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  1. #1
    Zonko is offline Stainless
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    Default How do YOU get flat belts to do their job ?

    Good evening.

    And the flat belt returns another time...to annoy innocent machinists and enginemen. Ive recently run into some intresting stuff.

    Lets begin with our old camelback ...I need it...because our 1950s work shop drill press won't do what i need, it would chatter itself to hell, got the horsepowers but aint got the beef. (Holes in steel...larger than 1 " ) And the camelback shure as hell goes slower and has a lot more beef. But the boss says...the belts will slip. I say: "something is wrong with the belts. That machine aint have tons of beef because the engineers thought it would only run 3/4" drills...."

    I have not tried this yet, its not urgent at all, but at some point in the next 1-2 month i would like to get this crap drilled.....

    And in case our boss actually is NOT being paranoid about slippage....i think he just forgot to use the belt grip wax.... i will have to fix this mess....

    Now i have just been sawing up a load of firewood with our deutz diesel and a big old circular saw and the fact that this tiny pulley on the saw can slow down a friggin 8 hp diesel quite a bit (may be 6 or 10 hp, not shure, i am bad at remembering numbers, can only store facts in my head) demonstrates that most likely the episode with the camelback is just some stupid misunderstanding or a case of insufficient tension, waxing etc.

    However....I am currently working on a rather big model of a lineshaft system, have a look for yourself :

    transmission.jpg

    And I want to use as much flat belting as possible. Some will be round rubber belting, for large distance low power stuff, and short belts countershaft to woodlathe etc. will be small V-belts, they make em down to 1/4 " and even one step smaller (5mm).

    I have some leather material about 7/8 " wide and i have been fiddling around with it today, like wrapping it around the spindle of our small drillpress to see if i get traction......minimal...bad...pretty much no traction unless i pull at the belt with ridiculous force.
    Now i have not yet used the wax because i did not find the stick today...but still. Old crappy belts always work to a certain degree. But this new material just wont do anything......

    How do i approach this, the leather is not yet spliced so now would be the time to do any surface conditioning etc....

    Regards
    Max

    P.S. Please enlighten me about selpentine belts. I looked it up and they also sell as poly-V ? We call those " ridged vee belts" to give ya a litteral translation of the German word "Keilrippenriemen" . But they have vees, how is that gonna end up working on a flat pulley ?

  2. #2
    Frank R is offline Hot Rolled
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    Quote Originally Posted by Zonko View Post
    Please enlighten me about selpentine belts. I looked it up and they also sell as poly-V ? We call those " ridged vee belts" to give ya a litteral translation of the German word "Keilrippenriemen" . But they have vees, how is that gonna end up working on a flat pulley ?

    Here is the thread I refer to: http://www.practicalmachinist.com/vb...-today-157227/

    The serpentine belts are from automobiles or trucks, they can even be used. They are flat with some v-grooves in them. The side with the grooves is the one you want to use because the rubber is exposed and sticky. The other side is flat but coated and slicker.

  3. #3
    ADFToolmaker is offline Cast Iron
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    I had a similar issue with an old flat belt drive lathe I upgraded. Flat belts were not new to us on the farm, but the short centre distance was. None of the traditional flat belt material worked, or at least not for a decent length of time at the tension required. To be be fair we were supplying a lot more torque than was normal when the lathe was built, around 1920. In the end we used a toothed timing belt from a car engine, inside out using the flat face and really high tension.

    I suspect you have sucess with a flat belt on your 8hp deutz because of the larger centre distance (I'm guessing you have the standard setup with the motor several feet from the saw?) Gravity seems to play a dynamic role in this scenario.

  4. #4
    adammil1 is offline Titanium
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    I don't know if it will work for leather flat belts but one trick I have used for rubber flat belts, I recall using it on my old LeBlonde lathe years ago, as well as on my toolpost grinder is to take some spray adhesive that you can buy at the hardware store and spray the belt with it. I believe the stuff is contact cement or something but usually it lasts for quite some time and when it wears off spray some more. I know on my toolpost grinder the issue was I bought some replacement flat belts from McMaster. They came with a nasty crease in them from storage and wouldn't track. Spraying with the adhesive was all it took to get it tracking and once that happened the belt seemed to warm up a bit and track much better.

  5. #5
    JST's Avatar
    JST
    JST is online now Diamond
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    Flat belts can be opposite to what you think.....

    The leather (or rubber) belts that I have seen grip the best were running on pulleys that were so shiny you could about shave by the reflection. And the leather was run hair side "in", was limber, smooth, and "grippy".

    Works kinda like your hand when it is just "damp enough", on a smooth surface.... that can grip so hard, even with little pressure, that it seems ready to rip your skin off.

    If the leather is too stiff or hard, no go. If there is ANY mineral oil on the surface of the pulley, no go. Leather dressing oil is OK.

    If the surfaces are rough, it will work, but not very well compared to the right consistency of belt on a really smooth pulley. grips like a hundred monkeys when right.

  6. #6
    tinkertoy41 is offline Plastic
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    Check the Home Shop Machinist BB it had a great article on flat belts a few months ago!

  7. #7
    Bruce E. Babcock is offline Cast Iron
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    I have two Prony brakes that I use to measure the horsepower of antique engines and tractors of all types and sizes. The small brake uses a 4 inch belt, and the larger one uses an 8 inch belt. Belt slippage is a major problem: just a slight amount of slippage and the belt comes off one of the pulleys. Over the last 10 years, I have tried many formulations and concoctions. Some people said that Coca Cola was the best, others claimed that steam cylinder oil was the solution. I had a limited amount of success with both.

    For the last two years, I have been using either black strap molasses, or honey. It does not take very much of either one. In the spring, after the belts have dried out all winter, I simply put a small amount of water on them, and they come right back to life. I have been concerned that over the winter vermin might start chewing on the belts to get the sugar, but this has not yet been a problem.

    On two occasions, I have measured over 100 horsepower on 40 inch pulleys turning at 250 rpm.

    I am not saying that this is the solution for anyone else, It is simply something that is working well for me.

    If you are in the Cleveland area, I will have my small brake at the Trumbull County show at Middlefield, Ohio on May 31 and June 1.

    Bruce E. Babcock

  8. #8
    Zonko is offline Stainless
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    I would love to visit you Bruce ...but unfortunately you live half a world away :-)

    Anyways, i thought id give you guys an update. Thanks for the advice, i really liked the honey part and the shiny pulley part.Perhaps im gonna mix the honey with some resin dissolved in alcohol or something like that.
    I have also ordered about 12 bucks worth of very small and quite long serpentine belts (3 of them, got a good deal ) plus 2 small v-belts.
    Will give them a shot too.
    Once i receive that order, i will be resuming work on the whole affair. Ill keep ya all informed on how this works out. Something which should eventually pan out to be a huge tabletop full of lineshafting and tools large enough to do useful work on kinda screams * great museum exhibit, especially for kids* and I am getting more and more exited every time i complete another part.

  9. #9
    L Vanice is online now Diamond
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    59-flat-belt-2.jpg

    Here is how I do it.

    I use this Hardinge 59 lathe every day. I designed the bench and drive over 30 years ago. There is a V-belt from the motor to the jack shaft. There are three leather belts from the jack shaft to the counter shaft. There is a Habasit polyester belt from the counter shaft to the lathe, with a back-side idler for tension. I have never put any dressing on the belts. I have not adjusted the leather belts in about 20 years, when I installed a larger high speed pulley and lowered the jack shaft to clear the ceiling after moving to a new shop. The same belts have been running for over 30 years. The leather belts run with the hair side against the pulleys.

    I think belt dressing is only needed when the belt width and pulley diameters are not correctly designed for the application. Shafts need to be parallel, of course. My counter shaft assembly is from a Rivett 505 lathe which was comparable in size to my Hardinge lathe. I let the counter shaft pulleys dictate the belt width and sized the jack shaft pulleys to match the countershaft pulleys. The high, low and reverse belts are engaged by foot pedals, just as Hardinge designed their counter shafts back in 1903. Rivett used hand levers on their benches, and I prefer the foot pedals. I can lock the belts in place with latches if I don't want to keep standing on the pedal, but I almost never use that feature.n If I were to tweak it today, I would put a three phase and VFD motor on instead of the single phase motor. But it all works as well as one could ask just as it is.

    Larry

  10. #10
    Bruce E. Babcock is offline Cast Iron
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    Quote Originally Posted by L Vanice View Post
    Click image for larger version. 

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    I think belt dressing is only needed when the belt width and pulley diameters are not correctly designed for the application. Shafts need to be parallel, of course.


    The attached photo demonstrates the magnitude of the difference between Zonko's application and mine, and it also illustrates some of the issues that Larry mentioned.

    I have no control over the size of the pulleys that I have to deal with on the engines. Depending on the type of engine, they have ranged from 12 inches to over 40 inches. Also, getting an 8 ton steam engine precisely aligned with the brake can be a challenge, especially when it is not self propelled.

    Bruce E. Babcock
    Attached Thumbnails Attached Thumbnails prony-urbana.jpg  

  11. #11
    L Vanice is online now Diamond
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    Nice Prony brake. I had not seen one since they scrapped the one where I worked. We used it to break truck axle shafts, so it was quite different from one designed to measure engine power.

    Long belts and crowned pulleys help overcome the alignment issue, and a lot of farm equipment managed just fine because of that effect.

    Larry

  12. #12
    MetalCarnage's Avatar
    MetalCarnage is offline Hot Rolled
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    I found this little treatise on crowned pulleys and flat belts a few months ago. http://www.lhup.edu/~dsimanek/scenario/crowning.htm Very interesting.

    -Ron

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