Stelite Wide band sharpening?

[Satamax]

Hi everybody. 

Well, i should start investigating about the sharpening of my band blades.  There are approx 4" 1/2. Stelite tipped. And have some tension into these. 

I mean these have a slight curve from tips to the back. 

I wonder if the stelite ones are sharpenable with that tension, or if i need to remove it before sharpening. I know it is absolutely necessary for swagged teeth. 

[Bradm]

 Any pictures?  I've never worked with stellite, but my understanding is that the stellite is welded on to the tooth and then top and side ground to shape rather than swaging.

As for tensioning, a proper gauge, hammer, anvil and a lot of time to figure out how to properly flatten and tension.

[customsawyer]

I've only ever used one stelite blade that I got as a trial from WM. If memory serves it was 1.5x.055. I just sharpened it on my CBN grinder and it did fine. I doubt if it was big enough to have any tension in it so I can't really help you any.

[Satamax]

Any pictures?  I've never worked with stellite, but my understanding is that the stellite is welded on to the tooth and then top and side ground to shape rather than swaging.

As for tensioning, a proper gauge, hammer, anvil and a lot of time to figure out how to properly flatten and tension.

Here you go.


 
A blade with my hand for scale.  With a straightedge, i can tell that they're slightly tensionned. Between 1/32th and 3/64th.

[Iwawoodwork]

To me sounds like you are calling tension what I/we call set, The teeth are bent out from the main band left-right-straight and repeat on the smaller bands for most band mills.

[longtime lurker]

You need CBN wheels for stellite.

Mill I worked in that ran wide bands had an Armstrong grinder and that was all. We were under instruction not to run them too blunt so they didn't lose tension, they'd come off and be sharpened a couple times before being sent out to a sawdoctor who would sharpen them properly and tension them.

Hammering saws isn't some secret voodoo lost art. But it is a skill and requires training and practice,and the hardest part is finding someone whos prepared to teach you.

Lot of modern shops I believe that it's all pretty much integrated and automatic, there is a stretcher roller in the grinder somehow. Never seen one in person like that though, but I think that's what my sawshop guy is installing 

[longtime lurker]

To me sounds like you are calling tension what I/we call set, The teeth are bent out from the main band left-right-straight and repeat on the smaller bands for most band mills.

Tension is tension and set is set. Big bands have a concave in the band body to compensate for centrifugal force when working, that's called tensioning or hammering of the saw.

[Satamax]

To me sounds like you are calling tension what I/we call set, The teeth are bent out from the main band left-right-straight and repeat on the smaller bands for most band mills.

Hi Iwawoodwork. I'm talking about tension, and not set. Big bands like mine run on crowned metallic wheels, and have the same profile in the band. I know what is set, and it is not set.

[Satamax]

You need CBN wheels for stellite.

Mill I worked in that ran wide bands had an Armstrong grinder and that was all. We were under instruction not to run them too blunt so they didn't lose tension, they'd come off and be sharpened a couple times before being sent out to a sawdoctor who would sharpen them properly and tension them.

Hammering saws isn't some secret voodoo lost art. But it is a skill and requires training and practice,and the hardest part is finding someone whos prepared to teach you.

Lot of modern shops I believe that it's all pretty much integrated and automatic, there is a stretcher roller in the grinder somehow. Never seen one in person like that though, but I think that's what my sawshop guy is installing

Thanks a lot Longtime lurker. Ok on the CNC grinder. With integrated flatener and tensionner.  I haven't that kind of dough! ;D



An old "Winter" automatic sharpener. These were also sold under the Volmer brand.
I'll have to read the manual one of those days. But nearing 50, my sight is getting worse. And reading tech stuff is doing my head in sometimes! ;D

[longtime lurker]

Yah that Winter looks the same as the Armstrong grinders that were common  back in the day here.

And there is nothing wrong with them. Automatic grinder, automatic setter, and  manual tensioning was how it was done in every mill running bands and sawshop once. The new technology is no doubt better, and cheaper in the long term because it doesn't need the highly skilled labour to operate but it is expensive and takes a lot of volume to justify.

My plan when the resaw gets installed is to run mostly on 75 mm bands that I can sharpen and set in house and don't need to tension, and save the 150mm bands for special jobs and send them out for the sawshop to deal with. The issue isn't the cost of saw maintenance on the 150's it's the freight down and back, nearest shop that can deal with them properly is at the other end of the state 1000 km away. Although there's another plan says install the filing room and fly the sawdoctor up as required, but unless the right equipment shows up at the right price that is a longer term project.

At 50 I just about need glasses to find my glasses. Youth is surely wasted on the young!

[Bradm]

Hammering saws isn't some secret voodoo lost art. But it is a skill and requires training and practice,and the hardest part is finding someone whos prepared to teach you.

Lot of modern shops I believe that it's all pretty much integrated and automatic, there is a stretcher roller in the grinder somehow. Never seen one in person like that though, but I think that's what my sawshop guy is installing

I sold my bandsaw bench (36"L x 6"W x 4"T anvil, gauges, tension roller) and grinder about 5 years ago.  Modern equipment can flatten and tension in one setup fairly quickly and the top of the line grinders are CNC drag grinders that allow for free programming of the profile.
Hammering can be seen by some as a secret voodoo lost art, but that's due to very few people who know what to do.  You hit the nail on the head about the practice and training, but I'll go a step further and add that it takes a willing customer/mill that is going to allow someone to learn on their bands.
@Satamax,
If you have a wide band dealer or sawmill manufacturer that you can call, find out what radius you need your tension gauge ground to and then try to find someone to make it.  For myself, the hardest part was learning how to hold the band while reading the gauge (didn't do enough to get very good at it), how much pressure to use on the roller and how much force with the hammer.  You should be able to grind the bands with that grinder, just make sure you have a master template of your band profile and use it as a guide when shaping your wheel (use a desmond type dresser for cleaning the wheel between passes).

[Satamax]

Thanks a lot  Bradm. 

The Winter machine i have has the proper profile. An i rechecked the manual. They don't seem to talk about flattening prior to sharpen. 

Question to everyone. How do you check the wheel' crown? I know mine aren't centered crown. 

My take on it would be using a dial indicator and a perpendicular chariot to the wheel's face, which would have to be custom made, with dovetails etc. To plot the crown. 

But there should be an easier way. 

[fluidpowerpro]

I've never seen a crowned blade, but if it's what I'm imagining, maybe you could you make a gauge by casting one out of aluminum? You could push a blade into some casting sand to get a copy of the crown, and then pour it full of molten aluminum. Then the resultant casting could be set onto a blade to compare. Again, never seen a crowned blade so maybe Im way off base.....