston began producing tapered blades. I have a couple of handsaws from the 1840-1850 period that are not tapered. Another member has a similar saw that is also not tapered (My First Ebay Purchase - Henry Disston at post #3).

I've found that the earliest available Disston catalogs date from the mid-1870's, by which time tapered plates were listed.

Patents are nice because they are permanent records. They don't capture trade secrets or common knowledge. The patent literature of the 19th century is also limited in that little or no reference is made to foreign patents. The US patent literature can tell us something about how American saw makers were developing manufacturing techniques and these patents give us good dates on which they patented various technological improvements. Thus I dove into the patent literature.

The earliest US patent I've found regarding the intentional profile grinding of saw plates to afford a functional advantage is this from 1851 describing a veneer sawing method and machine.

US8022 Resawing machine discussing tapered and bulged circular saw blades, Crosby, April 8, 1851.jpgUS8022 Resawing machine discussing tapered and bulged circular saw blades, Crosby, April 8, 1851.jpg


Not dealing directly with handsaws of course but it does bring on the concept of altering the profile of a saw blade by grinding.

The first patent to discuss handsaw blade grinding comes along in 1856.


US16223 Grinding Metal, Andrews, December 16, 1856_Page_1.jpg

US16223 Grinding Metal, Andrews, December 16, 1856_Page_2.jpg
US16223 Grinding Metal, Andrews, December 16, 1856_Page_3.jpgUS16223 Grinding Metal, Andrews, December 16, 1856_Page_4.jpg

These two appear at this point to constitute the entirety of the patented work in this area for the period 1850-1859.

The first Disston patent on the subject appeared in June of 1860.

US28742 Machine for grinding saws, Dougherty, June 19, 1860_Page_1.jpgUS28742 Machine for grinding saws, Dougherty, June 19, 1860_Page_2.jpgUS28742 Machine for grinding saws, Dougherty, June 19, 1860_Page_3.jpg



This was followed shortly by H. Disston himself in August.

US29680 Machine for Grinding Saws, H. Disston, August 21, 1860_Page_1.jpgUS29680 Machine for Grinding Saws, H. Disston, August 21, 1860_Page_2.jpgUS29680 Machine for Grinding Saws, H. Disston, August 21, 1860_Page_3.jpg


Dougherty appears again in September of 1860.US30130 Machine for Grinding Saws, Dougherty, September 25. 1860_Page_1.jpgUS30130 Machine for Grinding Saws, Dougherty, September 25. 1860_Page_2.jpgUS30130 Machine for Grinding Saws, Dougherty, September 25. 1860_Page_3.jpg


At this time apparently patents didn't list assignments but if you compare the witnesses you can see that all are related to Disston.

This body of work coincides nicely with the 1860-1865 production taper ground Pre-77 saw I discussed here (Disston split nut backsaw - is it a No. 77 or ?) beginning at post #1.

The 1860's saw a number of additional patents granted for saw grinding machines.



US41,419, Baker, February 1864. This machine isn't attributable to Baker. Baker was apparently designing machines for a number of companies in the 1860's and 70's.

US41419 Improvement in Grinding Handsaws, Baker, February 1864_Page_1.jpg

US41419 Improvement in Grinding Handsaws, Baker, February 1864_Page_2.jpg

US41419 Improvement in Grinding Handsaws, Baker, February 1864_Page_3.jpg

US41419 Improvement in Grinding Handsaws, Baker, February 1864_Page_4.jpg

US41419 Improvement in Grinding Handsaws, Baker, February 1864_Page_5.jpg

US46,843, Baker, March 1865

US46843 Improved saw grinding machine, Baker, March 14 1865_Page_1.jpg

US46843 Improved saw grinding machine, Baker, March 14 1865_Page_2.jpgUS46843 Improved saw grinding machine, Baker, March 14 1865_Page_3.jpg


US53,725 by Baker, April 1866.

US53725, Improvements in grinding saws, Baker, April 1866_Page_1.jpg

US53725, Improvements in grinding saws, Baker, April 1866_Page_2.jpg

US53725, Improvements in grinding saws, Baker, April 1866_Page_3.jpg

US53725, Improvements in grinding saws, Baker, April 1866_Page_4.jpg

US 54,813, by Baker, May 1866.

US54813 Grinding Saws, Baker, May 15, 1866_Page_1.jpgUS54813 Grinding Saws, Baker, May 15, 1866_Page_2.jpgUS54813 Grinding Saws, Baker, May 15, 1866_Page_3.jpg

US86,443, Baker, October 1868

US83443, Improvement in saw grinding machines, Baker, October 1868_Page_1.jpg

US83443, Improvement in saw grinding machines, Baker, October 1868_Page_2.jpg

Additional patents include

US30,209, Custer, October 1860
US44,903, Weaver, November 1864

The 1870's were also a productive time for the field with the appearance of these patents.

US106,071, Mefford, August 1870
US108,755, Gardner, November 1870
US111,147, Piper, January 1871
US111,619, Disston and Hill, February 1871 *
US123,945, Shoemaker, February 1872 *
The skew back D8 patent, US167,996, Disston, September 1875 *
USRE7,595, Bevan, April 1877 *

The 1880's

US269,729, Simonds, December 1882
US315,663, Richardson, April 1885 - an extreme evolution where a triangular hole is cut in the saw blade.
US346,565, Simonds, August 1886 relating to bandsaws.

The 1890's

US440,253, Prouty, November 1890
US593,907, Prouty, November 1897

The 1900's

US643,914, Shaw, February 1900, taper grinding of trowels
US671,451, Prouty, April 1901

* = Disston patents

There's been a slow trickle of saw grinding/beveling patents up to the present day.

The concept of ground saw blades was introduced by Crosby in 1851 but little additional work, only Andrews in 1856, occurred prior to the summer of 1860. The flurry of patent activity that began in the early 1860's and ran into the late 1870's suggests that the technology and machinery for accomplishing taper grinding on an industrial scale was introduced circa 1860 or so and was largely perfected by the mid 1870's.

This trend of development is likely the reason that my 1840/1850 era Disston handsaws are not taper ground but the 1860-1865 Pre-77 backsaw is tapered. Disstons patents in the 1850's dealt primarily with innovations in saw design, such as the combination of ruler, square level and scribe into the No. 43
saw.

Here are the PDF's of the above that aren't presented in the posts.

US44903, Grinding and Polishing Saws, Weaver, November 1, 1864.pdf
US30209 Rotary Saw Grinding and Polishing Machine, Custer, October 2, 1860.pdf
US108775 Improvement in machines for grindign saw blades, Gardner, November 1, 1870.pdf
US269729 Machine for and method of grinding thin back cross cut saws December 26, 1882.pdf
US315663 Saw with triangular opening in blade, Richardson April 14, 1885.pdf
US111147 Grinding Handsaws, Piper, January 24, 1871.pdf
US123945 Improvement in Saw Grinding Machines, Shoemaker, February 20, 1872.pdf

Thanks Rob for all that research. It must have been very time consuming. Disston, in particular, was renowned for taking out patents at the drop of a hat.

Regards
Paul

Paul,

Extracting this information wasn't too bad, I find computer searches to be pretty easy.

Disston created what's now known as a 'patent thicket', i.e. make a bunch of patents, all more or less related to a single subject, so that any challenger must sue all of the patents with consequent increases in costs. This stratagem tends to deter those who might be marginally infringed and infringers.

The patents, combined with a marketing program incorporating a fair percentage of plausible lies, probably kept many of his 19th century competitors tied in knots.

Regards,
Rob

Handsaw taper grinding patents by decade 092616a.jpg

I interpret this pattern of patenting related to handsaw blade grinding machines as indicating that this technology was pretty much mature by 1890. These machines were only being introduced in the United States in the late 1850's and early 1860's. The patents after WW1 appear to be primarily related to the introduction of electric motors to saw grinding machines. Thus, US made handsaws made prior to about 1860 generally will not have taper ground blades and those made after will.

Going back to the available company materials we have this photo. Taken from (Online Reference of Disston Saws -- Keystone Saw Works).

Disston works grinding.JPG

This may show the drive side of the Baker 1864 grinding machine. Unfortunately there isn't enough detail visible to be sure.

This photo entitled "Polishing" shows a machine that looks very much like the machine shown in the Bevan 1877 patent.

Disston works polishing picture.JPG

Rob

I'm not sure if I have posted these links before of a series of short videos of the Disston plant in operation. The quality is poor, the lighting is worse, but probably authentic and all quite interesting. I particularly was interested to see how they polished the saw handles.

Disston stock video footage and royalty free HD video clips and photos.(page 1).


There are five videos in this series.

Regards
Paul

Thanks Paul, I remember having seen those previously on the site but had forgotten where they were located. Obviously the blade grinding machine evolved even further during the 20th century but I guess Disston didn't see the point in continuing to patent or perhaps further patenting wasn't possible because the state of the art hand advanced so much in the public domain that something like the pictured grinder would fail the obviousness or inventive step tests.

Regards,
Rob

This wizened old saw showed up today.

1860-1865 handsaw 002.jpg

It has an 1860-65 medallion.

1860-1865 handsaw 001.jpg


And, consistent with my hypothesis, it is taper ground. The plate is 0.035" thick at the toothline and 0.027" at the back midway down to the toe. It also has the 7/16" head and nut diameter saw bolt in the number 1 position.

Rob

That's a fairly sound saw for that vintage.

Regards
Paul

I'm planning to clean it this weekend. It's seen a little misuse, tar on the teeth.

Great thread. I also recall seeing a photo by the river near the Disston factory with a bank made of discarded grinding stones. I see if I can find it.

Any thoughts on what the ideal grinding set up is?

Found some pics of the river bank stones in this thread on tapered daws here:
WoodworkersZone - Woodworking Forums - View Single Post - Taper ground plates?