Thread: Disston D-8 replica

I assume that:

Machine tensioning would have been done like here:
http://www.carbideprocessors.com/pag...saw-plate.html

Manual tensioning was done like Bob Smalser describes here:
http://www.wkfinetools.com/tRestore/...rSawBlade1.asp

Interesting how Bob refers to the implied tensioning from using the retoother.

Originally Posted by hiroller

I assume that:

Machine tensioning would have been done like here:
http://www.carbideprocessors.com/pag...saw-plate.html

Manual tensioning was done like Bob Smalser describes here:
http://www.wkfinetools.com/tRestore/...rSawBlade1.asp

Interesting how Bob refers to the implied tensioning from using the retoother.

Thanks for the links. Very interesting. I'm not going to set up a rolling mill but I have anvils and hammers.

tensioning the saw plate;

British Saws & Saw Makers from c1660; Simon Barley; published: Oct. 2014; Chapter 1; page 16; Making a saw; Smithing;

The saw plate might at this stage to the uneducated eye look flat, but it contained multiple and almost invisible irregularities which the trade called "fast and loose". These were corrected with a saw makers hammer that had two faces at right angles to one another and which produced the marks shown in Figure 1.14. The sheet also had to be hammered to produce stretching of the edge and hence "tension", in order to increase its ability to return to straightness when bent. Flatness and tensioning were achieved by the smith's hammering in one place after another, and on both sides, constantly checking for the right result using a saw makers straightedge (Figure 1.13), a strip of steel with a fractional concave edge.

The book details "tensioning the saw plate" as being only at stage 6 of the whole process. Stage 9 discusses Stiffening the saw plate;

Although there is no mention of this stage in the statement of prices, it appears to have always been part of the manufacturing process in the Sheffield saw industry. It involved heating the saw plate up to a fairly cool red heat, thereby restoring the flexibility that had been diminished by rubbing and blocking. There are indications in one manufacturers advertising material from the 1970s that stiffening was reserved for the best of their four qualities of handsaw. A stiffening trough was also referred to in the Wilson saw stock inventory of 1774, but there is no other information to enable us to know how or what stage it might have been used at that time. In an account of saw manufacturing at Spear & Jackson's works in 1861, stiffening was described as coming after setting.

I have three Disston hand saws that are in pretty fair condition. I decided to map the thickness profile of each saw plate. I measured at half inch increments from the gullets of the teeth up to the increment below the spine every two inches down the length of the plate. I color coded the results, each adjacent band is different by 0.001". I deleted the numbers for clarity.

Disston saw plate thickness profiles 011715a_Page_1.jpg

I found the results surprising as it appears that Disston may have tapered the area under the handles too.

Here's the profile for the plate I'm working on in this thread. I didn't grind in the handle area.

RS saw plate thickness analysis 011715a_Page_1.jpg

I ground this profile based on the information on the Internet concerning the taper grinding profiles created by Disston. Those sources show that the grinding was conducted along the spine of the blade from the toe back to the front edge of the handle. The true profile of my three Disston saws is interesting in that it shows they were ground at the heel of the plate under and around the handle area as well.

What period are the Disstons from? Photos of them might be handy.

also, if the thickness isn't constant along the toothline, then presumably not all of the original plate remains.

Lastly, I don't know your legend for colour vs thickness.

Cheers,
Paul

Originally Posted by pmcgee

What period are the Disstons from? Photos of them might be handy.

Here they are.

D8 crosscut.jpg


D8 rip.jpg


D7.jpg


[/QUOTE]also, if the thickness isn't constant along the toothline, then presumably not all of the original plate remains.[/QUOTE]

I know, I started measuring at ~1/2" above the gullets. The D-8 rip saw has the tallest plate and has a '66' stamp under the handle and the steel there shines like it is chromed.

[/QUOTE]Lastly, I don't know your legend for colour vs thickness.[/QUOTE]

Dark brown is the thickest, light brown is 0.001" thinner and so on. The maximum amount of taper was no more than about 0.005" to 0.007" on these saws from thickest to thinnest.

They were not hollow ground. If anything they are a little convex in profile.


Cheers,
Rob

Thanks. Technically the thumbhole is a "D8" and the others are as you said D-8 and D-7.

The others are maybe from the 40s/50s? are they aluminium medallions? The blocky handles indicate a modernish date.

I can't see the medallion of the thumbhole ... maybe it's 1928-40 date?

x Sorry. Checked my info ... hyphens after 1928 ... and the D8 etch puts it in 1910-28. The medallion would narrow that down to either pre or post 1918.

Are all the toothlines straight? sometimes they will be breasted a little.

Cheers,
Paul

My apologies. I obviously just invented that distinction for myself, or read it somewhere and adopted it.

They are all officially "D-x"

So there's the thumbhole pre 1928, the other D-8 (brass medallion) 1928-40, and the aluminium one is 1940s.

Move along, nothing to see here.

Paul

Originally Posted by pmcgee

My apologies. I obviously just invented that distinction for myself, or read it somewhere and adopted it.

They are all officially "D-x"

So there's the thumbhole pre 1928, the other D-8 (brass medallion) 1928-40, and the aluminium one is 1940s.

Move along, nothing to see here.

Paul

The D-7 screws and medallions are plated brass. Not sure what they're plated with as it doesn't look like chrome. Maybe transplants from another saw?

Originally Posted by rob streeper

The D-7 screws and medallions are plated brass. Not sure what they're plated with as it doesn't look like chrome. Maybe transplants from another saw?

Nickel.

Paul,

On the Disstonian page for D-7's some of the reproduced catalog listings refer to the saws as having 'striped back'. Do you know what is meant by that?

The medallion on the D-7 is a USA type suggesting post war manufacture. However the Disstonian site says

"Saws from the late 1940's and early 1950's had this medallion with sloppy execution. Its perimeter is wide. D-8's and D-12's were nickel-plated; D-7's were the same style, but not plated."

So maybe somebody changed them.

It could be similar to the Atkins "ribbon back" ... a polished strip along the back ... bit of a sales gimmick basically I think.

Originally Posted by pmcgee

It could be similar to the Atkins "ribbon back" ... a polished strip along the back ... bit of a sales gimmick basically I think.

Given my hardness measurements on these saws considered in light of the hammering experiment I just did I wonder if they refer to 'stripes' of hammer hardening down the length of the blade. It would make perfect sense.