16 tooth pulley HTD5 15mm on a 14mm shaft

[dsc]

Gents,

I'm planning to mount a 16 tooth pulley (HTD5 15mm) on a 14mm shaft (Nema 34 motor), but it seems that the maximum bore size I can machine in the 16 tooth pulley is 12mm:

16 Tooth HTD5 Pulley (16-5M-15F) [HP16-5M-15F] : Beltingonline.com, Supplier of power transmission and conveying products (http://www.beltingonline.com/16-tooth-htd5-pulley-16-5m-15f-7774)

I can upsize to an 18 tooth pulley, but it screws up the pulley ratio as I'm using a 48 tooth pulley on the other side (48:16 gives 3:1, but 48:18 gives 2.6667).

Any ideas whether I can get a 16 tooth pulley HTD 5 for a 15mm belt with a beefier bottom like this:

http://makemendel.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/o/p/optimized-t2.5_5mmbore_16teeth_3.png

Or is that not a possibility?

Regards,
dsc.

[irving2008]

Do you really need a NEMA34 motor?

[dsc]

Hi Irving,

I might not need to in the final design, but for testing purposes I need a Nema34, I simply don't know whether a less powerful motor can handle what I want it to do. I haven't been able to find a motor smaller than a Nema 34 with the same torque curves as a Nema 34 8Nm (which sort of makes sense to be hones).

Regards,
dsc.

[John S]

Plenty of meat there for a 14mm shaft.
just drill for the grub screw from the bottom of one tooth on the pulley and not the boss.

Probably pay to put a keyway in and one in the motor shaft, asking a lot for a grub screw to handle 8Nm

[dsc]

Hi John,

thought so too, but then I did some calcs and it doesn't seem to leave a lot if you put a keyway:

- outer dia of the pulley is 24.32mm, r=12.16mm. HTD5 belt is 2.08mm deep, I'm guessing same is true for the pulley teeth, which means the internal 'meat' on the pulley is 12.16mm - 2.08mm = 10.08mm radius

- keyway in the shaft is 5mm wide, 3mm deep, spec says (found somewhere on the web) to cut a 2.3mm deep keyway in the pulley

The above means a keyway cut in the pulley will leave 10.08mm - 7mm (shaft radius) - 2.3mm = 0.78mm of material.

Unless of course I'm cocking it up somewhere.

Grub screw in the toothed area will give me roughly 3mm thickness for the grub screw to hold on to. Probably enough but as you say not plenty for a lot of torque.

Regards,
dsc.

[John S]

How about 20 / 60 ratio ?

[dsc]

I'd like to, but I think the only option for me would be a flange-less 60 tooth as I only have 50mm radius around the driven side. Not ideal as I was planning to use a Drivelock bushing and those I believe are suited for taperlock ready pulleys, which have flanges and don't come in 60 tooth versions (only 56 and 64).

Regards,
dsc.