Gear Cutting for a begginner?

[chich2]

I have finished the small pulley. As per chart information, an 18 tooth puley is almost the smallest I can go for the "H" series belt and still achieve a reasonable life from the belt and pulleys. Once I drilled and tapped the holes in the arbor I bolted the pulley blank to it then dialed it up in the mill. Since my dividing head is 40:1 I went 2 full revolutions and 4 holes on an 18 hole sector plate. (2 4/18). Here are some more pictures.

Chich

[fkaCarel]

Here a funny one. It started like this: I have a machine which uses 1" wide XL belts. These are special cuts, thus expensive and they did'nt last that long. So at the end I replaced it with two 3/8" belts XL side by side. Never had to replace them, so there must be also an quality difference.

Knowing this, and noticing in the catalog that MXL belts have the same diameter/width power transfer, you could make a reasonable power transmission in a limited space with more tooth on the pulley. As an MXL has the same pressure angle as an module gear, I could even use a gear cutter for these.

On the photo a 4-belt, one belt removed, in the background a hobbed timing belt bar, which are available at timing belt suppliers. But I see hobbing for timing belts not as necessary as it is for gears. With this approach and a casino like program to play with belt lengths and number of tooth I am able to replace gears. And this does'nt off course apply to automotive gearboxes.

[diarmaid]

Would the SIEG Super X3 mill be rigid enough for cutting gears?

I suppose it depends on the size and thickness of the gears your cutting.....?

http://www.syil.cn/

[Geof]

Originally Posted by fkaCarel Here a funny one. It started like this: I have a machine which uses 1" wide XL belts. These are special cuts, thus expensive and they did'nt last that long. So at the end I replaced it with two 3/8" belts XL side by side. Never had to replace them, so there must be also an quality difference......

Did you monitor operating temperatures? Two narrow belts would probably run at a lower temperature than one wide; the surface to volume ratio thing in action once more.

[fkaCarel]

Bit difficult to monitor the temperatures, with a damaged original one. It's just typical that a replacement with a reduced width of 25% last longer, as in till today. A two belt replacement, directly available, costs up and about 3 Euro, instead of the original +/- 15 Euro, so I am more careless too. The pair is 12 years old now, while an original lasted 5.
As a timing belt has a spiral cord it tends to move to one side according to direction, so they are cosy side by side, closing the extra cooling area. The sidewall of an XL belt in only 1mm, so there is only a slight increase in cooling area.
I know there are quality issues with timing belts. I read here that Uniroyal invented the timing belt in 1946. At a certain moment production was licensed, patents freed, with quality issues as a logic consequence.
But honour to honour, these are Pirelli's.

[FPV_GTp]

nice work guys