[Arich0908]

I need to make a few timing gear pulleys.
Ide like to know how to make them well just because.
Ive looked on you tube and seen a few ways but its not making much sense.
Can some one explain to me how they do it manually .
I dont have a CNC so ...
Thanks for the help

[chich2]

Arich,
I have made a few manually. I used the horizontal arbor in my mill and a dividing head. First I made a cutter that holds a piece of tool steel. Mounted the blanks I made then stepped out the teeth with the dividing head.
There are pulley tables you can get off the net that tell you the blank diameters you need to machine to before cutting the teeth.

I made these for a supercharger on a truck but I personally think it's cheaper to buy small ones rather than make them your self. If you wish to make them for fun then I have added some pictures of how I made my big ones.

Hope this has been helpful,
Chich

[Arich0908]

chich2 ,
See I just dont under stand how I know how to cut the tool bit to fit the teeth in that application.

[simpson36]

Here is a configuration to use on a conventional vertical mill

[nomedia="http://www.youtube.com/watch?v=ViN4t4YI_T4"]YouTube- Gear or Pulley tooth cutting using form tool and 4th axis on Mini-Machining Center[/nomedia]

[Arich0908]

simpson36,
Thanks for the video.
I get all of that. I think I understand how to use the tool or gear hobb. I dont understand how to cut the tool bit . What shape size width anything of that nature.
I also havent found any formulas to make timing pulleys.

[knudsen]

What I do for gears is take the closest size same pitch gear and use that as a template to make the tool shaped like one valley. Blue and trace. Without a pulley to work off, perhaps you can work off the spec and test it with a belt. Or just buy one pulley to work off. I just use a 1/8" HSS in a holder I made like a fly but 90 deg.

[japroach]

http://www.cnczone.com/forums/showthread.php?t=14867

[meo_udon]

Uploaded with ImageShack.us

I'm use 3 axis milling to made it. I'm use XL belt.

[Arich0908]

knudsen;
Thanks That makes sense . The gear I want to make I have a belt to but not the gear.

japroach
Ive read that it not very helpful to the noob who has never made one or knows the ins and outs of making one.

meo_udon
Thats looks great.

What bout using gear hobbs? any one use those?

[chich2]

Arich,
It was a while ago now but I think I used the belt as a template to grind the tool to shape and size. If you google "timing pulley dimensions" or similar you will find all the dimensions of standard sized pulleys.
***Remember*** Pitch diameter is NOT the diameter of the pulley blank before you machine the teeth. Pitch diameter is the diameter of the chord inside the belt once it is bent around the pulley. Some pulley charts will give the actual pulley diameter.

Chich

[meo_udon]

I don't use any hob. I use 2.5MM drill for make tooths and mill circle later.

[Arich0908]

Thanks guys Im going to give some a go .I already have an arbor to hold a tool post vertical .
I bought allot of stuff at an estate sale and that was one of the tools. Ill stop back if I have more ?s
Anthony

[knudsen]

hobs are $$$. Usually less to just buy the gears.

[Arich0908]

I seen some vids on you tube and hobbs are real easy to make with 1/2 in drill rod.