Tuesday, 17 May 2011

Beutiful Disston No7

As well as the new saws that I'm making, I also have a collection of old saws. I tend to go for the larger rip and cross cut saws, leaning towards 19th C British saws, but I have a few American saws that have made it over the pond.

My better half often comments that the number of saws keeps on  increasing, and I suppose at some point I'll have to let some move on and find other homes. This will of course then free up some space for more saws.

Most of my old timers are in usable condition, some need straightening and sharpening, and I plan to try and get to these over the next few months.

I'll post these rejuvenated saws on here as they come back to life.

Here is a nice example of a lovely Disston saw. It's a No7 28" rip with 3 1/2 ppi, in very good condition and showing a nice breast to the saw line. Easy to date to 1896-1917 by the medallion.

This saw still has the remains of the paper sticker around the medallion, which originally would have read:

"Years Of Competition Against All Kinds Of Prejudice Has Proved--THIS SAW--To be Superior To Any Other Manufacture. Thousands Testify To This Fact."

Henry Disston was not one for modesty.

If you have a Disston, and want information about it, it's hard to beat the "disstonian Institute" website.


The breasted tooth line provides an advantage when cutting green wood. The breast reduces the number of teeth in  contact with the cut, this increases the pressure on the teeth in contact and also allows better removal of the damp sticky green saw dust.

Tuesday, 10 May 2011

Medallions design and fittings.

Making the medallion and brass fittings.

The medallions on my workshop saws are made from silver, this makes a nice contrast with the black American walnut. Brass was used traditionally, and I use brass on my site saws in combination with English beech, as they don't mind being treated a bit rougher.

My wife is a trained silversmith, which means that I have all the specialist tools to hand.

Having pierced the silver sheet to the required pattern, it is then soldered onto a second sheet of silver. This is then cut to the correct diameter, before polishing and fixing to the brass threaded bar.

The design on the medallions is based on the geometry of the daisy wheel. The daisy wheel is a geometrical symbol used by medieval builders to set out buildings and carpentry. It can be used to create angles and transfer complicated proportions, without the need for plans with dimensions, to craftsmen who were often highly skilled but illiterate.

The medallion and brass studs are polished and finished. The brass studs are made from 5/8th brass stock and threaded bar. The traditional split brass nuts are also made from the same 5/8th stock.

Saturday, 7 May 2011

Making the Handle.

As equally important as the steel quality is the handle. If the saw isn’t comfortable in your hand you won’t enjoy using it. The old British saws tended to have 1” thick handles while the American saws seemed to lean towards 7/8th, this doesn’t sound like a lot, but for me it makes all the difference.  I have an old Drabble and Sanderson saw from about 1835, this has a perfect handle for my hand size and grip. I’ve chosen 1” black American walnut for the handle, it’s not a traditional wood, but it will come up really rich and dark, and make a nice contrast to the metalwork.

I cut the handle blank out with a combination of band saw and a coping saw.

The handle is shaped with rasps then files to get the required shape. I kept the  original saw close by for reference while shaping.

Once the handle is fully shaped, I cut the slot for the saw blade. It’s impotent that you find a saw with a similar kerf to the blade thickness. I pack the saw up to the correct height for cutting the slot.

The handle still requires a final sand and polish.

Tuesday, 3 May 2011

Making the saw blade for a new rip saw.

I’ve always had and used old hand saws. There is nothing wrong with a modern, plastic handled saw, with its induction hardened universal teeth. In fact for cutting plywood, with its multi directional grain, they’re great, but they’re always short, and the teeth are too small for large green wood, and I’m not that keen on disposable stuff.

I’ve stopped and picked up countless old rusty saws in antique shops, checked the teeth and looked down the line to see how straight they were. Invariably they are past trying to bring back to life as a worker, but I have some excellent saws, some good saws, and some I was being too optimistic about.

A good old saw will outperform any modern handsaw, even when you allow for sharpening time, I’ve tested rip saws against new modern saws, and the cutting time is less than half that of the modern saw.

Sometimes things come together unexpectedly and take you off in a new direction. I found a saw doctor’s book on ebay that looked interesting, I hoped it might have some new (1920s) saw sharpening techniques for hand saws, it didn’t! But it did have a small section on the advantages of using a fly-press for cutting saw teeth in bandsaw blades. Around this time I came across a fly-press with tooling from a saw doctors, set up for re-toothing handsaws. Needless to say it joined my collection of tools in my workshop.

Originally I was going to re-cut some of my old saws. I could re-cut a new saw, but that wouldn’t be as much fun as trying to make a new saw from scratch, and I’d get a saw that would be customised to what I wanted.

Vintage saw design had a lot of facets, hand saws changed over time, with their pinnacle of development at the tail end of the 19th C. Tooth pattern, taper grinding, skew backed, handle position and steel quality all being changed and improved. I have a Disston No7 from this period, and decided to use that as a starting point for my new saw.

After a lot of research on the internet, and asking questions of those in the know I eventually found the steel type and grade required for my handsaw. Spring steel CS95, hardened and tempered to 530-570 VPN, this has a carbon content of around 0.95%. The quality of the steel is vital, it needs to be hard enough to hold its edge, and soft enough so you can file it and the teeth don’t snap off when setting.

So here is how I made the blade.

The new steel plate (750 x 225 x 1mm).

The saw is marked up ready for cutting. The new saw will be longer and deeper the the Disston by about an inch both ways. The saw length is dependent on the stroke length of your arm.

A guide was clamped to the steel plate ready for cutting with a 1mm cutting disk.   The cutting was carried out very slowly with multiple cuts, to prevent excessive heat from either buckling or losing the temper of the steel.

When all the cuts are complete the saw is held in a saw vice to have any sharp edges removed.
The back of the handsaw is marked up for taper grinding.

All 19th C hand saws were taper ground; this made the saw thinner along its back edge. This had three benefits.

It made the saw lighter and moved the weight to the tooth line, which improved control of the saw when cutting.

It made the saw less likely to jam in the saw cut.

It reduced the amount of set required,
smaller set = thinner cut = less effort.

Just as in cutting the plate, it is important that as little heat as possible enters the blade; I repeatedly cooled the blade every time it reached touch hot. (Somewhere after warm but still comfortably holdable in your fingers)

I added a nib to the back of the blade. This is completely decorative and not required, but it’s a nice touch that gives a nod to the old sawmakers.

The saw will have a graduated tooth line from 5ppi at the toe, to 3.5 ppi at the heel. (points per inch)
I punched the teeth with a fly-presswith guides to control the tooth size, angle and spacing. The previous tooth stops on the guide to set the spacing for the next cut. The saw is emerging from the blade. You can see the changes is tooth size as I move along the blade.
Each tooth takes about 5- 10 second to line up hold and punch. Cutting the teeth this way ensures no heat enters the steel at the tooth line.

The saw now has a slight curve in the blade from the stamping process, but this is removed later.

The saw blade is now completely shaped. It still needs a final polish, the handle fitted,sharpening and setting.

Another weekends work.

New rip handsaw

Just thought I'd kick the blog off with a taste of my new rip saw.

This is my first saw, I'll create some posts on makeing it, as time goes on and I'll also post images of my old and new saws that I work on.