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Thread: Is there a 'best' way?
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7th Nov 2019, 07:41 AM #1Philomath in training
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Is there a 'best' way?
Some of you will know that being the cheapskate I am, I weld up my own bandsaw blades with TIG. The resulting weld needs to be ground down to fit through the guides and I've been doing that with an angle grinder ever since I started doing this. The results are not always as good as I would like though - grind off teeth un-necessaily or grinding into the blade and thinning it.
I had a thought the other day that a jig using a small angle or bench grinder may be the way to go. However, I can't decide which is the best way to orient the wheel.
Grinder.jpg
Both of these options would do the job and I have a supply of small wheels that would be suitable.
The blade will be clamped to a table so really it is just a matter of skimming the surface with the wheel so that the 'excess' weld is removed (flip over and repeat...)
Can anyone think of a reason why one orientation may be better than the other?
Michael
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7th Nov 2019, 07:54 AM #2Senior Member
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Option 1
- Because the grinding wheel surface speed is constant across the contact area on the blade making for a more even grind
- Because it makes it more likely that only one point on the wheel contacts the blade, if there is any bending
- Because we are taught that you should only grind on the periphery of the wheel
- Because the only commercial blade grinders I've seen do it that way
Regards,
Andrew
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7th Nov 2019, 08:28 AM #3Most Valued Member
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Hi Michael,
given that you have been joining your blades for some time and I have never done that before I'm assuming you have thought alot about different ideas. Not withstanding the this, have you tried setting up a jig on the surface grinder?
Obviously I have never tried it before but it seems like half the work in seeting up is already done. Just need to make two flat plates, each with a rebate and/or a clamp that can clamp on each side of the weld and the sit on the mag chuck. High enough so the mag chuck wont pull the unsupported part (with the weld) down and high enough so the weld can clear underneath.
Would that work?
SimonGirl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.
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7th Nov 2019, 09:03 AM #4Member: Blue and white apron brigade
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It's a long shot but option 2 is going to create more scratches that finish at the side of the band creating potential fracture starting points?
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7th Nov 2019, 09:15 AM #5
Back in the days when I taught at a high school, we used to buy the bandsaw blade in 100 ft rolls.
The blades,OK! they were woodworking blades ,were silver soldered.
To provide clearance for the guides,the soldered faces were dressed with a rotary stone on a die grinder.
I always used the periphery of the stone.
My opinion, is that the grind lines need to be across the weld line ,not parallell with it.
The blade is subjected to a lot of bending moments while being used, so stress lines however small could be a factor in blade breakage at the weld line.
Grahame
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7th Nov 2019, 10:09 AM #6Diamond Member
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Out of interest what wire are you using to TIG weld the blades with? Are the coils of blades easy to get hold of?
Thanks
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7th Nov 2019, 11:39 AM #7China
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All the band welders and grinders I have used, use the rim to grind and, and have a rotating guard so you can grind the join top and then underneath, without having it manipulate the band
Otherwise you need to turn the entire band inside out to grind the opposite join, this also leaves the resulting scratches in line with the blade, some say this less likely to create a stress fracture
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7th Nov 2019, 11:43 AM #8
Com_VC
I would try one of the bandsaw blade manufacturers .These are the people who will make your bandsaw to size.
The will be buying stock bandsaw blade by the roll.
Every major city will have one.
To get a basic idea here are American prices.
https://www.mscdirect.com/browse/tn/...219&mc=0821660
Of course I am not suggesting that, the freight is over the top.But it will give you an idea on what you might expect to pay for a whole roll.
Grahame
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7th Nov 2019, 02:04 PM #9China
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This illustrates what I am saying https://www.youtube.com/watch?v=TxQxQo7ExGE
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7th Nov 2019, 07:26 PM #10Philomath in training
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It probably would work but most of the work is in making the jig to hold the blade. Once that is done, the source of rotation for the wheel is relatively minor. The detracting thing about using the SG is that I would need to turn the blades inside out to grind both sides. With a (small) specialist jig, I can design it to avoid having to do that. I would also prefer not to have the blade come near the SG mag chuck on the off chance that I will then have a magnetic bandsaw blade...
I use normal steel filler wire. Industrial supply places stock rolls of blade or can get it in.
https://metalworkforums.com/f65/t143...bandsaw-blades
Michael
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7th Nov 2019, 08:05 PM #11Most Valued Member
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I MIG weld my blades, then clean them up with a used 60 grit flap disc over a timber former, a bit larger than the diameter of the wheels on a 6X4, have a couple of cutouts to allow for clamping.
If you get a chance have a look at a welder that is fitted to some of the larger Bandsaws.
From memory the stones are about chest height, I have a feeling that there are 2, as they can do both sides at once. Can't really remember how this was achieved though??
As you're looking at making something similar, you'd need to have the platten moveable to allow for weld material on both sides, if using one stone.
KrynTo grow old is mandatory, growing up is optional.
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7th Nov 2019, 08:12 PM #12
HI Guys,
A guy that I've been to, who makes blades and knives for all sorts of machines, has a device that you clamp the blade ends into and they are pressed together. They become molten on the ends for a second and weld together. He then anneals the joint, barely getting it red with a gas burner, before using a die grinder with a small stone to remove the flash on either side. He does turn the blade inside out when doing this. Also he holds it over a device a bit like a section of the edge of a wheel, that he holds the blade over while grinding. He has just made a Bi metal varitooth blade for me, it took him less than five minutes to do.Best Regards:
Baron J.
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7th Nov 2019, 10:58 PM #13China
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Then there is the other option that pattern makers used to use and that is to scarf the joint and silver solder it, if done correctly very little clean up is required
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8th Nov 2019, 07:40 AM #14Philomath in training
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I first got a saw doctor to make up some blades for me with this method. They screwed it up, which is why I've welded them myself ever since (they got the scarfing wrong, so the blades peeled apart very soon). Weding is more attractive too because my bandsaw does not have a tensioning device that can cope with extra blade length. With a welded butt joint is much easier to get a correct length blade.
Yes, we had one at the Uni and I was learning to use it before being tossed out. It was one wheel with a rotating guard. The issue with that was that it still required some technique to get the weld ground properly.
A resistance welder like that would be very nice, and some even allow annealling with the electric current but the price for buying one was around twice what I paid for the saw.
I'm still using an angle grinder at the moment with a flap wheel, but it does not give a consistant grind in my hands. This grinder will hopefully make it a bit easier to get a consistant blade. I know when I got the Darex I suddenly was more interested in sharpening drills when needed rather than putting it off. I hope with something like this it will cure a reluctance to put on new blades when I should, rather than for example running a fine tooth blade in thick material because that is all I have.
Michael
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8th Nov 2019, 11:54 AM #15China
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I always silver solder my blades I have never had a problem, I have only done this on woodworking machines, I have never broken a blade on the metal band saw.