DIY Laser levelling using webcam and laser level

[devmonkey]

Quick question have you checked the end float of this trim router.? I've had quite a few of these trim routers and they are not the best-built things so I wouldn't be surprised if it didn't float more than the Um values your chasing.? . .Esp trying to mill steel with it.!

The frame doesn't look that large do you know anyone with a large surface plate could fit it on. If so then I'd suggest you use Metal Repair paste, like Belzona 1111. This is the method I use for machines that will fit on my surface plate. Better than Epoxy and about the same in costs. It can be Drilled and tapped easily and as strong if not stronger than the metal it's bonded onto. Isn't too fussy about temperatures and they even have types that can be used underwater or subzero temperatures. Dry's in hours not weeks.!

https://www.belzona.com/en/products/1000/1111.aspx

Yeh I checked it with a DTI, if there is end play it is less than 10um so hopefully it will be ok. The little router seems quite happy with steel, I only need to take off about 1/4mm. The best approach is to use masking tape to shim the router off the plate by the the thickness of the tape, cut the surface, then remove the tape and re cut, cutting loads on the 'finish' pass are almost nothing as only taking off a tiny amount of material. I've tested this on a bit of scrap flat bar and it leaves a flycut quality finish, shiny.

I did ask my mate who has a precision machining shop if he would be happy to surface mill the whole thing, he said he would but there is a long queue and since it is run like a clean room for doing some specialised parts I don't think he was overly keen me on me dragging in a great lump of dirty steel ! Good idea with taking an impression of a surface plate, I don't know anyone locally with one though other than him.

If I screw up this optical levelling I might go back to him, there will be enough material left for surfacing.

I've fixed the problem of my compressible work bench by removing one frame of reference, laser is now fixed to a lump of box tacked to the frame:


EDIT
That metal repair paste looks fantastic, it is epoxy based as well unlike the polyester rubbish I have here.