i want to cut timing pulleys , so help !!

[RICHARD ZASTROW]

Don't forget shaping or broaching. A slotter attachment & rotary table/indexer would allow you to use a hand ground tool to produce a sprocket. Any slotter or shaper could be utilyzed. Without an indexing device, you could make a fixture to locate the sprocket center and undersized holes from skmetal7's idea to position radialy. The shaping/broaching could then be used to finish the contour. Just an idea.

[Zumba]

Seems counter productive to make your own timing pulleys. Lots of research went into designing the GT type belt/tooth shape to increase accuracy. I'd rather spend the couple bucks and buy the pulleys, even if my budget can only afford plastic.

Of course this only applies to small ones.

[derekj308]

Hi Guys

This seems to be semi relevant to this post so here goes

http://www.cnczone.com/forums/showth...t=24688&page=2

Posts 16 and 18

Two ways you can go.

1. Grind your own cutter based on 'ideal' profile and ......
2. Mill the ideal profile by splitting the pulley in half and ......

For the 36 tooth pulley I posted the minimum radius is R1.25 so you can use a 2.5mm dia cutter. The profile is as per Gates design, straight off their website.

Cheers

[Pressfit]

Originally Posted by skmetal7 can u make something like this? all it is, is a 2" (or whatever size u need) dia. piece of aluminum, a hub turned, with a groove to align the belt. holes are drilled in the side to make the timing teeth. all u would need is a lathe to turn it to the size u need and a mill/rotary table to drill the holes.

Iv'e cut this type of profile before on our Fellows gear shaper but it was so long ago I had to think a while. I seems to most closely approximate this profile.

[in2steam]

Originally Posted by RICHARD ZASTROW skmetal7, That would work IF you can find a belt that has a round tooth contour and you put the round holes on the correct pitch diameter and pitch that matched the tooth spacing of the belt. However, all the readily available belts that I'm aware of are of propietary shaped teeth and they are not round. They are compound blended angles with blended radii designed to mimic the involute gear teeth. Unless the application of your pulley is slow speed and limited use, the pulley (sprocket) would eat the belt alive. Snoop around a bit, there may be a belt available that fits your idea. BTW, I live near you, Hartland, WI

Richard alot of automotive "timing" belts are starting to use round tooth contour, I cannot garauntee that is perfect radi, but when I was still working at a local(to you to also) ford dealer now owned by a one time govenor canidate, they were just starting to come out on the newer vehicles. I was told by a completly unreilable but none less inteligent source that they provided better preformance at higher rpm of modern engines with some gripping sacrafice. Thats not that big of a deal as they tension them in many ways sometimes more then once.

max-imum_2000 if its not a round tooth then I would be shaping, seems like the most logical approach short of horz. miller with the right contour cutter esp if more then one is needed. Either way if its a stock belt I would just order the thing someone must have the right sizes.

Chris (in grafton,WI)go badgers!

[RICHARD ZASTROW]

Personally, I would buy/modify an existing sprocket. However, max-imum2000 is located in Egypt and stated he wants to make his own sprockets for his own reasons. I am just making suggestions and giving cautions to help do that. Obviously I am not the only or last word on the methods etc. As to the round teeth, the new belts are far superior to belt construction and materials of only a few years ago. I do not believe the new construction is available in the old style belts. Could be wrong though.

[BobOD]

I'm flat out amazed that a milling cutter for this is not readily available and easy to find???

Buy and modify...not always possible, certainly not fast enough for quick prototyping.