Re: Servo drives- exploding head - Router/plasma

> >For timing belts, it appears the GT2 is preferred and a 28 tooth gear
> >is the smallest for a 1/2 shaft.
> >
> >
> Preferred, but not if you are squeezing pennies, good quality xl

belting

> and pulleys work fine, as long as you purchase underbore, and have them
> bored and reamed to finish size, as most mfrs. feel that several

thou of

> runout is acceptable. Of note is that many, many machines have been
> built and running for years with xl or l series belts that are still
> making money today.

There are examples of almost everything. I think XL belts and pulleys
are great, easy to use, common, lots of suppliers, most sizes are
readily available.

As I understand the timing belts have a rating of 125 pounds per 1/8
inch width. I've seen that as 50 pounds, but not higher than 125.

XL is 3/8 wide, L is 1/2 so is about 33% stonger, but also much larger
and more expensive.

GT2 is 15mm or 0.59" so is 35% wider than XL but does cost about 30% more.

A 28 drive, 60 driven and 100 tooth belt from SDP cost

$41.70 for the XL (3/8 belt)
$54.20 for the GT2 belt (0.59" wide belt
$56.55 for 1/2" wide L belt

The L is much larger so would need a 15 drive and 32 driven to get
close, but 32 is the largest size listed for pulleys from them.

The L belt is 33% stronger based on belt width and 35% more expensive.
The GT2 is 57% stronger and 35% more expensive.

Interestingly the belt is the biggest expense for the GT2 stuff. The
pulleys are $2.00 more than XL.

For a unit with three axes, it would be about $37 ($13.55 each) more
than for XL, but with greater power ratings.

I can't guarantee my percentages are correct, but the cost difference
between belts favors the GT2 for the best bang for the buck, IF you
need the higher power.


Dave