Looks as if you have a small vertical step at the bottom of the triangular guide on each side. A simple rectangular slot engaging on those vertical steps would probably give sufficient location when fixing a bed stop. Less than elegant tho'. The job would be neater if something fairly close to the triangular section above the vertical steps is cut by whatever means you have and the gap filled with metal loaded filler. Press the filled slot onto a well lubricated section of the bed to get the shape just so. Once its painted the filler won't show.
One advantage of the using filler to get the right shape on the triangular part is that a fairly rough job is actually better than a super smooth machine finish as giving plenty of nooks and crannies for the filler to grab. The good metal loaded fillers tend to be moderately expensive and come in pack far to large for a single small job. JB Weld is easier and cheaper to find and works well provided the layer isn't silly thick. Advisable to put dams of some sort in if using JB Weld as it can slump. I've used duct tape and plasticine for dams in the past. Worked well enough.
Johns drawings show a functional and good looking device.
The bedstop for my Smart & Brown 1024 has the clamp fixings on top of the stop rather than, as is more common, below. Two bolts with square heads same size as the ones on the Dickson tool fixing bolts so the spanner is always to hand. I find this a very convenient set-up.
Clive.
Edited By Clive Foster on 23/04/2018 15:33:54