On Wednesday 21 September 2016 01:15:54 Chris Albertson wrote:
> Actually drilling the timing belt is not a bad idea. The older MXL
> type belts used a trapezoid tooth belt but the new high torque "HTD"
> Designs use circular profile teeth. They really are bater and
> transmit more torque with less belt tension required. Even newer
> designs are GT2 and GT3 and they use circular test also. It seems
> counter intuitive at first that round teeth would hold more force.
> But the load is more distributed the the tooth profile lack street
> concentrators (corners) Any new design should be using g the HTD or
> newer profiles
> This is the tooth design I was thinking of when I said "ball end"
> While on the subject I found a neat program that will let you design
> almost any kind of gear (yes ANY kind, even non-round ones) then then
> it creates G-code to make it.
> I've not used it myself and likely will not as it seem to run only in
> MS Windows.
And on checking, the license is $120 USD. You can dl either version for
free, but I'd expect without the license, it can't save or generate the
gcode. It didn't say whats disabled in what I read, so thats a swag.
Given the usage I might use it for, I think I'll pass. I have a alu bar
headed this way to make that special hub I need from, and I have the
gear I'll bore to a pressfit on this hub, on hand allready. After the x
is running, next is little connectors to couple the ends of the bellows
type screw covers for the z screw. Probably with 4 different treatments
to the flange. Its hanging there now with paper towels draped over it.
> On Tue, Sep 20, 2016 at 2:20 PM, Martin Dobbins <tu...@hotmail.com>
> > Gene wrote:
> > >The ball end wouldn't be the tool for the job as the bottom of the
> > > gullet
> > has sharp corners except for the OEM belt of a 7x12. And there >are
> > 2 common face angles in >use and I've not the memory to quote
> > whether its 14.5 degrees or 20 degrees for the face angle per belt
> > tooth style.
> > >Bigger than xl is probaqbly 20 degrees but that leads to belt
> > > hopping if
> > not tighter than a drum so I'd assume its 14.5 on the xl as they
> > will rip the teeth off the backing >before they'll hop a tooth,
> > assuming the shaft centers can't flex.
> > Absolutely no experience with timing pulleys here :-), and of course
> > from that perspective it's always "how hard can it be?"
> > No cnc abuse in this video just a lot of old British iron, but where
> > do you get the tooth profiles from? "You can see the belt
> > manufactures details or get the profile for the cutter by curving
> > the belt to the required diameter.?" (from the comments below the
> > video)
> > https://www.youtube.com/watch?v=kCiujbcrQzc
> > This fellow just drilled some holes, but since he glibly points out
> > that in his case it was pure math to decide drill size and spacing,
> > it *must* be OK.
> > https://www.youtube.com/watch?v=vJaacHN-A0Y
> > I posted this without a thought to the serious matter at hand, and
> > just hope it brightens up your day.
> > Martin
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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