Group Purchase - Brass back stock for sawmakers

**RayG** · 7th August 2009, 12:27 PM

Originally Posted by IanW

Ray - I meant to stick my nose in before, but have had a bit much going on...

As I've said before, I thought you were asking for trouble trying to slit such long lengths. While it is fine in theory to keep the stock as long as you can & only cut off what you need, it seems to me the small amounts you'll end up saving are going to cost you far more than it's worth. The brass is the most inexpensive part of the whole operation, after all. Even buying short lengths at retail prices as I've been foolishly doing, amounts to less than $5 for a 300mm saw back.

The most common sizes for small saws are 8, 10 & 12 inches, in old money, so if you went with 550mm lengths, you can easily get combinations of any of those saw sizes from that length (backs are slightly shorter than the blade by a variable amount, depending on the handle fitting). I suggest it will be unlikely that you will make successful saws much more than 350mm long from 20 thou (.5mm) stock unless you use very stiff backs & narrow blades. I made a rip saw with a blade 300 by 95 from 20 thou stock & found it a bit thin & flexible in use. It was just a test to see how a very thin blade compared with one slightly thicker, in this case, the thinner of the scraper blade thicknesses (~.6mm) Bunnies sell (or did sell, I bought the very last one a few weeks ago, & they don't seem to be getting any more of those in). There was a big difference in the feel of the two blades, with the slightly thicker one cutting just as fast, but easier to control. So my very limited experience suggests about 65-70mm of exposed blade seems ok for 20 thou blades, but after that they get a bit whippy. Maybe other sawmakers can comment on that?

The other alternative is to get yourselves a slitting blade & arbor (total cost about $30 with postage from McJing's). With a very simple jig & a bit of care in setting up you can do a very clean & accurate job. The trick seems to be many shallow passes - don't try to hog out too much in one pass.

I must admit, I hesitated to buy a slitting saw myself, as I fullly intended making 3 or 4 saws at the absolute max. I'm just finishing saw # 16

. I have a couple more planned (though not until I complete some more "important" jobs, or I will have to find an alternative place to eat & sleep!

) So my arbor & two blades has added about $3.50 to the cost of each saw, so far, making a grand total for materials of less than $25 per saw. They may not be quite Wenzloffs yet, but compared with the crude things they are selling for 3 times that price in the stores, they look a bit better & perform a lot better, so I'm happy......
Cheers,

Hi Ian,

The jig I am building is pretty simple, ball bearing rollers as guides, screwed down hard on the brass strip so there's no play either sideways or up and down, the slitting saw mounted on a fairly heavy bearings and made so that it can be adjusted up and down with a screw set up. Then feed the stock through with multiple shallow passes.

The advantage of longer lengths the ability to defer the decision as to how long a saw is going to be, You are correct, I don't expect anyone would be making saws longer than 14" (~350)

Regards
Ray

**IanW** · 7th August 2009, 01:14 PM

Originally Posted by RayG

The advantage of longer lengths the ability to defer the decision as to how long a saw is going to be, You are correct, I don't expect anyone would be making saws longer than 14" (~350)

Ray - yes, I thought that was the agenda, which is why I was pointing out there are only a few typical lengths most people will ever want. The price you indicated earlier on is pretty good, & the backs are going to be a relatively minor element of the whole cost equation. So what I was trying to say is that if they all decided what they were most likely to make, they could come up with a short length, which was a multiple of the long lengths & maybe save you a heap of bother. However, it seems you have the situation in hand, & will keep the crowd happy by not forcing any premature commitment.

Since you are doing this in a big shop with all the right gear, I assume you will have good technical advice, & the capacity to run adequate coolant whilst cutting? I only say that because (& I mentioned this once before) the first time I tried slitting, a friend 'helped' me (meaning he did all the machinery driving), after I made up the jig to hold the brass bar. We cut the slot in a single pass - the longest was 300mm. My friend reckoned we didn't need coolant for that cut in brass, so we didn't use any. Both of the slots we cut started out fine, but gradually curved to one side as the cut progressed - I didn't notice this until I got them home. Since we were using a thumping great 5 ton mill with a CNC table that would have carried a small locomotive, and the bar was well & truly restrained, and he took a deal of trouble setting it up straight & true, I can only think the saw blade got hot & warped during the cut, throwing the slot off. That hypothesis was borne out to some extent when I tried slitting with my own setup at home . If I took too deep a pass, the cut would start to curve up on the last 3rd or so. Cutting it in increments of about 2 mm at a time seems to result in a nice, clean & straight cut every time. BobL suggested I try using metho or something similar as a coolant, but I have no easy way to do that, and the slow & steady approach seems to work ok (& is a lot less messy!).

It may sounds like a lot of bother, but each pass can be made very quickly, so it only takes a few minutes to complete a slot. My diagnosis may be way off, & there may be an entirely different reason for our crooked cuts, but I'm sticking to the multiple shallow cut method for now - hate seeing 5 bucks worth of perfectly good brass bar made useless in 25 seconds or less!

Anyway, I hope we start seeing lots of pics of new saws from a happy band of sawmakers, soon....
Cheers,

**Heavansabove** · 7th August 2009, 10:33 PM

Ray, "A" sounds like a lot of work for you. I like the other posters are happy to take shorter lengths, especially if this can be done in the factory.

Cheers
Peter

**Harry R** · 8th August 2009, 07:33 PM

**thumbsucker** · 8th August 2009, 08:22 PM

I am down for four pieces at 900 mm.

I would be happy to have each of the 900 mm lengths cut into smaller pieces:

400 mm minus saw kerf suitable for No. 9 Back Saws, OR Large Tenon Saw
300 mm minus saw kerf suitable for Small Tenon Saws, OR Carcass Saw
200 mm minus saw kerf suitable for Dovetail Saw

**RayG** · 18th August 2009, 09:37 PM

Hi All,

I will be picking up the slit brass tomorrow, and we can begin the process of distribution.

At this stage, I will have a number of 1.2 meter lengths of slit brass, and a number of shorter pieces. I expect to be short of the total number that have been requested, so I will be organizing a second batch (now we know how to slit it!

)

So as to be as fair as possible, I will be limiting the first round of deliveries to one length per person.

First cab off the rank will be those who have already registered interest, but, as I indicated, only one length per person. (until we get the second batch under way).

Each length of slit brass will be matched up with the same length of (3" wide) 0.020 1095 bright finished saw plate. (Generously supplied at a great price by Mike Wenzloff)..

Now, who wants to make some saws?

Regards
Ray

**thumbsucker** · 18th August 2009, 09:41 PM

Me Please.

Great Job Ray.

**jmk89** · 18th August 2009, 10:00 PM

me too, please

**Bitslong** · 18th August 2009, 10:38 PM

oh yeah! I would still like some.

**Heavansabove** · 18th August 2009, 10:43 PM

Ray, thanks for efforts, please include me on the list.

Peter Evans

**STAR** · 18th August 2009, 10:56 PM

Yes please.

Thanks for all your stamina, many would have folded. I hope I can repay your effort with some quality work from this end.

Thanks again

Peter

**Harry R** · 19th August 2009, 12:32 AM

RayG

realistically, I will not get around to making any saws for some time. So if you're running short, I'm happy to donate my pieces to a more deserving sawmaker and wait for the next group purchase.

**kevjed** · 19th August 2009, 12:52 AM

Thanks Ray,
I'm not sure you have given any details of what each of us owe you yet Ray.
Please advise of what i owe you and I'm happy to do the direct deposit thing.
No rush my end but I'd like to pay up front as you have carried the cost for us all so far.
Feel free to PM me details as needed.
All the best and thanks once again.
Kevin

**Ian Wells** · 19th August 2009, 01:01 AM

Ian

**aaa** · 19th August 2009, 01:16 AM

In!

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