[magudaman]

I have an electric bike I have been working on for some time now and really wanted to convert my first stage of reduction over to a 8mm belt system. I have search all over the web trying to find people who already make 8mm pulleys and sprockets but they are not there or are prohibitively expensive. I can have them custom made but at a very high price.

I am a novice CNC machinist and have been playing with a Tormach 1100 for about 8 months and just started to mess around with solidworks and mastercam. I also have the 4 axis unit that hasn't seen any fun and want to put that to the test. I was planing on purchasing Gearotic Motion to give my the initial tooth profile and extrude out in mastercam.

Ok so finally my question is I would like to cut my own 8mm gt2 pulleys, will these turn out okay for use and function well under loads? Can i get away with just standard square and ball-end endmills since I don't have a hobbing machine.

Any other consideration or concerns I need to take into account?

[mactec54]

magudaman

If you Get the Gearotic motion software, they have the 5mmGT2 & the 8mm GT2 ready to run in there software
the profile would be hard to do with out it

[magudaman]

Well I was hoping to cut it with the fourth axis and I thought gearotic wouldn't dump that out for me. Orginally I was going to purchase gearotic to provide me the dxf of the 8mm design and then put that into master cam to create my gcode.

I am also concerned with finished quality and torque handling of a gear that is not created by a hobbing technique and a ball mill instead.

[surfit]

I cut 8mm cog pulley's all the time. I use a 3/8" wide 3" wheel cutter with the tooth form ground on it. I use a fourth axis to index the number of teeth required one cut per tooth simple programming. It takes two and a half minutes to cut a 28 tooth pulley 1" wide. I will give you contact info for the guy that grinds the tooth form if you are interested. I had no luck finding the actual geometry for the pulleys.


%
O01828 (4GR033-028 REV NC 28-T COG PULLEY)
(J. JAMES 05-14-2009)
(FIXTURE TL0329)
(LOAD SHORT END TOWARDS FIXTURE)
T10 M06(3" WHEEL CUTTER 8MM FORM)
M31
G00 G90 G54 X2.95 Y0. A90. B0. S3000 M03
G43 Z0. H10 M08
M97 P1 L28
M05
M09
G00 G91 G28 Z0. B0.
G90 Y18.
M30
N1
G90 G01 X2.735 F80.
Y-2.5
G00 X2.95
Y0.
G91 B12.857
M99
%

[Zahnrad Kopf]

I will give you contact info for the guy that grinds the tooth form if you are interested. I had no luck finding the actual geometry for the pulleys.

Just curious what he charges for a milling cutter for that.
How much information are you giving him to make the cutter?

I ask, because they are usually hobbed or Wire EDM'd as far as I've seen.

The information for the pulley geometry can be derived from the patents, careful measurements, and some math.

Thanks.

[jeep534]

understanding this is an old thread i am in search of such aa form cutter.

archie =) =) =)

[magudaman]

I got away with cutting my own 8mm sprockets out of 7075 with a 5/32 endmill. Took a while due to the end mill length but they are still working amazingly well!

http://www.cnczone.com/forums/1029228-post103.html