# what belt?



## blighty (Jul 19, 2012)

i have owned an RF45 for 3 odd years now and my ears can't take them ruddy gears any more. so for the sake of my hearing i think it's time for a belt mod.

but what sort?

i have seen many types of belts being used..... apart from one.... the common V belt. there is probably a reason for this, but i cant figure it out what that may be. it might have something to do with efficiency. but saying that, Bridge Ports and such other milling machines have been using V belts for years and they seem to do all right. 

at the mo i can think of three belt options.
1 V belt
2 toothed belt (5mm pitch)
3 poly V belt.

i would like to go with the poly belt, but at the mo i can't find a place on the net (UK) that sells them in X length. toothed belt would be the next one and the V belt would be the easiest as the pulleys are not that hard to make.


any ideas/ thoughts?


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## Tin Falcon (Jul 20, 2012)

like you said bridgeports use V-belts and the little  x-2 pulley conversions use v belts. 
Tin


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## terrywerm (Jul 26, 2012)

A few other points to consider: timing belts will make some noise, especially at higher speeds.  As a rule, V belts will run more quietly and they are available just about anywhere.


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## velocette (Jul 27, 2012)

Hi My sypathy with battered ear syndrome I have converted my X2 mill to belt drive.
Much more peacefull now.

I have had a quick look at the specs for a RF 45 mill a very nice peice of machinery 
One question springs to mind Have you changed the oil in the gearbox since new as some times the original oil leaves a lot to be desired.

Have you considered fitting a DC variable speed drive as single phase AC motors do run roughly.

I did this conversion on 10 X 27 lathe and the drop in noise level was very notable.
To improve even more fitted an oil pump to deliver oil to a gallery 
in the gearbox lid to flood all the gears and bearings with about a half litre a minute of oil.  
Check this link it was a great help

http://www.homemodelenginemachinist.com/f16/single-phase-motor-chatter-17383/

you may want to do more research into a belt conversion 

This is my attempt on an X2

http://www.homemodelenginemachinist.com/f28/x-2-mill-belt-drive-alternative-15157/

Keep us all posted please

Eric


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## chipenter (Jul 27, 2012)

I have been using 
polly V belts for some time now , made pulleys and find they are much easer to change and quiet , the pulley were simple to make to .
http://www.solenttools.co.uk/p0/poly-v-drive-belts/363050.htm UK supplier .


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## blighty (Jul 27, 2012)

velocette....

yep, the oil was changed out about 9 months a go. i rang the guys where i got it from and they even said "don't use the oil recommended, use this stuff" can't remember what "stuff" was exactly, but it did quieten it down from the noise of really big tank to the noise of a big tank. 

motor wise....

i nice new 2.2kw 1400rpm 3phase motor turned up last week and yesterday the VFD turned up to run it. with the gear ratios i have chosen should give me 445rpm/ 1100rpm and 2150rpm/5000rpm. as you can see i have a gap in the middle of 1000rpm that i can't get with just 2 gears. that why i thought of v belts, so i can get another gear in the with the amount of space i have.

but now with chipenter link (thx) i might change my mind about the v belts and go with poly......


chipenter...

how wide are you poly v belts? as this will help my a lot in deciding on how many gear ratios i can have.


thx for all your input gents


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## velocette (Jul 27, 2012)

Hi 
That is another alternative to variable speed as a three phase motor will run much more smoothly than single phase.
PJ Poly Vee belts are 2.34 mm per rib X 6 ribs + 1 rib 16.98 plus lands 

Say 20mm wide pulleys. The belt width is only approximate for the 2.2 kw motor.

As you will appreciate That the bigger the diameter of the pulleys the less 
the loading on the belt.

Keep us posted with pictures too for being a NUT on conversions and modifications get great pleasure in seeing how other tackle them

Found this surfing not sure if this is the same as your mill

http://www.cnccookbook.com/CCMillBeltDrive.html

It may help

Eric


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## ninefinger (Jul 27, 2012)

I too feel your ear drum pain as I have an MD-001 (the slightly bigger brother to the RF-45 otherwise known as an Industrial Hobbies mill clone).  I have been looking at how a few other have done this on other forums and the ones that look the nicest have been done with the poly vee belts.  Typical is 2 sets of pulleys with a high range and a low range, usually giving up a fair amount of low end torque over the gears in favor of much higher top end (typically 2x original), with a big 3 phase motor and VFD.

I "think" that the reason plain old V belts aren't used is to do with the pulley size.   If you want to keep things compact (ie in the original head envelope)  then you need to use small diameter pulleys.  That in turn means a smaller cross section V belt and lower overall power transfer.  The poly vee belts are better in this respect (pulley size to power transfer) and also require less pulley movement to effectuate a change of ratios versus the deep groove of a v belt.

Do please keep us informed of your choice - I may one day get off my duff and do something about the noise and when I do I want to be able to copy somebody, not blaze a trail...

Mike


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## chipenter (Jul 28, 2012)

I had two belts over 30 mm wide so turned them inside out, and cut them into 4 grooved belts with a Stanley knife ,made the pulleys with 12mm wide steps .


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## blighty (Jul 29, 2012)

chipenter.....

just been look at that web site for the poly belt. seems strange that all types of poly belts are out of stock. i'll give them a buzz when the time comes.

velocette...
"PJ Poly Vee belts are 2.34 mm per rib X 6 ribs + 1 rib 16.98 plus lands"

if you have a look here http://www.solenttools.co.uk/p0/poly-v-drive-belts/363050.htm their a bit lite on info about there belt's, you just buy them by how many groves you want. do you think it would be the same dimensions you gave above?

if that is the case then 7 or 8 grove belt will do for me. plus i can get three pulleys/gears in the amount of space i have.


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## velocette (Jul 30, 2012)

Hi this is the files that I use for "Design And Build" Poly Vee Drives 

A lathe, X2 Mill and Two drill presses Plus the power feed on the Lathe Leadscrew

Hope this can help 

I Can usually have them EX Melbourne delivered to the local New Zealand Agent in less than 5 working days

Eric 

View attachment polydrive ribbed.pdf


View attachment pulleys_polydrive.pdf


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## blighty (Jul 31, 2012)

right then, i have done some number crunching with all the info you guys have given me and i have come up with this......

if i go for a 7 tooth belt that should give me an 18.72 wide belt, that should be ok to give me three pulley ratios.

low, 70mm / 154mm   2.2:1
mid, 112mm / 112mm  1:1
high. 154mm / 70mm  1:2.2
belt length is about 660mm...... worked that lot out from here http://www.blocklayer.com/pulley-belt.aspx

i can run the motor i have from 35hz (it can go as low as 20hz but the motor will need forced cooling) up to 80hz. at 50hz the motor will turn at 1400rpm. so in theory i should get a speed range of....

low 445rpm / 1028rpm
mid 980rpm / 2240rpm
high 2156rpm / 4928rpm


sound good to you guys?


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## blighty (Aug 2, 2012)

ruddy typical, 

everything is in to start with the belt conversion. i have the motor, VFD and the poly v belt came in the post today. with that i thought i best start machining the motor plate. so i stuck a bit of Ali on the mill and hit go. 20 minutes into it it all goes quiet, as if it wasn't cutting any more. sure enough the DRO's in Mach are moving ,but the cutter isn't

turns out that over time there has been some rubbing of two wires near the motor end that finally shorted and took out a Gecko drive

bad news is, i have to send it back to California to get the FET replaced. i'm guessing i wont get it back for a few weeks. not 'cos they will take that long to fix it, but UK customs will look after it for a week or two just for the fun of it.

good news.... they are fixing it for free


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## blighty (Oct 5, 2012)

bit of an update........

bit of bad new when it came to the gecko drive. when they looked at it they found two FET's gone and a very damaged circuit board. in other words not worth fixing. so a £112 later a nice new one turned up 

with the new drive fitted i could then carry on with the motor plate.

also, i have turn up four of the six pulleys. and as the norm with me i didn't have the right size ali to turn up the 154mm di pulleys. the two chunks of ali to make them should be turning up next week.

then i need to put the 8mm key way in three of them and machine the 8 6mm key ways in the other three.

i'll post some pics when i have turned up the two remaining pulleys.

then the fun bit starts........ putting it all together


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## blighty (Sep 29, 2014)

ruddy hell!!!!! 2 years later and i have finally done it 

took a bit longer then i was hoping for. had some problems with the replacement gecko. as the 201 blew i went for the 201x, newer and better. turned out that wasn't the case. the drive was on the x axis and when said drive stopped for 30 odd seconds the stepper would jump a few steps. took about a year to figure this out (didn't use the mill a lot). got the 201x replaced with the older more expensive 201  and all problems went away.

then a year shot by.

that leads up to yesterday. i thought now or never. so i ripped the mill apart and threw the thing back together. pushed start on the old VFD and all the lights went out.

20 minutes later, after pushing buttons on the VDF the lights stopped going out and the motor started to turn

so recap of speeds........
low 445rpm / 1028rpm
mid 980rpm / 2240rpm
high 2156rpm / 4928rpm

no low
mid 1000rpm / 2400rpm
high 2200rpm / 5100rpm

not to bad.......

noise wise........

bliss!! no more ruddy gears. the motor doesn't really make any noise, just a slight hum. the spindle has that dry bearing noise, that starts to get a bit loud when above 3000rpm, but its no where near the noise of the gears. might have to look into some different bearings.

cutting........

i have only done a few test cuts, just playing kind of thing. well happy with the results. its still a bit heath at the mo. the motor could do with being dropped 31.29mm ish. that will lower the pulleys on the spindle, should take some of the load of the top bearing. then make new (nicer) motor mount...... isn't hindsight great.


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## blighty (Oct 12, 2014)

been looking into this bearing thing.

turns out that the RF 45 has roller bearings holding the spindle. from what the net/forums say these are good for rigidity not so good for speed. near enough all the threads i have looked at have recommended 

Kit10017	7207 Nachi Angular Contact Bearing :Steel Cage:C3:35x72x17	
Kit10016	7206 Nachi Angular Contact Bearing 30x62x16:Steel Cage:C3:

couldn't find them in the UK bu there was a place in the US that did them. $70 later there on there way. 

its been over a week with no show. hope they turn up soon, dieing to get the hammer out for some precision bearing fitting.


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## Omnimill (Oct 12, 2014)

terrywerm said:


> As a rule, V belts will run more quietly and they are available just about anywhere.



Yep, I've bought most of my machine belts from Halfords!


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## Cogsy (Oct 12, 2014)

blighty said:


> Kit10017    7207 Nachi Angular Contact Bearing :Steel Cage:C3:35x72x17
> Kit10016    7206 Nachi Angular Contact Bearing 30x62x16:Steel Cage:C3:


 
Nachi are a good brand, there are better but they'll be fine. For really high speed phenolic (plastic) cages are the way to go, not just for rotating mass but for grease retention, but this application wouldn't see super high speeds so steel cages will be fine.

As for the C3 bit, that designates the internal clearance class of the bearing. C3 and above is more than normal, C2 and below is less than normal. However, single row angular contact ball bearings cannot have individually set internal clearances and therefore do not exist in C3 designation. There are matched sets available that when used together will have a predetermined preload or clearance inbuilt. They are often used as spindle bearings on (expensive) lathes and are generally set up with carefully calculated preload for maximum load capability and virtually zero runout. You have not ordered a set of these.

So long story short - there's nothing special about the Nachi brand and your local bearing supplier could have supplied a reputable brand with exactly the same specs. The price looks a bit on the high side but I've been out of the game for a while and that might be an acceptable cash sale price. I know they'd go for around $10-15ea to an electric motor repairer. And lastly, anyone who tries to sell you C3 single row angular contact bearings has absolutely no idea about bearings.

Having said all that, I'm sure your conversion will go well, I just wanted to give you a bit of information.


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## blighty (Oct 12, 2014)

why oh why do you find this lot out after you buy stuff.

$20 was for posting. good info Cogsy, i sort of took the easy way out when it came to the bearings. yes, i could of gone to my nearest bearing place, but didn't know what i was after. and as these bearings showed up a lot on the forums i thought i would follow suit.

bit of luck they will turn up in a few days. ill post some pics when they do.


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## blighty (Oct 12, 2014)

Omnimill said:


> Yep, I've bought most of my machine belts from Halfords!



thats what started this thread off. i have seen a lot of belt conversions and only a few have V belts. most went with V polly as did i. looking back the pulleys are a pain in the *** to make, they take up more room than a normal V belt and as far as i know you cant get them in Halfords.


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## Omnimill (Oct 13, 2014)

The last belt I bought for my milling machine was not in stock at Halfords at the time so I went to a local Motor factors and got one there. Most towns seem to have a Motor factors if you do a search.

Vee belts hold up well to speed change abuse - belt slipping between pulleys, not sure how well it would work with other types. If you're not belt slipping then just get the easiest available.


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## blighty (Oct 16, 2014)

now that i have paid Mr Customs the 46% "because we can tax" tax,i now have my bearings.

should of put something next to them for a bit of scale:wall:


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## Niels Abildgaard (Oct 17, 2014)

Why three belt disc sets?
My Lathe VFD is used from 8 to 80 Hz regularly and I have cut thread in direct drive at 4 Hz.


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## blighty (Oct 17, 2014)

Niels Abildgaard said:


> Why three belt disc sets?
> My Lathe VFD is used from 8 to 80 Hz regularly and I have cut thread in direct drive at 4 Hz.




i was recommended by the guys i got the motor from not to run the motor any lower then 35Hz. lower than that i would need forced cooling. any more than 80Hz the bearings wouldn't last to long. as to how long and compered to what i don't know..... so thats why i went with 3 sets.

but in the end, i had some problems turning up the last 152mm pully, so i just went with the 2 in the end.


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## blighty (Oct 20, 2014)

right the.....

done a bit of machining over the weekend and noticed a few things.

the lower end of the spindle gets a bit hot. it has been doing this for a bout a year, even before the belt change. when running at about 2000 rpm it gets really hot. and this is only after 5 min of running. i put this down the the bearings. so i thought i would change them out for the nice new ones. also when the spindle gets above 1600rpm there is a loud knocking noise. i thought this would be fixed with the new bearings.

done the change today. ran the spindle up to 2000rpm. it seems the temp problems have gone but the noise is still there. i think it may be coming from the top set of bearings. im also thinking it could be the way have mounted the pulleys. the pulleys on the spindle side are mounted to the spindle directly. as there is a bit of play between the spindle and the drive it may be slapping around in there. think i might have to redo the pulleys.


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## blighty (Jun 8, 2015)

doesn't time fly........

just a recap...... when i first did the mod i mounted the pulley's strait to the spindle. this i think was making the banging noise. a few months back i took out the spindle drive thing and machined off the gear. then turned it upside down and put it back in. (bit hard to explain with no pics, but im at work at the mo and really board) then mounted the pulley on to this. so now the motor is turning the drive that turns the spindle (like before i did the belt mod) and not the spindle it's self.

much better, but there is still a slight banging noise. next thing was to put a thread and a nut for the top end of the drive/pulley bit, that when  done up will pull all the slop together. did this at the weekend..............banging noise still there.:wall:

i took the spindle out and ran the motor. dead silent. all your could hear was the motor and a slight hum from the bearings holding the drive. put the spindle back in and the noise is back. (should of said....... the noise is coming from the top end i.e the drive/pulley) thinking it might be a lining up problem, i took the head apart and hammered out the dowels that line the top of the head up with the bottom. put it all back together, nipped up the screws and turned the motor on......... noise almost gone. i think with a bit of persistence i should get it lined up.

from seeing other belt mods on the net, i don't recall ever seeing this sort of problem. they all seem to be real quite from the word go.

i will stick some pics up. the above might make more sense.


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## DJP (Jun 8, 2015)

Have you checked run out of the pulleys? They can stretch and release a belt on each revolution and that causes noise.

My cut off band saw has this problem but I ignore the banging as it's a crude machine doing a crude job. Adding a few more set screws to the bad pulley might help but it's a low priority repair.

For a milling machine I have to agree that quiet is good.


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## blighty (Jun 9, 2015)

DJP said:


> Have you checked run out of the pulleys? They can stretch and release a belt on each revolution and that causes noise.
> 
> My cut off band saw has this problem but I ignore the banging as it's a crude machine doing a crude job. Adding a few more set screws to the bad pulley might help but it's a low priority repair.
> 
> For a milling machine I have to agree that quiet is good.



dont think the pulleys are out, the id and od was machined at the same time with out removing the pulley from the chuck. the od is a sliding/push fit, but there is no reason why i shouldn't check them.


pic time......... first i would like to apologize for the crap job i made of the Paint.jpg's

the pic below are how the set up was.
when you do a belt mod, you take the drive out and turn it upside down. you then put the pulley on and lock it all up with a nut.


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## blighty (Jun 9, 2015)

to the real thing.....

i know its all a bit heath at the mo, but once iv'e sorted it all out i'll make good and proper.

as you can see the spindle is stuck out the top of the drive. when you remove this and start the motor all is quiet. this is why i dont think the is any thing wrong with the set up in the pic. you get the noise only when the spindle is put back.

the spacer in the second pic is where the other pulley will go.

as i said, it does seem to of made a difference after i took out the dowels. it may just be a case of things being slightly out of alignment.


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## blighty (Jun 30, 2015)

well........ shes all up and running.

i think the noise coming from the top pulleys was a lining up issue. for those that don't have an RF45 there are two dowels the line up the top cover with the body of the head. seems they where a bit out. so i took them out, put the cover back on and with the use of an alignment tool (big hammer) got it all lined up. no more noise 

findings........

with the other pulley fitted top end speed is just shy of 5000rpm @1.3gg's
works out that the ratio ended up 2.18 and not 2.2 like intended. 

cutting.....

got some numbers (speeds and feeds etc) and gave it a go.
with the stated power numbers came back with....
6082 T6
12mm end mill (1/2"ish)
3640rpm
22mm doc
1840mm'min (72in/min)
1.7mm step over (0.066")

cutter hit the T6, a stream of ali shot out from the cutter, just like the big boy cnc's like you see on YouTube then the cutter slowed down and stopped! mill then turned into a shaper for a bit

if you turn the rpm up it just get louder cutter still stops.
if you turn the feed down cutter dont stop, but your now going backwards, so whats the point of speeding it up in the first place.
ended up with 1mm step over works a treat.

to cut at them speed, looks like i need to do two things. 
1. get some more gg's.
2. less of a steep over.

again, going over some numbers it seems i wont need any more than 4000rpm and that would be for the smaller cutters 6mm and below. but saying that it will still be cutting 4 times faster than it used to. 

if i remake some pulleys around the 1.78 mark that should give me the 4000rpm. that would also mean i can run the motor at 80hz should also get me up the 2gg's mark. then it might be able to cut at the 1.7mm step over.

or i could try slot cutter (2 flutes) 

other problem is the amount a swarf it makes and trying to clear it. my flood coolant wasn't up to the job. i had to get in there with the air line and blow it out the way. i can either find a coolant pump that spits out a million gallons a minute or go the way of the mist coolant.

think i will go with the mist as don't want the man cave flooded.


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## blighty (Jun 30, 2015)

just had a thought. it might be a VFD setting that's at fault as to why the spindle stopped.

thinking about the old set up...... 1hp motor, turning the spindle at 1700. that works out to be .8hp ish. in that set up the cutter would explode, snap or throw the work out the vice, but never once has the cutter/motor ever stopped.

maybe there is a setting in VFD that sets the amps.


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## blighty (Jun 30, 2015)

just found something out about the vfd i have..... there is a button on it that once pushed will show the amps the motor is pulling.

3hp motor running at 80hz @2240rpm =1.4amps.

1.4 amps that cant be right, ill run a tool path tomorrow (under load) and see what it says.


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## blighty (Jul 5, 2015)

done some more playing with speed and feeds........

12mm cutter
22mm doc
3mm step over 
3800rpm
900mm/min

amp read out on the vfd goes up to 6.7 amps when cutting at that speed.
seems to like 2mm step over better @1100mm/min

this is all grate and all, but now i have another problem..... HOW MANY CHIPS DOES THIS THING MAKE

when its not throwing them all over the work shop, there jamming up the cutter. at the mo i have have been flooding it with coolant and also giving it a blast with air.

so i'm now looking into the pro's and cons of mist coolant or "very" flood cooling.

flood cooling seems to be the easiest, but saying that, it seems you need around the 8000lt/min to blast the chips out. i have seen a few people on the old intermerwebnet using fish pond pumps (i have been using one for years, but its only 500lt/min) i have found a pump that comes in at 10'000lt'min and around the £100 mark. thats the easy bit. the hard bit is getting said 10'000lt/min back in the coolant tank.

mist... is all down to the compressor. i have found a few that are up the job. most misters need 10 to 20 psi @200lt/min or over 5cfm. but so far i haven't found a definite answer to how much you need. plus the quietest compressor i have found is 74db. 

thought this hobby machining was meant to be fun:wall:

and the compressor i have now just took a nose dive:wall::wall:


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## mcostello (Jul 6, 2015)

Your purchases are just starting-- making chips like that You will have to get a chip baler, forklift to move all, big truck to take chips to the scrapper,etc. Rof}


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