Old Tyzack backsaw.

[planemaker]

I have an early Tyzack backsaw that the original handle was beyond repair and needed a new replacement. The saw plate dimensions (without spine) is 12" x 3 1/2" (0.028 gauge). and fitted with early split nuts.

The spit nut dia's were an odd size to try and neatly rebore seats for them on a new handle, so I will go ahead and use the modern versions sold by tfww.

As such I didn't want to use the pre existing holes in the saw plate, so I went ahead and removed just under 1 3/4" of plate to remove them. The remaining saw plate length is now at 10 1/4"

If you look at the following photo to my eyes the saw plate now looks too deep in comparison to its shorter length.



Using the dimensional table I worked put on a previous post, I resized the saw plate to a depth of 2/12". This gives me a usable depth below the spine of 2" .

IMO the comparative dimensions of the saw plate now with the spine fitted is much more visually balanced. Much more sleeker looking too.



On the previous backsaw I built I was using 0.020 saw plate and sharpened it at 14 tpi/ 10 * rake angle/ rip tooth. As this other saw plate is a of thicker gauge, a lesser tpi count will be required. 12 tpi should be about right, and I will stay with the 10 * rake angle. Later on near the rebuilds completion, if I find the smoothness of the sawn kerf is not to my liking, I will consider the option of applying fleam to the saw teeth.

Stewie;

[planemaker]

Before moving on to filing new teeth on the saw plate I lightly sanded the saw plate & folded back to remove any fine scratches.



Gunsmith Cold Metal Blue was then applied to restore some of the aged metal patina lost during sanding. As the metal surface reacts to the blueing agent its colour turns to near black appearance. After a couple of minutes the saw parts were then washed in soapy warm water to help slow down and stop the ongoing chemical reaction. After hand drying. I then used a nylon abrasive pad to lighten the dark blue appearance and bring it back to a softer patina. As you will see in the photo, the hardback looks to have a a very light indentation on the show side. Its only a surface defect, as the saw plate itself is perfectly straight when installed.

WD-40 was then sprayed over the metal parts, including the inside cavity of the folded back.




After refitting the folded back to the saw plate, a coat of soft wax was then applied to stop the chemical change completely. After 10 min. This was then buffed back to a shine. The final presentation of the saw plate assembly after blueing may not look as though I gained that much from its use. But you also need to take into account that all the freshly cut edges of the assembly are now the same patina as the rest of the metal surfaces.




Next job to do is file the teeth.

Stewie;

[planemaker]

I decided to leave the light indentation on the hardback the way it is. As it will naturally tarnish further with time, it will become less obvious to the eye.

On to filing the teeth. 12 tpi; 10* rake angle, rip tooth. I wont know if the teeth will need fleaming until after the handle is made up and fitted.

For those who may be interested I will quickly mention some of the strategies I use when filing the teeth. Keep in mind that I file all the teeth from the same side. If you do it differently ignore my comments, and continue the way you prefer to do it.

After notching the tpi along the tooth line. I then apply dykem. I then complete a full stroke of the file to each tooth spacing making sure I maintain the same rake entry angle. Apply dykem again, and repeat the same step.

Continue repeating the full stroke to every tooth, keeping an eye on the amount of flat remaining at the top of each tooth. The target is to end up with just the slightest hint of flat spot on each tooth.

If by chance you end up with the odd tooth that is on the verge of loosing the remaining flat spot if you include it in the full run of tooth filing, skip it, until the rest of the teeth can catch up.

Near the end of the shaping stage, If you find the odd tooth that has too much flat compared to the rest of the teeth, do not file it in a manner that would deepen its gullet more than the rest of the teeth. Instead, rotate the file slightly further forward and only apply the stroke of the file across the back edge of the tooth. That way you will not effect the primary rake angle (front of the tooth), and the tooth spacing will also remain consistent.

After all the teeth have just a very slight flat spot to them, you have completed the shaping stage of filing.

Now the big question. Do you sharpen the teeth before or after apply the set. I will answer the question this way. If each tooth does not receive the same amount of set to each point of the tooth, you are likely to see a slight difference of heights along the full length of the tooth line. Not what your after. Logic tells me that's its better to apply the set 1st. Then lightly joint the teeth to insure the top of each tooth are of the same height. Now your ready to sharpen each tooth to a point. Apply the dykem again. But this time only apply a lighter stroke to every tooth. Deal with any odd tooth flat using the same logic followed during the shaping stage.

When every tooth no longer has any remaining flat to the top of each tooth, you have completed the end of the sharpening stage, and the saw is now ready to do a test cut.

The following photo's show the saw plate after I have shaped, set, and sharpened the tooth line.





Next job is to make the handle.

Stewie.

[IanW]

......Now the big question. Do you sharpen the teeth before or after apply the set. I will answer the question this way. If each tooth does not receive the same amount of set to each point of the tooth, you are likely to see a slight difference of heights along the full length of the tooth line. Not what your after. Logic tells me that's its better to apply the set 1st. Then lightly joint the teeth to insure the top of each tooth are of the same height......

Stewie, I do it in the same order. i.e., form teeth, set, then sharpen. I don't seem to get any serious variation in height from the setting, it's more that I get some distortion of some teeth caused by the set, even though I try to position it very carefully so that the plunger meets the tooth squarely and does not hang over an edge. Fortunately, these small distortions clean up with a light stroke or two of the file. A light 'sharpening' stroke also leaves a better surface than the heavier stroke one tends to use when forming the teeth.

Nice job on your new old saw, and good write-up.
Cheers,

[planemaker]

Stewie, I do it in the same order. i.e., form teeth, set, then sharpen. I don't seem to get any serious variation in height from the setting, it's more that I get some distortion of some teeth caused by the set, even though I try to position it very carefully so that the plunger meets the tooth squarely and does not hang over an edge. Fortunately, these small distortions clean up with a light stroke or two of the file. A light 'sharpening' stroke also leaves a better surface than the heavier stroke one tends to use when forming the teeth.

Nice job on your new old saw, and good write-up.
Cheers,

Thanks Ian.

[planemaker]

The handle shape was cut out with a scroll saw and the edges were then rasped to 90* to the flat faces. The saw bolts holes have also been drilled out and saw bolts seated correctly.

The handle wood I am using is Tas. Myrtle. I am not overly concerned with the plain appearance of this wood at the moment. Van Dyke Crystals and shellac over the top will change its appearance to something more inline with the early dating of the Tyzack saw blade assembly.



Next job is to cut the blade slot and then do the mortise fit for the spine.

Stewie;

[planemaker]

The saw handle slot as well as the spine mortise are done. I must admit fitting this folded back was a lot more difficult than I am used to dealing with the slotted backs I normally work with. I did eventually achieve my objective of getting a nice close fit right around the mortise. Not a job for the faint hearted.

As you will see from the following photo's I have also started the work of rasping the profiled edges around the handle.

Stewie;

[IanW]

Lookin' good, Stewie. I'm interested to see how the transition from grip to cheeks works out when shaped. I particularly like the little flourish at the back of the chamfer on the cheeks - must 'borrow' that one!

Cheers,

[planemaker]

Lookin' good, Stewie. I'm interested to see how the transition from grip to cheeks works out when shaped. I particularly like the little flourish at the back of the chamfer on the cheeks - must 'borrow' that one!

Cheers,

Thanks Ian. Its all good fun.

Stewie;

[planemaker]

Here's something that might interest you.

If you look at the previous backsaw handle. I have re-used the same template design on this Tysack handle. Notice how I referenced the contour of the rounded profile edge using the outside shape of the grip.



Now look at the Tyzack handle again. Tell me what I did differently.!!




Stewie;

[IanW]

...Tell me what I did differently.!! .......

At a quick glance, the only major difference I can spot is that you've moved the bolt positions? The rear bolt is higher & closer to the front. Perhaps you did that partly to get it further away from the edge of the saw plate? In any case, the bolts look better positioned with respect to the cheeks, to my eyes.

I find it often requires a bit of juggling, when making handles for small saws. I like to keep the bolt holes a respectable distance from the edges to avoid any danger of splitting the plate (have seen a few old saws that have splits between the bolt holes & the edges). The bolts also need to be far enough apart that you don't have a too-flimsy bit of wood separating the two countersink holes. With small cheeks that can be difficult, but it helps that I can make my own smaller-sized bolts...

Cheers,

[planemaker]

At a quick glance, the only major difference I can spot is that you've moved the bolt positions? The rear bolt is higher & closer to the front. Perhaps you did that partly to get it further away from the edge of the saw plate? In any case, the bolts look better positioned with respect to the cheeks, to my eyes.

I find it often requires a bit of juggling, when making handles for small saws. I like to keep the bolt holes a respectable distance from the edges to avoid any danger of splitting the plate (have seen a few old saws that have splits between the bolt holes & the edges). The bolts also need to be far enough apart that you don't have a too-flimsy bit of wood separating the two countersink holes. With small cheeks that can be difficult, but it helps that I can make my own smaller-sized bolts...

Cheers,

Hi Ian. I was referring to which side of the grip I used to scribe the rounded profile line. On the previous handle I referenced this off the outside shape. On this handle I reversed that practice and used the shaping of the inside grip to scribe the outside grip profile.

Stewie;

[burraboy]

May I ask what type of drill you used to put the holes in the blade?

[planemaker]

Hi burraboy. I use this type of drill bit. http://blackburntools.com/new-tools/...ill/index.html

Its the smaller size bit that's shown in the middle of this photo;

Installed in a pedestal drill.



Stewie;

[IanW]

May I ask what type of drill you used to put the holes in the blade?

BB - I noticed you asked this question in another thread, & got a different answer.

The solid carbide bits Stewie pointed to would be the bees' knees if you are regularly drilling spring steel (keep meaning to get a couple for myself!), however, if you are in a hurry, & only plan to drill a few holes, a regular twist drill bit, plus plenty of lubricant will do it. You will have to re-sharpen the bit after just about every hole, however. A better option is to use one of the 'builders' drills' available in any of the hardware stores (can't remember what brand, but they have pictures on the packet of the drill sailing through wood, steel, & brick). They are carbide-tipped, & look like an under-fed masonary drill, but they will drill through spring steel easily. Their main drawback is that they are not very 'pointy', so you need to punch a decent indentation to stop wandering as you start them. Use a slow sped and don't use any cutting fluid - it wrecks them almost instantly!

Cheers,