17 inch contact wheel grinder

N

Natlek

Joined
Jun 9, 2015
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Ok , I finally find time to make tracking wheel/mechanism for my new grinder . Plan is this............I will use pulley system from motor ON contact wheel . Motor is 3 phase , 2hp and 1400 rpm and with 1:1 ratio pulley I will have about 32 m/s belt speed which is more then enough . For tension I will use gas spring because contact wheel is drive wheel in same time and I don t see advantage here of ratchet mechanism ?
It s time to send this wheel for polyurethane treatment so I have two question ............WHICH duro/shore ?? hardness I need to use and how thick layer of polyurethane ? I have no idea of wear rate and durability of polyurethane used for this kind of work ? All I know is that it is better then rubber ? Thanks for any help .

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I would go 70 Shore A for hardness. "Car tire" hardness.
 
90 durometer would be my choice for a fast and large wheel.

That looks like a motorcycle rim? You definitely need to have the rubber coater check the balance. At the speeds you are talking about things can come apart pretty easily - 32M/s is 71 MPH or 115 KPH. Normally, the mass of a lathe turned wheel and rubber tread is part of the setup that makes things run smooth. Not saying it won't work, but the weight distribution on that rim is not symmetrical. I would certainly be well away from it the first time I powered it up.
 
Thanks @Stacy E. Apelt . Yes , it is front rim / 16 inch / from motorcycle which can run over 200 km/h . I have all necessary equipment to balance wheel on bike and car , actually that is part of my daily job :) So balancing that wheel after coating with rubber is no problem at all .
How thick layer of polyurethane ? It is quite expensive ... Is it two centimeters enough ? I don t know wear rate of that thing so I ques in some time I will need to dress the rubber ?
 
I still have not started working on this project . Yesterday I ran into this video ...... he used a timing belt on contact wheel ? I make some measurement and I found that I have prefect belt /50mm width/ to use it on my 17 inch wheel ? It will fit perfectly on this wheel . What do you guys think about this ?
 
Funny you bring this up. I had considered a timing belt on a big wheel build. But being almost 23” in diamater made me rethink having one made. Waiting on an estimate right now on a 22.9” expanding wheel.

Let me know how well the timing belt works.
 
So you think this will work like serrated wheel ? If works will last forever. . .
Well , my wheel is 1280mm circle length .Belt is right 1280mm length in pitch which mean that I need to turn wheel little on lathe to get press fit ?
You can find right belt length for 23 inch wheel , I think ?
 
Definitely 70a duro. 55 is too soft for al but higher grits and 90 gives a lot of chatter 60-180 grit.

Bought all three from sunray when I first got started only kept the 70.

Cant wait to see you finish this Natlek, I've been toying with building a 20"
 
Natlek said:
So you think this will work like serrated wheel ? If works will last forever. . .
Well , my wheel is 1280mm circle length .Belt is right 1280mm length in pitch which mean that I need to turn wheel little on lathe to get press fit ?
You can find right belt length for 23 inch wheel , I think ?
Click to expand...

Yeah 2x72 belts fit. Salem and I are trying to build a mono wheel 2x72 grinder. It would just use one wheel and the belt would slip over it. When turned the wheel would expand and lock the belt into place.
 
JTknives said:
Yeah 2x72 belts fit. Salem and I are trying to build a mono wheel 2x72 grinder. It would just use one wheel and the belt would slip over it. When turned the wheel would expand and lock the belt into place.
Click to expand...

Could you explain the expanding wheel technology? Does it just have a lot of spokes with curved sections on the end that move radially in/out? Mainly, how is balanace going to be maintained?
 
Tin.Man said:
Cant wait to see you finish this Natlek, I've been toying with building a 20"
Click to expand...
There are only one place in Macedonia where I can send this wheel for rubber coat and they have no poly with right duro hardness ....They say that they will call me when they have that poly................I would have done this project long ago :mad:
Now I like this idea with timing belt....I m working on rotary platen too , now i'm thinking what if I use this kind of belt :)
 
JTknives said:
Yeah 2x72 belts fit. Salem and I are trying to build a mono wheel 2x72 grinder. It would just use one wheel and the belt would slip over it. When turned the wheel would expand and lock the belt into place.
Click to expand...
That s best solution if you succeed to make it
 
JTknives said:
Yeah 2x72 belts fit. Salem and I are trying to build a mono wheel 2x72 grinder. It would just use one wheel and the belt would slip over it. When turned the wheel would expand and lock the belt into place.
Click to expand...
That's a tuffy.... i would imagine anything that could expand with rotation would compress with pressure or torsion. The belt would most likely run off the side under load. Interesting project, though... git er done, boys!
 
This was our original plan was a cut expanding rubber wheel. Most cut wheels are 40-60 durometer. But the company I have been talking to said thy could do 70 if I kept the rpm above 1100 and around 1500 max. My next plan was to do a normal contact wheel and have a slit in the rubber. There would be a tension clip that would pull the belt down into that slit. If done right I don’t think you would notice much of a bump.

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I m ordering new timing belt to try it .I change millions of timing belts but never interested in specification ....I come to this data for this belt .......
HTD 1280-8M 160 Teeth Timing Belt Replacement
Performance：Tensile strength ≧300N/mm,Reference Tension: 240N/mm(Elongation≦4%), Hardness 75±5
Click to expand...
On which hardness they mean ? Duro hardness ?
 
Sometimes delaying the start of a project is good thing . Today I worked on one motorcycle /changed the chain and sprocket / and I get one idea . . . :) What if I make tracking wheel immobile ? I mean ,tracking wheel to work only for adjust tracking on belt NOT + as device for tension on belt ?
For tightening the belt I will use contact wheel ,which is in same time DRIVE wheel ? Something like in the drawing ?
Yellow is housing , red is part where sits axle of contact wheel , blue is axle of contact wheel and 1 is position loose and 2 is tightened belt?
Can not be simpler then this , what do you think guys?

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