what belt?

Discussion in 'Machine Modifications' started by blighty, Jul 20, 2012.

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  1. Jul 20, 2012 #1

    blighty

    blighty

    blighty

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    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?
     
  2. Jul 21, 2012 #2

    Tin Falcon

    Tin Falcon

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    like you said bridgeports use V-belts and the little x-2 pulley conversions use v belts.
    Tin
     
  3. Jul 27, 2012 #3

    terrywerm

    terrywerm

    terrywerm

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    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.
     
  4. Jul 27, 2012 #4

    velocette

    velocette

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    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
     
  5. Jul 27, 2012 #5

    chipenter

    chipenter

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  6. Jul 27, 2012 #6

    blighty

    blighty

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    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
     
  7. Jul 27, 2012 #7

    velocette

    velocette

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    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
     
  8. Jul 28, 2012 #8

    ninefinger

    ninefinger

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    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...:D

    Mike
     
  9. Jul 28, 2012 #9

    chipenter

    chipenter

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    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 .

    P1000196.jpg
     
    bazmak likes this.
  10. Jul 30, 2012 #10

    blighty

    blighty

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    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.
     
  11. Jul 30, 2012 #11

    velocette

    velocette

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  12. Jul 31, 2012 #12

    blighty

    blighty

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    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?
     
  13. Aug 3, 2012 #13

    blighty

    blighty

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    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 :)
     
  14. Oct 6, 2012 #14

    blighty

    blighty

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    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 :D

    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:confused:
     
  15. Sep 29, 2014 #15

    blighty

    blighty

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

    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 :confused: 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:confused::confused:.

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

    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.
     
  16. Oct 12, 2014 #16

    blighty

    blighty

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    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.
     
  17. Oct 12, 2014 #17

    Omnimill

    Omnimill

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    Yep, I've bought most of my machine belts from Halfords!
     
  18. Oct 12, 2014 #18

    Cogsy

    Cogsy

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    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.
     
  19. Oct 13, 2014 #19

    blighty

    blighty

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    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.
     
  20. Oct 13, 2014 #20

    blighty

    blighty

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    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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