Taper Attachment in Latest HSM - spring tension

[J Tiers]

It occurs to me that 3 rollers may be a less desirable design than 4. While 3 are not kinematically redundant, and 4 are, 3 really only work well with the force against the 2. That can be made to be the commonly used direction, of course.

but if the single roller ever has to do the pushing, it will be unstable. There is always some slop in the system, and if any exists, the single roller might allow the "traveler" piece to twist to the right or the left, depending on direction of forces at a given moment, and thus cause a slight variation in position of the crosslide. Not much perhaps, but with tapers it may still be enough to make a difference.

I believe the factory-made units I have seen pics of have all had 4 rollers.

I like the unit in the pics, just wondering if it might be even better with 4 rollers.

[CCWKen]

I couldn't get the holes drilled and tapped in proper alignment for four bearings at the time. The one shown with three bearings was the third version. The cutting force is applied to the two rear bearings as they follow the guide. The front bearing has about .005" clearance to the guide but it doesn't even need to be a bearing. I could have just used an adjustable plastic guide/gib there. Eh, you learn as you go. I started with an idea and scraps on hand--No drawings. If I were to do it again, I'd have a better plan.

EDIT:
Another change I'd make would be to NOT make the angle sweep so large. The part toward the lathe bed can get in the way. It doesn't need to be so wide for most common tapers. Especially when using a 12" guide bar as I have.

[J Tiers]

Most such systems use eccentric bolts so that there is a range of adjustment on at least 2 and all 4 can be set to be evenly aligned. For instance, my radial arm saw carriage.