Thread: Looking for input into ideas for a special set of rollers

How about making up new rollers for a sheet metal jenny?
http://www.ebay.com.au/itm/Sheet-Met...item5b12b3326c

Michael

Thanks Michael, that's the sort of idea I'm chasing.

I'd be worried that a sheet metal jenny might not have the grunt required.
The blades are very stiff and quite thick (0.050") so will almost certainly need to be held on both sides of the rollers.

Hi Bob,

I assume its not as easy as turning the blade inside out and running the saw backwards for "awhile"?(that might lead to blade breakage??)

I think you're talking about peening and I think you've got the blade in the rolls the wrong way up. i.e A and C look pretty much the same. (though I've been wrong before)

Stuart

I wonder if you could increase the set on the bandsaw or do a slightly biased set that offsets the tendency to dive in the cut?

Originally Posted by Stustoys

Hi Bob,
I assume its not as easy as turning the blade inside out and running the saw backwards for "awhile"?(that might lead to blade breakage??)

Well I might just try that but as you say . . . . . . .

I think you're talking about peening and I think you've got the blade in the rolls the wrong way up. i.e A and C look pretty much the same. (though I've been wrong before)
Stuart

You are right they do look the same although C has a backing roller but A doesn't.

I haven't seen an actual roller just a drawing of one. I'll need to see if I can find it again.
.
.
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OK found it and it's exactly as I drew it.

Originally Posted by Toymaker Len

I wonder if you could increase the set on the bandsaw or do a slightly biased set that offsets the tendency to dive in the cut?

I tried that and it sort of works but then the cut wanders up and down like a rogue shopping trolley depending on how hard you push. It's like the blade starts to dive so you hold back a bit and then it self corrects but goes too far and then self corrects the other way - the cut is pretty awful - I get a much better cut on my chainsaw mill .

I found a not very good photo of a commercial roller
Here you can see how HD the whole thing is.
The lower roller on this setup has a small raised section against which the back of the blade can track.

Google bead roller.......... pretty much the same as the jenny Michael suggested but might give you more ideas as it seems to bring back more welded from plate.
I don't think 0.050" is to thick for a bead roller, you don't have to do it in one pass after all.......... though it has been awhile since I used one. Surely there will be someone about some where that has one.

This is what I think is going on (though granted I'm extending hammer blows to a roller)

http://chestofbooks.com/home-improve...l#.VWXIIdKqpBd

Fig 254
http://chestofbooks.com/home-improve...l#.VWXIMNKqpBd


Either way, doesn't matter much, once you've got the machine turning the blade the other way up if needed wont be a big deal . I believe Ray wanted to learn how to hammer straight a saw blade, he even has the avil. Maybe you can talk him into it (ok granted he was talking about circular saw blades)

I'll be watching with interest.

Stuart

p.s.The quenching in mercury rings a bell.. I might have that book lol

Hi Bob,
the local sawmill where I used to live had a very young saw doctor that could planish round and band saws back to new.
Now even the sawmill has gone. This kid was outstanding at what he did (not that this helps). They had all the gear which may be at the local museum now and I will be going there shortly to get a couple of my things so I will ask.
The point is, maybe there is an old (or young) saw doctor out there that may help. With the timber industry the way it is, who knows.

Phil

BobL, look up English wheels as used by panel beaters, there may be some ideas there. Hafpos will have one or two on display if you are near one of their shops.

Originally Posted by bob ward

BobL, look up English wheels as used by panel beaters, there may be some ideas there. Hafpos will have one or two on display if you are near one of their shops.

Yep, exactly my thought - that roller is basically a one-dimensional/directional English wheel. It stretches the metal to change the curvature.

Problem is, there's a limited amount of times you can do this without work-hardening happening, at which time micro-cracks will propagate and result in blade failure. It's one of the reasons the Lucas type mills are - IMO - better for production of building size timber and bandsaws better for furniture grades where minimal loss in the kerf and slow speeds are more acceptable. I've given a lot of thought to building one or the other.

Hell of a lot less teeth to sharpen on a Lucas mill, too......

PDW

Thanks for the input guys. I'm going to H&F to pick up some stuff later today and will have a look around.

I still worry about whether a standard bead roller or english wheel would be able to apply the pressure require. It's not just the thickness but the hardness of the steel in the blade.

Problem is, there's a limited amount of times you can do this without work-hardening happening, at which time micro-cracks will propagate and result in blade failure.

Yep that's correct - long term experience by the pros suggests this can be done around 20 times without breaking blades.
This is about the same number of times blades can typically be sharpened anyway.

It's one of the reasons the Lucas type mills are - IMO - better for production of building size timber and bandsaws better for furniture grades where minimal loss in the kerf and slow speeds are more acceptable. I've given a lot of thought to building one or the other.
Hell of a lot less teeth to sharpen on a Lucas mill, too......

True, but the auto sharpener does a 5.3 m long blade in around 6 minutes. Setting takes around 3 minutes.

I have located a couple of sets of beaders at a high school 3.5 drive from Perth.
They are up fot "tender"
They look like they might be HD enough?

Hi Bob,

You may have a look around for a Swayne Robinson Metl-Former vise. I have a picture but for some reason am unable to upload it. They've been out of production for years but the design would likely do what you want to achieve. It's a vise with threaded recesses in the tops of the jaws allowing the fitting of a variety of metal forming implements, including rollers. If I get a chance I'll post pictures of mine.

Cheers,
Rob

Originally Posted by rob streeper

Hi Bob,

You may have a look around for a Swayne Robinson Metl-Former vise. I have a picture but for some reason am unable to upload it. They've been out of production for years but the design would likely do what you want to achieve. It's a vise with threaded recesses in the tops of the jaws allowing the fitting of a variety of metal forming implements, including rollers. If I get a chance I'll post pictures of mine.

Thanks Rob, I have seen these before and I see one on eBay but a bit expensive considering it has bo rollers.