Belt Drive Conversion for Grizzly G0704

This mod precludes the use of the quill, correct? I actually prefer using the quill rather than the Z axis when I can. It's frustrating to me how non-knee mills want to dive downward and I pretty much have to run with the Z axis locked. I'd really like to get the extra RPMs out of a belt drive conversion, though.
 
This mod precludes the use of the quill, correct? I actually prefer using the quill rather than the Z axis when I can. It's frustrating to me how non-knee mills want to dive downward and I pretty much have to run with the Z axis locked. I'd really like to get the extra RPMs out of a belt drive conversion, though.

This mod allows full travel and use of the quill. As soon as I get the tach pickup mounted, I'll let you know what the RPM is. My shop isn't heated and it just started getting cold here, so my shop time will a little more limited. I suppose an industrious person could calculate the rpm based on the original gear train ratio compared to the new belt ratio - I used a 25 tooth motor pulley with a 36 tooth spindle pulley. I had seen one on the net done with two 32 tooth pulleys but that one indicated that the bearings would not take the extra RPM, so I opted to gear it down a little.

Dan
 
Ive tore mine apart .
Took my spindle out stared at it scratch my head put it all back together... I have a very pretty Nordictrak 3.5hp/Kbmm 125 board & motor here waiting to go on it but just cant figure out how to mount the pulley and keep my quill.
I like using it for setting my Z height and power tapping.
If you would be so great to me and explain how to add a pulley to the set up and keep you quill I would be grateful.
Thanks
Mark
 
First of all, have you looked at the photos? Look them over and read this a couple times and maybe it will be a little more clear. If you look at the spindle while it is installed, you will note that there is a small amount above the snap ring at the top of the bearing. The tach pickup ring is mounted to this with two small screws. Take the tach ring off. What I have done is turn a recess in the flat side of the aluminum pulley just large enough to fit snuggly over the small amount of spindle sticking up past the snap ring. It should bottom out on the spindle and not against the snap ring. I then drilled two holes to line up with the holes that originally mounted the tach pickup, and bored the rest of the pulley to the same diameter as the inside diameter of the spindle, to allow the drawbar and everything to pass through it. I then bought screws long enough to go through the pulley and the pickup ring and thread into the two holes in the spindle that originally held the pickup ring in place. Now in my ideal world, I would like to drill two or 4 more holes int the spindle to make a total of 4 or 6 screws holding the pulley on, but I don't feel confident doing that just yet, so I'm leaving it at 2 screws for now. I used socket head cap screws - make sure you use good ones. I'm hoping that the recess will help support the side stress of the belt and leave the screws to hold the pulley in place with more of a clamping action with less shear force on them. I used a couple spacers to move the pickup ring u in line with the new location (just finished that today!). Here are a few more photos. With a 25 tooth motor pulley and a 36 tooth spindle pulley, I'm getting about 2600 RP forward speed.

DSCF1930.JPG DSCF1931.JPG DSCF1932.JPG DSCF1933.JPG DSCF1934.JPG DSCF1935.JPG DSCF1936.JPG
 
Thanks for the explanation.
It really helped me . I going to give mounting mine a try
~Mark
 
I'm thinking of doing this to my g0704. My plastic gear just bit the dust.

How do you figure which belt you need? And how long it needs to be.

I see you used the 25 and 36 tooth pulleys so I will go with them.

Ron
 
HA-
My nylon gear just stripped as well! Im taking this on along with ac bearing switch out.
Thanks for the info this is a great jumping off point!

:thumbsup::thumbsup:
 
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