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By xy mosian
#492864
pedder wrote:
Nike comes to my mind: Just do it.

Cheers
Pedder


Thanks Pedder Nike's advice, via your good self, should be my motto. I do tend to think things through for far too long. In fact a one time boss of mine accused me of "Making a career out of a project" on several occaisons. :oops:

xy
User avatar
By bugbear
#492865
xy mosian wrote:
Now I've done a bit of metal work, school stuff mostly, and I cannot think how this could be machined without some fairly complex machinery.


From an old post to OLDTOOLS:

paul womack wrote:

> So; has anyone out there tried non-uniform
> teeth in a saw?

Heh, heh. At the risk of replying to my own post,
I have (now).

Summary; it took a while to do, and the saw cuts well.

Longer version.
I spent 10 minutes filing off the old 14 TPI teeth,
and then filed a 1/8" camber onto the toothless edge.

Since this saw is to be used for tenons and dados,
I felt a "breasted" edge was desirable.

I then SiC'd and polished the blade - this is normally
difficult due to the teeth shredding up your
abrasive, so I made the most of my opportunity

The layout was done by using a computer to print
out the graduated teeth pattern on paper,
and simple gluing the paper on to the saw.

Initial filing is tricky - you need to make a "notch"
somewhere in the gullet of each tooth. Once you have
a prelimnary gullet, it's quite easy to guide the
triangular file left/right rather accurately
as you work downwards.

Once I'd more or less created the teeth, I removed the
paper, and did a final shaping and evening up pass.
All the work to this point was done from one side of the
saw. I find this *MUCH* easier, especially when filing BOTH
sides of a large tooth to get it's size and position correct.

I then applied moderate set with a modified Eclipse
#77 saw set.

SIDEBAR - the Eclipse #77 saw set
Eclipse #77 saw sets normally apply too much set -
the marked TPI settings around the anvil are WAY off.

Worse, you can't just use the setting for smaller teeth,
since the angle of the set is more or less constant (at around
20 degrees). If you use (e.g.) the 10 TPI setting on 6 TPI
teeth, you just bend the top part of the tooth, but still
at 20 degrees. This does give you less total set,
but in the wrong way.

I therefore removed and reground the anvil disc from
one of my #77's (I'm not a c*ll*t*r, no sir).

I ground a good amount of material from the thickness
of the disc (thus reducing the amount
of set) and then bolted the disc to the end
of a plywood scrap, and clamped the scrap in my
giant honing jig. I could then set the jig to my desired
angle (around 13 degrees) and carefully grind the disc.
Rotating the disc gradually on the bolt allowed me to make a
varying size, contsant angle bevel around the circumference of the disc.

Doing this the "quick" way by carefully eyeball the spiral
took very careful judgement and several passes.
It would probably have been quicker to measure/mark some depth stations,
grind these accurately and then interpolate.
END

(later I realised that that end of the plunger needed to be at the same angle as the face of the anvil, and ground the plunger's end face too)

BugBear
By xy mosian
#492916
Strange BB, I was reading that very post on 'Old Tools' earlier today, completely missed the sidebar about the '77. Was it more than just a gut feeling that led you to a setting angle of 13 degrees?
I had worked out the thinning of the anvil to reduce overall set, but I'd still like to know how such a thing could be machined. That of course is a different story.

xy
User avatar
By Pete Maddex
#492961
Hi,

I checked my 77 style saw sets
Image
L to R Eclipse77, Eclipse 77, Somax, Unbranded
None of them have big enough cheeks to drill and tap.

But it did show up a startling difference in the two Eclipse 77 the hammers are very different sizes 2.36mm and 1.51mm.
Image
Any one come across this before? They are both marked Eclipse 77 and Made in England but the fatter one looks older, its has more metal to it, the thinner one looks simplified and streamlined, like the accountants have got there hands on it.

Pete
By xy mosian
#493012
Pete, one of the things that makes my recent, 12 month old, '77 horrible, is the fit of the hammer in the 'sliding clamp?'. It is noticeably thinner than the same part in the thirty year old. The 'sliding clamp' in the older model is machined steel whereas in the newer it looks like a plastic casting (I kid you not!). The fit between the hammer and clamp? You could drive a bus through the gap as they used to say.

Another great shame because the design, to my mind, is well thought out. :cry:

xy
User avatar
By bugbear
#493089
xy mosian wrote:Strange BB, I was reading that very post on 'Old Tools' earlier today, completely missed the sidebar about the '77. Was it more than just a gut feeling that led you to a setting angle of 13 degrees?

It's just "less than 20"

I had worked out the thinning of the anvil to reduce overall set, but I'd still like to know how such a thing could be machined. That of course is a different story.
xy


OK. Since there seems to be some confusion, I'm made diagrams, which I hope will help.

Let's start with my claim that the plunger angle needs to match the anvil angle (which also implies that the anvil angle must be constant around it's circumference).

Image

If the plunger angle is too obtuse, the tooth can't be bent over as far as the anvil allows, so that's wrong (left hand side picture).

If the plunger angle is too acute, the teeth is subject to excess pressure (since the plunger effectively makes a point contact), so that's wrong too (right hand picture).

We're left with "they must match".

Moving on to "adjusting the set".

Image

In the left hand pictures (representing the #77 as supplied), the amount of set is adjusted by rotating the anvil. This has the effect of moving the "location of the bend" up or down, because of the spiral.

Since the anvil angle is constant, moving the bend point up reduces the set, moving it down increases it. This can be seen on the diagram.

However, if one wishes the bend to be at the mid point of the tooth's height, the amount of set is NOT adjustable - it is determined by the anvil angle.

Further, on a stock #77, the spiral bend point does not go all the way to the edge of the anvil disc, so there is a lower bound to the set.

For this reason, I reground an anvil (as described) so that the angle was lower, and so that the spiral went all the way to the edge. This is the case on the right hand pictures.

The lower angle means that you get less set for a given bend point (i.e. tooth size, if you're following the mid point recommendation).

So this modified #77, in toto, gives less set for a given tooth size (due to the lower angle), and will handle small teeth (due to the spiral going all the way to the edge, and the narrowed plunger).

While I'm on, I'll also point out that older #77's have narrower plungers.

BugBear (exhausted!)
Last edited by bugbear on 19 May 2010, 10:35, edited 1 time in total.
User avatar
By bugbear
#493091
Pete Maddex wrote:Hi,


But it did show up a startling difference in the two Eclipse 77 the hammers are very different sizes 2.36mm and 1.51mm.
Image
Any one come across this before? They are both marked Eclipse 77 and Made in England but the fatter one looks older, its has more metal to it, the thinner one looks simplified and streamlined, like the accountants have got there hands on it.

Pete


I bet the right hand one is older. Look at the much nicer and clearer number markings on the anvil. it also has the (desirable, IMHO) narrow plunger.

Any chance of pulling out the anvils (don't mix them up!) and photographing the spiral, and measuring the angle (see my post for what I mean by angle)?

BugBear
User avatar
By Pete Maddex
#493116
Hi,

My money would one on the left one being older, it’s more curvaceous than the one on the right.
I will pull then tonight.


Pete
By lurker
#493141
BB / Pete

Whichever of you is correct ( I'm with BB as it happens) this tool certainly changed over the years ( quality of casting, plunger width, fine/course adjustability)

Amongst those I have :roll: some are much better than others. If I had any sense I hoick quite a few in the bin as I'd never contempate using them

At some point Eclipse lost the plot, so we should not talk about "a 77" as if they were all the same quality
By xy mosian
#493180
bugbear, thanks for that explanation.

The anvil on my older '77 (30yrs) does not have a clearly defined corner where the spiralled chamfer meets the flat of the anvil face. Visually this looks rather like a blend radius. The 'striking' face of the hammer is very slightly curved, really very slightly. It certainly does not match the curve of the anvil. Hammer thickness is 2.4mm. However the edges of the'striking face' are chamfered reducing the width of the face to 1.9mm, as nearly as I can tell with a dial caliper.

On the newer '77 (2yrs) the same, chamfer/face, corner is definitely an angle. As for the hammer face, that can easily be seen to be curved even without the aid of a straight edge. Hammer thickness is 1.8mm.

I find it kind of interesting that the screw thread used to hold the anvil in place is the same on both models. 4.7mm diameter for the screw, now this could be 3/16", I wonder if they are using old tooling?

But, as lurker said, "At some point Eclipse lost the plot, so we should not talk about "a 77" as if they were all the same quality". Same as nearly all once great tools really.

xy
User avatar
By Pete Maddex
#493260
Hi, Chaps

Here they are...
Image

The anvils
Image

Measurements, maximum depth of spiral and width of spiral
Image

Angle
Image

The one on the right is what I think is the older one, but the anvil looks cheap and the bevel is rounded over, the left hand one is nice and crisp compared to it. But the casting is more ornate on the right hand one, the other seems like its been reduced of any unnecessary ornamentation.

Pete
By Corneel
#493266
This is a very interesting thread, so I thought after long time lurking, let's registrate.

Bugbear, your diagrams of the Eclipse 77 are very enlightning. Now I understand why they made the tpi gradiations on the anvil. So your tooth will be bend at the right height . A 6tpi tooth is a lot larger, so will need to be bend a lot lower then a 12tpi tooth.

The problem though is the rediculous amount of set you get at the 6tpi setting. My sawset would geive me something like 1mm on both sides! Even for a 6tpi saw in wet firwood, that is way too much. In fact the neccessary amount of set doesn't variate much between low or high tpi's.

So the perfect Eclipse 77 anvil would have one setting for set and the edge of the anvil would have gradiated angles. A 6tpi, being a much larger tooth, you would need a much lower angle then at 12tpi, to be able to bend the tooth at a lower point. Of course you would then need several anvils for differnent amounts of set.

But this being not a perfect world, I just use the Eclips77 mostly in the 12 tpi setting, even when I set a 6tp saw. And I have another one with a narrower hammer and even less set, because I grinded down the anvil, for when the time comes to sharpen my finest backsaws.
By xy mosian
#493299
Hi, Corneel welcome to the 'Mad house' :)

I was just beginning to think this thread must be getting a bit dry for onlookers and here you are. I agree about the calibration of the anvil on the '77, I just ignore it. However I do find the tool to be relatively easy to use and it does give repeatable results along the blade.
That's a nice approach to making a setting tool for finer toothed saws. One that has been mentioned here abouts. I must get around to grinding the thickness of my second anvil down. I think I'll have another look at bugbear's changes to the chamfer angle too.

Of course for finer teeth I'll need to add more magnification too :)

xy
By xy mosian
#493317
Pete, if it is of interest the '77 on the right of your picture looks just like the one I bought thirty years ago. The anvil looks the same too although I haven't done those measurements.

Just in case any want to see other types of saw setting plier:-

http://members.acmenet.net/~con12a/saw% ... rindex.htm

Shame there isn't more information really

Have fun

xy
By Corneel
#493389
Just been thinking it over a bit more.

Adjustable sawsets don't really work. You can't change the angle of the hammer, if you would use different angles for different tooth sizes. And when you use the same angle and same set, the bending point is probably too high on the coarse teeth and too low on the finer ones.

So in fact you need a seperately prepared sawset for every possible tooth.
That's probably a bit too much. But you could lump them into 3 or 4 groups and prepare a sawset for each group, and never change the setting of these anymore. So get out the sinus and tangus tables and start designing the perfect sawset geometry :lol: