2x72 clone questions, tracking, and bolts

[Dixieblade57]

I have been working on my 2x72 KMG clone. I have studied the original as well as the 100's of copies and variations of the original design, and while mine is similar to the original I like others have made a few modifications. In regards to the original a couple of questions are popping up in my mind!

Concerning the tracking mechanism there are very few video clips that show the off side or what could be said to be the left side of the machine. Most clips that show that side are just very brief shots. Most show the machine from the right side or the pulley side.

Ok here is my question on the few clips of the off side of the machine I have seen. I do not see an adjustment knob for the tracking mechanism on the tension/tracking Arm!
There has to be one, isn't there?
Other wise how would they achive tracking?

Also in regards to the tracking mechanism. I assume that they are using a bushing or sleeve to keep the distance from the face of the tracking pivot to backside of the tracking pulley the correct distance. I have plans to buy my pulleys from Rob at Beaumont and really need to understand the bushing thing and the length of the bolts required for those pulleys before I go any futher and screw something up!!!! No where in Rob's list of parts do I see a listing for what I suspect must be those bushings to space the wheels, so I need to know the length and for sure that is how they achive the proper spacing!
Does the bushing run against a bearing in that pulley (if not how come it doesn't wear out the back side of the pulley)?
This bushing thing would apply for the contact wheel as well, is that correct?
If not please explain how that distance is maintained on the tracking pulley and contact wheel to match the drive wheel?

I have another question in the videos I see the guy changing belts and never having to readjust the tracking. I have used several belt sanders and no matter what the belt has to be adjusted with each belt!
I think it has to do with how the belt stretches if its a used belt but even when you slap a new one, adjustment is one of the first things I usually have to do to get the tracking right!
How do they not have to readjust each time or are they just omitting that step in the videos?

My next question is concerning the bolts used for the tracking and for the work arm. I want to purchase 1/2" grade 8 bolts. I would like to go ahead and buy the bolts but don't want to end up getting the length to short.
Does anyone know the length of each perceptively, the tracking bolt and the bolt used for the work arm?

Thanks in advance to anyone who can shed some light on these questions!

 

[rfrink]

I'l take a shot at a few of these questions:

Yes, there's a tracking knob on the KMG. It's a knurled screw (1/4-20) on the tension arm that tips the tracking wheel up or down which steers the belt side to side.

The mechanism was copied from a vintage Powermatic bandsaw.

You need a way to precisely move the wheel by either tipping it up and down, or steering it left to right (Bader) or moving it in or out of the plane of the belt line. Once you achieve a precise way to move the wheel in a repeatable manner...then the sensitivity of the tracking adjuster can be refined to get the "feel" that you want. You can use different thread pitches on your adjuster screw or change the diameter of the tracking wheel itself. If it's too fine, it will become a pain in the neck...too coarse and it will tough to accurately position the belt. Based on the 1/4-20 screw, over the first few years of the KMG...the tracking wheel diameter settled on 3-1/2" diameter. This seemed to provide the best "feel".

The bushings/spacers are 1/2" hex nuts. They are also used a jamb nuts to keep bolts from unscrewing. The contact wheel gets a special custom made nut ( .980" long) to provide the correct spacing. You'll want the centerline of all the wheels to be in the same plane....or at least within 1/8" or so. It's not terribly critcal.

You really don't need to re-adjust each belt very much...or, at least, I don't. I just put it on and let it fly. It's really very simple and only takes quick twist on the tracking knob if you do. Maybe a really do adjust it...but never even think about it..and don't realize it. Regardless...it's not an issue.

The bolts on the KMG are 1/2-13 X 3" GD5 HHCS.

Have fun with your project.

-Rob

 

[Dixieblade57]

Hey Rob thank you very much. There are not many out there that would offer up the information so readily!
I do appreciate all the info and have sent the comapny a private email concerning the items I need to purchase. I have always heard you were great to work with and this proves it!:thumbup::thumbup: