3 pulleys 2 belts. finding the right size?

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tonyh

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hey fellas. im after some advice on figuring out belt sizes. yes i know there have been many threads about selecting belts but i haven't found much about a 3 pulley system. first off, my machine:

[WORKCRAFT CH16]


got it for next to nothing as my first machine. it had rusted out internals and a stuck table. got the whole thing disassembled and cleaned (mostly) and everything moves freely. the final thing i need is some belts to get her running. my problem is, as far as i know, this machine uses 2 belts. the centre pulley isn't fixed and can rotate about an arm. the locking mechanism pushes the motor outwards to tighten the belts. how would i go about finding the right size belts?

my initial attempts involved centring the middle pulley and measuring the C-C between each pulley. then i realised i had no idea what i was doing after that.

anyone have any ideas?

Thanks
~Tony

PS: the machine didn't come with any belts and a bit of research has turned up no results for the machine or setting up this kind of system (unless it has a special name that i'm unaware of).
 
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Your set up is identical to my Rockwell/Delta. Don't be worried about getting the belts tight for sizing them. You want them fairly loose to facilitate changing speeds.

The chrome lever is for pushing the motor to the rear and tightening the belts. You are missing a thumb screw that tightens to hold your adjustment. It goes in that threaded hole towards the motor from the tension crank. Should be a mating thumbscrew on the other side. Loosen both, tighten belts, tighten thumbscrews.

Not a bad system really. Time to make SWARF!
 
The first thing you need to do is establish what belt profile is needed. You will probably need a 'L' series belt. Measure the top width of the pulley groove. 'L' series belts have the following top widths.

2L = 1/4"
3L = 3/8"
4L = 1/2"
5L = 21/32"

The length of L series belts is specified as the outside length (cir***ference) of the belt a 3L280 belt will have a cir***ference of 28" and a 3L285 has a cir***ference of 28.5".

You can determine the belt length by measuring around the 2 pulleys the belt is for. Avoid using half sizes (eg 3L285) as these to be scarce like hens teeth.

Cheers Richard
 
thanks for the help fellas. sorry it took me so long to reply. i went down to a local tool shop and showed them the head which was disconnected from the pedestal for repairs, and they pointed me in the right direction. the pulleys i got were and M23 from chuck to the middle pulley and an M24 from the motor to the middle pulley. at first they seemed really tight and i couldn't really tighten the machine, but after a few quick test holes, the belts seem to have loosened up a bit and i can changeover and tighten them excellently.

onto my next problem of the bearing in the head appearing to be busted and the fact that when i put it into the highest speed it seems to accelerate slowly indefinitely :/


Thanks for the help again. ill be back after i do some research ;)
~Tony
 
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