Not bike frames, but related to some work on bike frames - I need to get an accurate rectangular frame with a sliding/adjustable upright set up. The upright will slide / move and clamp along one of the rectangle's sides and hold a laser pointer that can move up/down to take X/Y dimensions.
It doesn't need to be accurate in engineering terms, just stable, easy to adjust a mm or 2 'nudge' at a time and to stay in alignment in use. The sort of thing that could probably be made from Al section like this


with suitable corner pieces. Bolt-together would be ideal so it can be dismantled when not in use. I can cut the ends to an accurate right angle.

1) Anyone done similar and have any tips for bolted corner join pieces? Looks like these would do it


2) I've had a look around but not found a solution to make the upright slider work.

3) The upright and the section it 'slides' along would need a metal ruler fitting to it for consistent measurements, but only to the nearest 0.5mm. Not sure how to do that, had hoped to find a self-adhesive metal ruler strip. RS have a 1.2m steel rule .. at £479

If anyone knows of a good place to get something like this made to spec it'd be useful, thanks. Personal rather than company funded project so looking for modest costs rather than a full commission.

https://www.ebay.co.uk/itm/154865221453

This might work
Stainless Steel Miter Track Tape Measure Self Adhesive Woodworking Ruler


And threaded corner feet to level it would create space for 3D printed slider section that slides over the 40mm Al box section and uses a thread and nut in the channels to hold

Massively overkill, but have you looked at PVD http://www.peterverdone.com/ and the modular frame jigs he makes and uses?

Otherwise, you can definitely get screw in corners for use in large display boards (might be what you showed above)

I have, he's a number of levels above me in engineering smarts and fabrication ability.. 35th chamber level stuff on his blog. His new frame fixture and road bike work is something else.

Something like this should work for the sliding elements: https://store.boschrexroth.com/Assembly ... clcl=en_GB

There's a list of other bits you need to make it work under Technical Specs. Some kind of lever-operated clamp would be a good idea to allow for easy adjustment. They make other sizes too, so just pick the one that matches the extrusion size you're using.

I think you can bolt other profile sections directly to the carriage, as the hole pitches look like they match the rail dimensions.

As for the corners, the cast brackets work fine. You can also get longer ones for a stiffer connection. Bosch Rexroth don't seem to publish angular tolerances for the 90° angle, but I seem to recall that they're pretty good.

The stick-on tape scales are good too. I've got them on a fixture I've made and they perfectly adequate for mm-ish measuring.

The Bosch Rexroth stuff can be pricey, but there are manufacturers who make copies of the profile. I've used KJN Aluminium in Leicester for several projects - they make Bosch compatible parts as well as Item. Pick a profile manufacturer based on the accessories you need to make the system work.

RS component's stock lots of structural systems including their own RS Pro stuff. I've used it and it was plenty good enough for my needs.

https://uk.rs-online.com/web/c/engineer ... l-systems/

Thanks Chris, that's all good to know. Useful link for the sliding section. Hope all's well? Saw Chris Ny. in town the other day.

Thanks John. The pics in the OP were from RS actually, just wasn't sure if they were a good supplier for things like this.

That aluminium extrusion is great stuff, like grown ups meccano :D
It's generally referred to as "2020" (or 4040, etc depending on what dimension your using) and is popular for all sorts of things. I've used it to make a bed frame in my campervan and also a frame to hold the solar panel on the roof.
It's also used a lot for building 3d printers and other cnc type machines so sliding parts are quite common too. Search for "2020 linear bearing" and you should find something which works for you.

I used the same corner pieces in your image for some places and angle brackets (like these from Screwfix) in other places depending on whether you need the attachments on the inside of the corner or not.

Brilliant, thanks Touch. Does look like big meccano doesn't it : )

jameso wrote: ↑Thu Jul 04, 2024 3:24 pm https://www.ebay.co.uk/itm/154865221453

This might work
Stainless Steel Miter Track Tape Measure Self Adhesive Woodworking Ruler


And threaded corner feet to level it would create space for 3D printed slider section that slides over the 40mm Al box section and uses a thread and nut in the channels to hold

Hey James,

A bit late to the party, but some input at least from using that!

I've used similar adhesive tape on my spirit level so I can use my laser level to measure spot heights about the place. It could work well, depending on where you place the tape and alignment markers etc.



There's all kinds of 4040 alu extrusion accessories and parts you can get/replicate to pretty much build whatever jig you want, and like you say 3d print the bespoke bits you want.

Zippy wrote: ↑Fri Aug 02, 2024 12:05 pm

jameso wrote: ↑Thu Jul 04, 2024 3:24 pm https://www.ebay.co.uk/itm/154865221453

This might work
Stainless Steel Miter Track Tape Measure Self Adhesive Woodworking Ruler


And threaded corner feet to level it would create space for 3D printed slider section that slides over the 40mm Al box section and uses a thread and nut in the channels to hold

Hey James,

A bit late to the party, but some input at least from using that!

I've used similar adhesive tape on my spirit level so I can use my laser level to measure spot heights about the place. It could work well, depending on where you place the tape and alignment markers etc.



There's all kinds of 4040 alu extrusion accessories and parts you can get/replicate to pretty much build whatever jig you want, and like you say 3d print the bespoke bits you want.

This looks like some proper posh bothy improvements. Good work

Cheers Chris, that's good to see, good idea. I could use something like that for the patio work.. that I really should finish before building bike measuring jigs.