Thread: Tinkerer looking for someone to do a little fab work.

Can you tell us what a SCAR Tagger is/does?

As you say nothing complicated but you'll pay an arm and a leg taking that to a commercial place, if they will even touch it (some don't like working for individuals as payment can be difficult to get)
A couple of points/questions -
Welding steel bolts to aluminium won't work - they need to be the same metal
If your internal diameter is 35mm, then your total diameter will be 41mm. Is that a standard tube size?
What is the adjustment on the LED mounting plate meant to do? Al tube is shiny inside so light is going to go everywhere anyway.
Are you supplying the materials or are you expecting the maker to do that?

Michael

Laser tag?

Thanks for the replies:

The SCAR Tagger is a prop 'gun' used in this sport: Laser tag - Wikipedia, the free encyclopedia
The part in question is the emitter on the front used to simulate shots from the tagger to whatever you are shooting at.

I figured that the welding between the steel bolt and the aluminium plate wouldn't work, but I was ever hopeful for an easy fix. I will go back and do a little re-design to put tension back through the bolt.

The diameter of the aluminium tube for the casing is 35mm internal and 41mm external, 3mm wall thickness, there is a typo on the sheet, my bad. I have no idea whether it is a standard size, I can't seem to find information on the standard sizes for plate and tube aluminium. If someone has experience with this or can tell me where to look, that would be great. I am quite happy to re-design the part if I can make it from standard sizes.

The idea of the LED mounting plate being where it is (being able to move a little should adjustment be needed) is to have the LED at the focal length of the lens at the other end of the tube. This creates a IR beam the same width of the lens exiting the tube. Yes, there is some waste light, but this is the cheapest way to get that beam, as paying to have a perfect parabolic mirror made is just out of most player's league.

As to materials, I am happy to supply materials, if I know where to look and can get them at a reasonable if not cheap price. If whoever ends up helping me out has some offcuts that will do, then so much the better.

I will update the sheet and re-post the link before too much longer.

If you can redesign to use 40mm outside diameter tube with 3mm wall, that should be readily available at any supplier.

I looked at a piece of stuff lying around today in the workshop and it was 38mm OD with what looked to be (with dodgy calipers) a 3.5mm wall section. It depends on the OD of the lens, although the tube could be bored out if the lens was slightly larger than the ID. Capral (Tubes - Capral) do a OD40 3wt, but usually there is a 6m length involved.
Looking at the drawing I'd be tempted to make the back part out of a solid section of Al; tap the back for a piece of althread and mount the adjusting bolts as studs in the same way in the front (all with loctite). Relieve the sides to save weight. The only thing that has me worried are the screws that hold the case to the LED assembly. I don't like fine threads in Al like that as they can easily chew out. I guess they could be helicoiled if they did wear (depends on how often disassembly was likely)

Michael

Originally Posted by DamoclesDesigns

The diameter of the aluminium tube for the casing is 35mm internal and 41mm external, 3mm wall thickness, there is a typo on the sheet, my bad. I have no idea whether it is a standard size, I can't seem to find information on the standard sizes for plate and tube aluminium. If someone has experience with this or can tell me where to look, that would be great. I am quite happy to re-design the part if I can make it from standard sizes..

CHeck out the little green book on this page
Aluminium Extrusions, Suppliers - Security Windows & Doors - Capral

Originally Posted by Michael G

Capral (Tubes - Capral) do a OD40 3wt, but usually there is a 6m length involved.

I get the impression from this comment that Capral are the only game in town over there? You don't have any smaller independent suppliers?

Perhaps I should start buying bits and pieces and posting them to you guys over there if that's the case! My local keeps a large assortment of offcuts of pretty much everything, and if they don't have that 100mm long piece of whatever it is you want, they'll go and make one quite happily...

There are smaller guys in town but they won't always have the size you want on the shelf. The larger guys either won't sell to individuals or have a minimum order quantity. The part in question is less than 300mm long, so I'm not sure whether my preferred supplier would really want to get a length in if I ask. He has previously if I've wanted a couple of metres of stuff but 0.3 is getting a bit small. We probably only have 2 or 3 decent cut to length places in Adelaide who mostly do steel with a bit of SS & Al thrown in when asked.
The important thing at the moment is probably the lens. I don't know whether that is a fixed size or whether it's more a "this is what I'd like" size. Once there is a defined lens size then the rest of the job can be planned around that.

Michael

Thanks for the replies guys. The assembly has been re-designed a little in order to make it easier to produce with standard sizes.

The main Al tube is now 40mm with a 3mm wall, the lens is already in hand with most of the assembly being built around it (it should fit in the tube, but a very small amount of boring may be required).
The mounting threaded rod is M14 to be inserted into a tapped 19mm diameter 2.5mm wall Al tube. Both tubes are standard from Onesteel (the only supplier I knew about at the time).
The threaded rod sections are to be of the standard steel, M5 and M14, with the nuts the same standard.

I have re-designed the assembly with a single block to mount the assembly, in the hope that it will be easier to mill from an Al block or to get 3D printed.

I still need to find a standard for the case screws and a supplier for same. The diameter doesn't bother me that much, but as the block will have to be tapped to that diameter and the case screws may take some impact, ruggedness would be good.

New design diagrams: https://www.dropbox.com/s/7giin7l432...20Exploded.pdf

I like that a lot better - I'd go with M12 for the rod rather than M14 but in principle that's a less fiddly bit of design.
Have you found a maker yet?

Michael

Originally Posted by Michael G

I like that a lot better - I'd go with M12 for the rod rather than M14 but in principle that's a less fiddly bit of design.
Have you found a maker yet?

Michael

Yeah M14 is a bit of an odd ball size.

M14 is oddball, you are right, but fortunately it exists and isn't terribly rare. I chose the size because it should fit into a tapped internal thread on the 19mm outer diameter 3mm walled Al tube, which appears to be a standard size.

Actually, I will make a list what needs to be done now, as the design changes have probably confused a few people:
-Mill or otherwise produce the mounting block out of solid Aluminium or print it with a 3D ABS plastic printer.
-Mill or otherwise produce the LED mounting plate, or print it with a 3D ABS plastic printer.
-Bore/drill a 5mm hole down the centre of the M14 threaded rod
-Cut the 40mm Al tube for the case to length and cut slots/holes etc for mounting

I haven't found a maker yet, no.

However, I have had a man who runs a laser skirmish business based on using parts like this take a real interest, so whoever takes this up may actually get some farther paid commission work out of it.