On Sunday 16 October 2016 03:26:55 Roland Jollivet wrote:
> Hi Gene
> Did you try this one <http://www.bbman.com/belt-length-calculator/> ?
> It's a bit confusing though, on the order of parameters to select.
> Just click about...
I played with that one the most, because it did look promising. But after
choosing the belt style, xl, and the tooth counts of the pulleys, it
seemed to freeze up and while the c-c length could be entered, nothing
came out except the pitch diameters of the pulleys. No clue if its
disabled over the weekend (I've encountered that before) or what. Ahh,
made it work, I had to click on the right hand panel. And the update
time lag is done so silently you have to sit & stare at the numbers to
see if they change. And they have a Kevlar version of the 160xl037 at
less than a fiver a copy. Thats a good price for a Kevlar backing.
I'll see if I can get the Z motor mounted & measured by tomorrow and get
a pair of both from them. And it looks as if they have them in 2 tooth
increments. But that one is glass reinforcement only at $4.17 in onsies.
Change of topic:
This screw, a 2505, has only a 10mm stud to drive it with, and its a bit
short, forcing me to put the pulley on such that the set screws are
behind. With the pulley turned around, its hub is long enough the set
screws are off the end of the shaft. The stub has no flats, so if the
screws damage the shaft, the pulley will be locked on. Fugly thought
When I did TLM, I was working with a handfull of the metal change gears,
so I sacrificed two of them by boring a taper for a miniature browning
style taperlock hub I made on TLM, in a 40 tooth I put on the motor, and
an 80 tooth I put on the screw. Used 8-32 drawbolts. That has Just
Worked(TM), zero slippage even when its accidentally pushing the locked
down (I thought) tailstock to the right on the ways. :)
I can make more of those hubs, out of steel rod. The question is, since
alu will cold flow under the pressure of the terminal screw when used as
an electrical conductor, will it cold flow and release the grip on the
shaft if I do that in an aluminum hub? I would turn the pulley around if
I did that since that would put the radius of the pulley over the
squeeze and put the belt tension directly over this stub. The extended
hub would serve for the draw screws to pull against.
When I did TLM. I hacksawed the split, but I can EDM those slits like I
did to grab the end of the x screw because it leaves no burrs, and
having 6 metal petals to evenly apply the squeeze as opposed to
forceably deforming the single slit flange sure seems like the better
way to do it. The only thing I'd worry about is will that bulk cross
section of the pulley cold flow and release the grip before I lose mine?
Theres plenty of bulk in that pulley since its a 40 tooth, nominally
2.5" in diameter, it sure seems like it ought to work.
Secondary question is, since this is dissimilar metals, what lube would
be recommended on the taper so that I can move the screws to the
threaded holes in the flange and jack it back apart again without the
screws acting like drill bits in that much softer aluminum. Milk of
Magnesia, or some sort of never-seize? One could also interpose a
suitable steel "fender" washer, drilled for draw bolt clearance, for the
screw tips to push against. I can do that, so the lubricant is the $64
question I guess. Recommendations?
[snip the rest of weekly paper]
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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