Update on wire brushing



See the explination I posted to Ted.
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wrote:

See the explanation I wrote to Ted a bit further in the thread. I'll try to get a transcription of Weiler's application pages, they are superb.
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Tom Gardner wrote:

Ok you sell wire brushes, however I am sorry but I have to disagree with you on theis question of reversing rotation . you can all try this simple test at home. take you 2 to 6 month old tooth brush, take a pair of sharp kitchen cissors, trim 1/8in off the bristles wether there real or nylon. then use it. youll know the difference right away. Why? because you have restored the end of ythe bristle to its original sharp square end. its that sharp ness that does the work wether its a tooth brush or your rotary wire brush. Restore that sharp edge and you restoreits cutting ability. its like sharpening any cutting tool wether its a drill,lane iron , chisel orlathe tool. Come on!! you all know a blunt tool cuts less than a sharp one. By reversing you then use the other side of the wire thats not been blunted. All cutting tools get blunt with use ,so does a wire brush. And yes, its a good enough resason to buy a new one, if you dont know how to sharpen it.
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I don't have much access to markets that service end users so I don't have a vested interest in "selling brushes". I don't sell retail, my biggest markets are food service and industrial.
If you reverse the rotation before the wire starts to lay, that's OK. What usually happens is the operator starts pushing the work harder into the brush and starts a cascade failure. It's an unconscious act. Most people under-power, under-rev and push to hard, then reverse the brush. You're bang-on with the shape of the ends of the wires, it's the edges that do the work. A good oil tempered wire brush is self-sharpening to a good degree and the wire will microfracture exposing a fresh cutting edge do to highly localized heat cycles on a molecular level in the very tips of what is basically tool steel wire. If you reverse the rotation on an oil-tempered wire brush after it has started to lay, the wire will start to break at the hub due to hysteresis. An inexpensive hard-drawn wire brush will wear smooth ends on one side of the wire instead and is not as susceptible to the hysteresis that prematurely fractures the wire that is more the equivalent of hot-rolled steel, so reversing it won't do as much damage to the molecular structure of the wire. A brush can be sharpened using a stone.
You're toothbrush analogy is off base because as you shorten the trim of any brush, you change the stiffness in addition to squaring-up the ends. But, in a way you are right by reversing rotation if you only use hard-drawn wire. All imports are of this variety and they have good value for occasional or home-shop type use. If you have an oil-tempered domestic industrial type brush and the hp and speed, don't reverse it, you won't ever need to or want to. Any time you see a wire wheel that the wire is brass plated, it is made from rejected tire-cord wire. It's hard-drawn and not really brush quality, it's really, really cheap at 19 cents a pound. Good hard-drawn wire costs $1.75 a pound and good oil-tempered wire costs $3.50 a pound. Typically, a hard drawn 6" wheel sells for about $4.00 in a blister pack. An oil-tempered 6" sells for about $13.00 and a 6" knot-type for about $20. Finer wire costs more. Stainless, about double. I'd venture to guess that you use import hard-drawn wire wheels?
All this applies to crimped wire wheels, knot-type wheels are a different ball game. You'd better have the hp and speed or they won't work well at all. Too much speed and they don't work right, they burnish rather than cut. Imports are all hard-drawn wire and don't work well or last long. There's a plethora of knot-type cup brushes that are imports that are just dreadfully inadequate, but they sell like hot cakes!
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On Sun, 18 Nov 2007 19:45:07 GMT in rec.crafts.metalworking, "Tom

And also because it makes the wire bend backwards at the point it's already bent.
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...

McMaster is one of my favorite vendors. How are they as a customer?
The reason I ask, I know of at at least two examples where a good vendor is a terrible customer: 1. Walmart, 2. The Produce Distributor for my area
Karl
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Walmart is not a good vendor. Most of their things that I bought, lately, broke very soon under regular use.
i
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Tom, the brush is McMaster item 4840A48. I doubt that I have a 1 HP 3450 RPM motor, but these are not hard to come across, so I will keep looking. I currently use a 1/2 HP motor.
i
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On Sat, 17 Nov 2007 04:42:47 GMT, with neither quill nor qualm, "Tom

Can you say "porcupine"? I knew you could.

But your brushes can be mishandled like that and keep on ticking, right? No wonder you get the big bucks.
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From what I've seen in periodic browsings through the tool section in the Menards near me, they seem to sell just about the cheapest tools on the market and I try to limit my purchases there to stuff that isn't safety critical or needed for more than a use or two.
Mike
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I have finally come to the same conclusion. McMaster price is not much greater and the quality is much better.
i
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