Expando drum issue

[redrockrods]

I bought a new 8" expando drum for my arbor and am having a problem with getting the 3m Trizart belts to stay in place. the belt slips and slides around when the arbor is running and it doesn't seem like the drum is expanding at all to hold the belt in place. Regular silicon carbide belts are a tight fit on this drum. Any ideas on what the problem could be? maybe my arbor isn't spinning fast enough for the drum?

[Bluesssman]

When you say the regular silicon carbide are a tight fit but the 3M Trizart belts are loose, it makes me think there is a belt size issue. Also, if I am not mistaken the expando drums can only be put on one way to work correctly.



Gary

[redrockrods]

I'm wondering the same thing. I've oriented the drum on the arbor according to the sticker with the arrow indicating direction on the drum, but maybe the sticker was misplaced? I'll flip the drum around when I get home and see what happens. 

[Taogem]

I battle the same problem even with just the silicon carbide belts.. Still have not figured out if buying from one supplier compared to another results in slightly different sized belts.

Some fit really tight on an 8", and some fit loose..

Seems like I have to compare supplier to each individual drum or something..

Here is how you want your drums oriented..

[redrockrods]

Thanks for the pic George. I played around with it this evening and had no luck one way or the other. the 3m belts are just too big.  I had some problems with a few of the carbide  belts moving too...I'm getting a little bummed out with this used equipment I purchased, seems to have nothing but problems.

How can I figure out the RPM generated by my motor and pulley? It's a 1/4 HP motor, 5/8" shaft, 2" pulley on the drive shaft going to a 4" pully on the arbor. I'm wondering if I'm not getting enough RPMs to make the expando drum expand.

[Taogem]

How can I figure out the RPM generated by my motor and pulley? It's a 1/4 HP motor, 5/8" shaft, 2" pulley on the drive shaft going to a 4" pully on the arbor. I'm wondering if I'm not getting enough RPMs to make the expando drum expand.

Here ya go.. Come back if your still having problems after making sure about the rpm's

[Taogem]

I'm getting a little bummed out with this used equipment I purchased, seems to have nothing but problems.

I do understand the frustration ..

I replaced three of the drums on my multi wheel unit right away..

If yours are sliding off the drum while in use, then hate to tell you, but likely need new drums..

When you look across the surface of each.. Are they perfectly flat ? Does the rubber look rotted around any of the slots.

Here is a short thread showing my similar issues, and comments from other members about it.

You can skip right on over the part showing me with my drum on backwards ! 

[redrockrods]

Thanks for the calculator.  According to that site, my arbor is only working at 865 RPM. Anyone know how many RPMs an arbor is supposed to turn at? The expando drum says not to exceed 1800 rpm, so if I get a 4" driving pulley for the motor, that should put the arbor right around 1725.

[Taogem]

I have both my "driven" (drum arbor) and "driving" (motor pulley) on 2.5 " pulleys. With a 1725 rpm motor which works out to the same 1725 rpm for my drums.

I am guessing that your right about thinking your drums are not running fast enough resulting in the expando drums not expanding.. 865 is slow.. Slow for cabbing too..

[Taogem]

What are your pulley size options?  Is your motor a 1725 rpm?

I am heading out the door to take the grandkids back to the city..

Maybe someone else will help or I will be back in a couple hours..

[Bluesssman]

I agree with George, spinning your expando drum at a higher speed will certainly make cabbing much nicer. I am not sure it will eliminate your problem of slipping belts.

Do you know the rpm of your motor. The most common are 1725 and 3600. This knowledge will be very important when figuring what pulley ratios to use. Also, when you do change pulley sizes be sure to take into account the change it will make on the length of the belt. You may need a new belt if you do not have enough adjustment to work with on your arbor.


Gary

[redrockrods]

The motor runs at 1725 rpm.  would it be better to change the size of the driving pulley or the driven pulley?  The motor is bolted onto the back of the arbor, I'm not sure how much room there will be to move  it around to adjust the lenght of the belt. how difficult is it to change the belt out?

 I looked online and I think I can get new 2.5", 3" or 4" pulleys for the 5/8" motor shaft, but I don't know what is avalaible for the driven pulley. the arbor is 3/4".

[redrockrods]

As I break down my machine for cleaning and inspection, it looks like I"m going to need some new spacers to put between wheels. What can I use for spacers? will regular old pvc pipe cut to length work?

[Bluesssman]

Good, your motor rpm is perfect. I would use a minimum of a two inch pulley on an application. This allows more belt contact and eliminates the belt sliding. What size is the pulley on the arbor? If it is at least 2 inches then change the pulley on the motor. Could you post a picture of the motor adjustment.

As far as spacers, yes you can use pvc for spacers, but be sure the inside diameter of the pvc is 3/4" and the ends need to be sanded flat and square.


Gary

[akansan]

Do you have a Tractor Supply or Orshelns out where you are? I can get pulleys and belts at my local places for just about any shaft width.

I've used both "black" pipe and PVC pipe for my spaces, in addition to the nice ones that came with my machines.  Anything works, really, including stacking a bunch of washers next to each other.