Are there any general guidelines on when you do and dont use a precision shim when mounting a wheel to some vslot of a plate.
For me, the shims act as a spacer between any surface and the bearing. I use shims on all my bearing applications to transfer the compression load to the center race of the bearings. Without a shim, any compression applied to the bearing will be carried equally between the inner and outer races causing binding.
what about alum spacers. if i was mounting a wheel directly to some vslot. I would have the teenut, then an alum spacer.. or should i have a washer before the alum spacer?
Spacers alone aren't very stable on V-slot as they aren't wide enough to span the groove properly. Best practice is to set a Slot Washer first.
In that specific case you would want to bridge the gap of the slot. Openbuilds sells specific washers for this. The precision shim wont effectively bridge that gap.
Some aluminum spacers have the exact same ID and OD as the shim. If you dont need the extra space provided by the shim, then as long as the spacer sits on the bolt and centers properly on the inner race, you would be fine.
Yes and no and depends on the combination. I don't use them with 1/4" spacers as there is no need. The 1/4" spacers provide enough of a gap that there is sufficient space between the plate and the extrusion to have bolt heads running backwards through the back side of the plate. Not so with 6mm spacers so I have to add a shim if there are any conflicting bolt heads (and thus I rarely use 6mm spacers as I am too cheap to pay for all the additional shims). As for diameters, shims come in 8 and 10 mm sizes. Imperial sized spacers are 3/8" diameter and metric sized spacers are 10mm.
A visual reference guide I am starting to create, to make it easier to determine lengths required. still a work in progress.
I have posted an updated reference guide for mounting Full size V wheels to Vslot using spacers have a look here V-Wheels to V-Slot Mounting Options
