On Thursday, June 18, 2015 at 12:17:07 PM UTC-5, Carl Ijames wrote:
"stryped" wrote in message
...

On Thursday, June 18, 2015 at 11:28:01 AM UTC-5, Carl Ijames wrote:
"Jim Wilkins" wrote in message ...

"stryped" wrote in message
...
I have a spare 13 horse Honda engine laying around and a need for a
vibratory compactor. My thought was to use the engine to drive a shaft
attached to two pillow block bearings. The shaft would have a piece of
square tubing or something else welded to it to create the "off
balance" effect.

Yes I know I can rent one but I need it for several different things
and not all at the same time if that makes sense.

Any ideas on the proper way to build the out of balance shaft? Such as
how much weight and how far from the centerline of the axle it should
be?

Thanks,

============

You could rent one the first time and study its design.

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HarborFreight has a 6.5 hp model,
http://www.harborfreight.com/65-hp-p...tor-69738.html, they say
5500
beats per minute and a total weight of 176 lbs. In the manual is an
exploded diagram that is probably close to scale, which makes it look like
they step up the engine speed less than 2:1 with pulleys and two drive
belts
in parallel, and the eccentric is pretty small. They list the bearings
for
the shaft as a 6308 so that tells you the shaft size and what strength
bearings they felt it needed, the weight looks to be less than the shaft
diameter and tight to one side of the shaft. They claim 3000 lbs of
force.
Anyway, just one place to get some info.

-----
Regards,
Carl Ijames

Thanks so much. What size would you say those pulleys are?
================================================== ==================

No comment :-). If I had to guess, I would print out that page and grab
some calipers to get the ratio. Look up the 6308 bearing and use the
eccentric shaft diameter to get the scale factor, then you could estimate
the pulley diameters. If the motor runs at 3600 rpm which seems the popular
speed for governed lawn mowers and such, and they get 5500 beats per minute,
the step up ratio has to be 5500/3600=1.53 or just 1.5, and then just find
some pulleys to get that ratio. Read the rest of the manual to see if they
specify the engine speed, in case my 3600 guess is wrong. It's on sale for
$550, and you could probably sell it for over half that when you are finally
finished ... (Just saying; I know, building is the fun part for most here.
For me it's doing the design work, I think through lots more designs than I
ever try to build.)

-----
Regards,
Carl Ijames

Looks like a 6308 bearing is about a 1.5 inch shaft. I would have never guess it to being that big....