| Author |
Message |
ashewitt
Unregistered guest
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| Posted on Wednesday, February 15, 2006 - 10:30 am: |
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Hi,
Great site.
Could you tell me the diameter of the Timing Pulleys 4605-001 to 008? I would like to run a pair from a geared motor which produces 13rpm (Sadly not for a robot application this time). For the drive belt, the vertical shaft, running from the slave pulley, will be around 292mm from the centre of the motor shaft. Would a Timing Belt 840mm 4606-018 stretch to that sort of length? By my calculation, that would give a diameter of only 267mm, but I am willing to be wrong, if it will fit. Failing that, do you supply the V belts to go with the pulleys further up the page in the pulleys section? Many thanks. Adam |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 136
Registered: 10-2004
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| Posted on Wednesday, February 15, 2006 - 7:05 pm: |
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Hi there,
Thank you, we do try and make the site as friendly and informative as possible.
To find out the pcd of a timing pulley (which is close to the overall diameter), simply take the number of teeth x the pitch of 5mm and divide the answer by 3.14. So, a 30T would have a diameter of 30 x 5 / 3.14 = 47.75mm.
Timing belts do not stretch, they contain steel wires woven into the belt. This means choosing the nearest size belt and adjusting the distance between the motor and driven axle. If this is not possible, try using another adjustable pulley to take up the slack.
Without knowing what reduction ratio you are after, it is difficult to be precise on what size belt you need. Using an example though (perhaps we should add a calculator to our 'calculators' section on the Technobots website) of:
Drive pulley 10T, driven pulley 30T (3:1 reduction) with their centre lines 292mm apart gives a length of (approx) -
(30T circum / 2) + (10T circum / 2) + 2 x 292mm = (30 x 5 / 2) + (10 x 5 / 2) + 584mm
= 684mm In fact it will need to be slightly longer than this due to angles but it is close.
Thus, a 840mm belt would be far too long and the 630mm belt too short. We do intend to increase our range of belt lengths in due course but that wll not help you now.
Sorry, but no other V belts although 'O' rings can be used, you can get 'O' ring kits that you make to the required length. I would not like to say how effective they would be. |
robin fryer
Unregistered guest
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| Posted on Wednesday, September 12, 2007 - 9:22 am: |
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Hi the OD for the pulley
Timing Pulley 10T - Part No: 4605-010
does not appear to be listed could you please email me the out diamter please?
Thanks |
Robin Fryer
Unregistered guest
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| Posted on Thursday, September 13, 2007 - 10:14 am: |
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What is the diameter of the grub screws used to locate the pulleys onto a shaft??? |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 577
Registered: 10-2004
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| Posted on Sunday, September 16, 2007 - 6:18 pm: |
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Robin,
These were later additions to our range and looks like we did not get around to measuring them. I would estimate a 10T would have an OD of 18mm and the 12T about 22mm. Not sure of the grub screw size but probably M3 or M4 but each pulley does come with the correct size hex key.
Apologies for taking longer than usual to reply. |
denis glaser (Dvg)
Member
Username: Dvg
Post Number: 1
Registered: 3-2008
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| Posted on Wednesday, March 26, 2008 - 10:40 am: |
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Can I bore your pulleys out to 9+-1mm? We need to make 4, 500mm bike wheels on two ball bearing bike shafts 2000mm apart turn slowly in air - no resistance, using a motor with a 9mm shaft 1000 from each. Which pulleys - timing or V or other, could I use? |
Admin (Admin)
Board Administrator
Username: Admin
Post Number: 742
Registered: 10-2004
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| Posted on Wednesday, March 26, 2008 - 7:10 pm: |
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Denis,
The ability to bore out a pulley depends on the pulley design and size. If you could give some indication as to which pulley you are considering, we should be able to advise. We can supply both types of pulley but the belt size is a limiting factor for the timing pulley. Belt tension is more critical for V belt drives and of course torque also makes a difference to the pulley selection. If you can expand on your description, hopefully we can help. |
