belt and pully question please help .

[mjs79]

hello cnczone
im in the process of gathering the needed parts to start my cnc mill build .i picked up a 24" travel actuator for my y axis . the actuator has a timming pully thats on the end of the lead screw . the pully is a dia if 1" 7/16 and has 25 teeth , and 7/8" wide contact area for the timimg belt .
what i need to find out is what belt would i use ? and what size pully should i use on the stepper motor . im guessing a 2:1 ratio would put the stepper pully at 12-13 teeth .

are the timming belts standard size ? or is there different belts for different gear pitchs ?. i hope this make sense to you , sorry i have never had to use these belts before .
any info to help me get the correct parts would be GREAT .
thanks cnc zoners for all the useful info i have read on this site .
cheers
mike

[Coogrrr]

for pitch and belts and pulleys this is the site. SDP-SI.com as thye have all you need. As long as the pulleys match in pitch and match the belt you can do a 2:! or a 1:4 or whatever your trying to do.

I used .20 pitch everything good prices on these. I use kevlar reinforced where I can least stretch and happens in the first period of its life. I use a 14tooth drive pulley on my stepper and a 48tooth on a shaft down to a 14 tooth to get more speed this comes from a David Solsylva solution.

Coog

[mxtras]

Check here:

http://www.sdp-si.com/

It's a good starting point.

Scott

[mjs79]

so by the sounds of it im best to buy 2 new pullies and know they mate ,plus a kevlar belt .ill check out that site and place an order thanks ^^^^^^^

[mjs79]

one last question if i may , looking at the above listed web site . i found pullies that will work out for what i need . now im lost on the belt lenght . is the length the total circumference of the belt . or the circumference divided by 2 . am i even close
thanks again for your time and effort .

mike

[bearwen]

mjs79,
I believe the belt length is the total circumference but on the sdp-si website there is a link on the left to technical info its in there somewhere I read it but dont remember but I am pretty sure its total circumference.
Bearwen

[bearwen]

Coogrrr,
I am curiouse you said you used .2 pitch for everything isnt that the XL belts if so what exactlly are you driving and what not I am currentlly designing a new machine and looking at belt drives no screws and trying to figure out the torque formulas and what belts can handle what loads etc.. very curiouse please let me know.

mjs79 didnt mean to steal your thread just saw coogrrr reply and had to ask.

Bearwen

[RICHARD ZASTROW]

mike, The length of the belt is it's circumference at the pitch line. This is usually about where the cord is buried in the rubber. This coincides with the pitch diameter of the sprockets. Unlike a gear, this is larger than the OD of the sprocket.

All the main manufacturers of synchronous toothed belts have web sites with all the engineering data for their stuff. This includes ratios and center distances for belt/sprocket combinations.

I just learned Gates now makes a carbon fiber GT2 belt. Supposedly the latest/greatest, least stretch, greatest power transmission etc. etc. etc.

Good Luck in your design.

[mxtras]

http://www.sdp-si.com/Cd/default.htm - center distance and belt length (# of grooves) calculator.

Scott

[mjs79]

thanks everyone for the help ill use the link above and see what i need . thanks alot
cheers
mike