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Posted: Sun Apr 17, 2011 2:29 pm
by JPG
crokseti wrote:Well I got the coupling package from Shopsmith so problem solved right?
Wrong!!! The accessories hub has 4 spline grooves but the plastic coupling shaft has 5 splines on that end.
So back to the pulley drive...
Anyone know the rpm's of the mark V drive motor?
I can figure out the nessessary speed by sizing the pulley ratios
On with the show...
I assume you purchased
this
Read the second and third sentence.
You need one of
these
The coupling kit includes the coupler and a hub for the HEADSTOCK shafts.
The spt hub comes with each spt when new.(not much help when purchasing 'used' and it ain't there.
If SS is 'out of stock', PM me and I will send you one to get you going.
Now about them pulleys etc.
The motor shaft is essentially inaccessible, and does not have a flatted shaft end for attaching anything anyway.
The idler shaft runs 1.6x the upper shaft speed. Thus the pulley ratio needs to compensate for that(larger pulley on the bandsaw shaft). A 3:2 ratio would be close(1.5)
Fortunately the bandsaw shaft is quite long.
You will have to size the belt very closely, but tension could be adjusted by raising/lowering the bandsaw in the spt mount(short distance!!!). You would want the belt to barely slip onto the pulleys, and then the bandsaw could be slightly raised to allow the belt to seat into the pulleys.
The bandsaw does not require much torque so minimal belt tension is needed.
With a 2" and 3" pulley, a 18" belt would probably work. A 4" and 6" would require about a 26" belt.
Posted: Sun Apr 17, 2011 4:17 pm
by dusty
crokseti wrote:Well I got the coupling package from Shopsmith so problem solved right?
Wrong!!! The accessories hub has 4 spline grooves but the plastic coupling shaft has 5 splines on that end.
So back to the pulley drive...
Anyone know the rpm's of the mark V drive motor?
I can figure out the nessessary speed by sizing the pulley ratios
On with the show...
The motor rpm is most likely written on the motor label and it is 3450rpm and the bandsaw should be operated somewhere between 700rpm and 1050rpm.
Posted: Sun Apr 17, 2011 11:01 pm
by crokseti
I've ordered the correct hub and used duck tape to temporarily, run the saw.
I had to cut out some blanks to keep the operation going.
Tomorrow I'm clamping a short section of garden hose to get more torque
so I can process some thicker pieces.
After cleaning, lubricating, and adjusting, the power plant is working smoothly.
I did throw the rubber belt on the bandsaw pulley and will have to replace yet another part.
Here's our website for displaying and advertising our products.
rockytopcarvers.com
Thanks everyone for your input. I learn more about this machine everyday.
Posted: Sat Jun 18, 2011 2:32 am
by seajayf
I stumbled onto this thread while trying to figure out what I just bought. It is a 1980 MV but the top accessory hub has been modified to a pulley with a series of belts that go to pulley mounted below and then back up to pulley on the bandsaw where the power hub should be. Any thoughts about what is going on here? The original owner has passed. Thanks, CJ
Posted: Sat Jun 18, 2011 6:01 am
by peterm
Does your setup look like this?:
[ATTACH]13409[/ATTACH]
If so, the article explains.............
Posted: Sat Jun 18, 2011 10:23 am
by seajayf
prmindartmouth wrote:Does your setup look like this?:
[ATTACH]13409[/ATTACH]
If so, the article explains.............
Yep, that appears to be it. Hmmm, what to do with it?
Posted: Mon Jun 20, 2011 4:27 am
by paulmcohen
This picture while called a speed reducer does not change the speed. For it to be a speed reducer you would need for the pulley sizes to be different. 2/7 * 7/2 = 1. What am I missing?
Posted: Mon Jun 20, 2011 6:16 am
by peterm
The lower shaft turns at 2/7 the speed of the SS spindle. Then the 2/7 to the bandsaw reduces once again.
Posted: Mon Jun 20, 2011 8:23 am
by dusty
paulmcohen wrote:This picture while called a speed reducer does not change the speed. For it to be a speed reducer you would need for the pulley sizes to be different. 2/7 * 7/2 = 1. What am I missing?
Paul, this is not a math problem; it is a series of pulleys and belts.
For every 3 1/2 rotations of the drive shaft the first large pulley will rotate 1 time (a 7:2 reduction). Now, since the first large pulley and the second small pulley are on the same shaft, they turn on a 1:1 ratio. The second small pulley must turn 3 1/2 times to cause the second large pulley to rotate 1 time (another 7:2 reduction). Thus, this arrangement produces a 14:2 reduction in rotational speed.
Posted: Mon Jun 20, 2011 10:19 am
by damagi