MadModder
Gallery, Projects and General => The Design Shop => Topic started by: Swarfing on March 14, 2013, 06:10:25 PM
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Guys I'm rebuilding a Z axis on my cncmill. I've dumped the gearbox in favor of going down the the 2 step pulley route, VFD on the 3 phase motor. I have messed with htd belt, v belt but never played with Poly V belt?
Poly V is the way i want to go but not sure which would be suitable to use (J, H????). I also want to make my own pulleys as well, preference would be to make a suitable form tool for the job. Plan is to go with 6 groove belt and the pulleys to be 100mm and 50mm steps. Saw stuff about using 11tpi pipe chasers for the job, but I'm a metric sort of guy. Any thoughts please?
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Guys I'm rebuilding a Z axis on my cncmill. I've dumped the gearbox in favor of going down the the 2 step pulley route, VFD on the 3 phase motor. I have messed with htd belt, v belt but never played with Poly V belt?
Poly V is the way i want to go but not sure which would be suitable to use (J, H????). I also want to make my own pulleys as well, preference would be to make a suitable form tool for the job. Plan is to go with 6 groove belt and the pulleys to be 100mm and 50mm steps. Saw stuff about using 11tpi pipe chasers for the job, but I'm a metric sort of guy. Any thoughts please?
I have used Poly-V pulleys on several projects. The last was my CNC when I used a 5 groove belt and a 3 step pulley to give me a range of speeds of approx 200 rpm to 10,000 rpm from a 1hp 3ph motor running at up to 5,000 rpm via an inverter.
Here are a couple of scans of documents from a Poly-V belt and pulley manufacturer.
(http://listerengine.com/coppermine/albums/userpics/10017/Poly-V001Large_zpsca0bac6e.jpg)
(http://listerengine.com/coppermine/albums/userpics/10017/Poly-V002Large_zps6a8581c0.jpg)
For my CNC I chose a 5 groove J section because the belts were easy to come by - they're used widely on lawnmowers so can be picked up from a local DIY store or garden centre.
I hope they're of use.
I can send higher res images if these are too difficult to read.
:beer:
Phil.
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Saw stuff about using 11tpi pipe chasers for the job, but I'm a metric sort of guy. Any thoughts please?
So use 2.309090909 mm pitch chasers
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This is is very helpful and the pics are fine to read. Lawn mower specs is probably a good route, like you said Phil makes it common. John i was thinking i could turn a large radius piece with a thread on the lathe and then cut it up to make a chaser from a bit of round? might give that a go. Just need to work out if i can get that pitch.
Cheers
Paul
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Paul,
I have found that Simtek in Germany make profiled inserts for cutting the grooves:
http://www.premierformtools.co.uk/pdf/EZG24.pdf
It might be worth asking Premier for a price (and hopefully you wouldn't have to buy 10!).
Phil.
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I think i'm going to have a go at making one. Just need to find a gap in the weather now to cast up some blanks :beer:
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Hi fell over this thread when surfing
Poly Vee pulleys have the grooves cut at 40 degrees 2.34 mm pitch.
BSP is 55 degrees pitch this will make for a very poor contact.
Eric
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Thanks for the info Eric, Already received a 11TPI pipe thread tool that will do the job. Did a test cut and it will work out just right.
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Sieg machines use J polly v belts Arceurotrade stock them ,
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Hi fell over this thread when surfing
Poly Vee pulleys have the grooves cut at 40 degrees 2.34 mm pitch.
BSP is 55 degrees pitch this will make for a very poor contact.
Eric
Eric agreed but the belt is rubber and soon adapts.
Back in 1999 I built a pencil sharpener and the cutter ran on poly vee belt, 3;1 step up ratio from a 3,000 rev motor so the spindle does 9,000.
Now don't laugh about it being a pencil sharpener, it sharpens 7,000 per hour and was part of the millennium display in the dome in 2000.
Been running ever since, about 6 hours a day, 5 days a week, so far it's got thru 4 belts and one set of pulleys.
I always think proof is better in practice.
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Absolutely Right this now proves that
everyone in the British Isles now has access to TWO sharpened pencils.
Eric
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Not quite, I still have about 30,000 we ran when doing tests :lol:
Hand them out to schools and play groups etc.
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Big thanks guys, cast the Ali and got them made even though i have to make one of then again.......Note to self, make sure cutting tool is set at correct height or it gets pulled into the work and promptly throws it out of chuck and ruins it.
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Eric agreed but the belt is rubber and soon adapts.
Read that somewhere else Rubber fits all sizes!
Eric
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LOL!...I hope so
I have a belt arriving next week so will see the proof in the pudding. Just need to spend some time fixing the spindle in the head and start to balance things out.
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Hi,
I know that it has been a year+ since this post but I was wondering how your belt/pulley retrofit worked out for you.
I have just finished retrofitting a Southwestern Industries Prototrak bed mill with a MachMotion servo kit. My work included a VFD drive so I no longer need the variable speed pulley system that is built into the machine. I would like to replace that system with a poly-v belt to help reduce noise and increase the spindle speed.
I was wondering which belt you ended up with and where you got it.
Any suggestions would be greatly appreciated,
Thanks,
Randy