1. Originally Posted by D-man
OK so im getting round about 96.16mm for one revolution of the pinion.

96.16 divided by 8000 = 0.01202 steps per revolution ???
Wrong way to think about it.
You need steps per mm.
So if it takes 8000steps to move one pinion rotation of 96.16mm, then you divide the 8000 by 96.12, which gives 83.19467554 steps per mm.

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3. Originally Posted by m_c
1.25MOD is 32.69mm OD.
24DP is 1.09" (27.68mm), and 20DP is 1.308" (33.22mm), and 22DP does not appear to be a common size.

So assuming 1.25MOD and me reading the correct number from the chart, gives a pitch of 3.926mm per tooth, or 90.289mm for one rotation of the gear.

Or to assume 20DP, it would be 91.7194mm per rotation.

Are you sure it's a 23 tooth gear?
As even working backwards from 96.16mm, it doesn't fall on any common tooth size.
That's assuming I'm not making a complete hash of the calculations.

Off course, easier option would be just to measure the distance over as many teeth as possible and calculate the tooth pitch that way.
I'm fairly certain they are the right numbers, I will check again in the morning mate and come back to you.

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4. Originally Posted by m_c
Wrong way to think about it.
You need steps per mm.
So if it takes 8000steps to move one pinion rotation of 96.16mm, then you divide the 8000 by 96.12, which gives 83.19467554 steps per mm.
I did try it that way but didn't want to mention in fear of looking daft, as I calculated it as it was written

Cheers for the help lads much appreciated.

Attached a few pics just in case I've missed or got something wrong

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5. Originally Posted by D-man
OK so im getting round about 96.16mm for one revolution of the pinion.

96.16 divided by 8000 = 0.01202 steps per revolution ???
Nah wrong got it wrong.

You now have distance pinion travels for one rev which is 96.16 but you have 5:1 ratio so this drops to 19.232 for one rev of the motor which is the affective pitch. So now simply divide 1600 by pitch to get the steps per mm ie: 1600/19.232 = 83.194 steps per mm

Doh didn't see MC done it.!
Last edited by JAZZCNC; 17-03-2017 at 08:39 PM.

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7. Defiantly a 23 tooth pinion

32.82 Dia Pinion (digital Gauges so may change each time lol i will also try a normal set in case these are off.)
93mm Travel now lol (Hard to get to the pinion to mark it, but i would rather go with this measurement)

8. OK so now im confused. i punched these numbers into software, however, when I want to move 50mm (In MDI) im getting something like 267mm when marking the gantry and measuring

9. OK, go back to basics.

Set the steps/mm to 100, mark the big pulley/pinion, and command a move of 80mm (8000 steps).
Does the pulley/pinion move one complete revolution?

10. Originally Posted by m_c
OK, go back to basics.

Set the steps/mm to 100, mark the big pulley/pinion, and command a move of 80mm (8000 steps).
Does the pulley/pinion move one complete revolution?
Ok that was just over quarter of a turn

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11. With the same 100 step/mm setting, try a move of 16mm and see how far the motor itself turns.

12. Just thinking of possibilities:

Are you sure it only rotated 1/4 turn? Not 1 1/4 or 2 1/4 etc,
as you previous test seems to indicate too much rotation not too little i.e moves 267mm instead of 50mm.

Also are you sure the leadshine driver pictured (1600 steps/rev) is the one driving that motor?
Could one of the others be driving it and have different microstepping settings?

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