None. Both holders are in the small lens case in the parts box. Take care when cleaning out any lens fragments. Don’t lick your fingers!
Meanwhile, @frasco are you going to give your lathe method a go?
It’d be good if we could have something working by Saturday.
Of course.
Still waiting for the aluminium I ordered last Tuesday to arrive, but even if it does not come today, I’ll be in the space later to cut a mndrel.
What stock are you waiting for? I have some bits of material at home. ?
In theory the 20mm rod we have should suffice. I need to turn a good fit for the circular section of the holders which is about 19.8 and 19.4 for the two holders, but the diameter of the stock is about 19.9mm and has some drawing imperfections. The 25mm rod on order gives me plenty of margin for cutting a nice clean reference surface.
Before I model and print something incorrect, @tomnewsom can you confirm requirements.
Model the existing piece, make it fit both directions of insertion so lenses is centred, what apeture do we need for the lens?20mm?
Anything else?
Yeah 20mm for the lens. If you cap one end of the guides, then it’ll only go on one way (which is good). The Trotec ones are uncapped because that’s hard to machine in metal, I reckon. Don’t forget the alignment ring on the underside. The OD of that is engaged by the locking nut to properly centre the holder.
Trotec could fix that by putting a metal nub on the outside edge to stop it going in fully when you put it in the wrong way and also act as a holder arm.
The 3D printed part will only be for short term use. I was going to make it symmetrical so you slide it in all the way in either direction and engage the locking ring…
Possibly only the heat coming from the cutted material, hopefully none.
I don’t think the lens itself come hot, maybe just warm.
Is the precision of the 3d printer going to be enough?
shall we use the xyz ?
My suggestion would be that I bring the thermal camera in and we can take some measurements after a few minutes of cutting?
yes! but , like , in general 
Precision in the Z direction is not too important so long as it’s flat. The focal zone is quite long, so some 1/10ths of a mm there is not important. The centering is the important thing, to ensure the beam comes out perfectly vertically.
I’ve handled the cutting head during/after heavy cutting sessions and never felt any warmth.
Also as a quick aside, I’ve got the soldering iron thermometer if you want to calibrate the irons, one of them was 50ºC out from the displayed temprature.
The aluminium has arrived, so I’ll be in later!
We are currently locked out of the space.
Updates here:
https://discourse.southlondonmakerspace.org/t/important-space-closed-due-to-membership-system-problem/6362/2
…and some 3D printing was creating a test part later thanks to @Jonathan (tho’ I don’t have the photo to prove it).
@lasertechs the cutter seems to have been working well at the weekend thanks to @Jonathan (and possibly the efforts of others). And @frasco was working on an aluminium lens housing.
So…can the cutter be declared operational again?
Yes it can. Sorry I thought I told Jonathan to mark it In Order, but that was on a rather noisy phone line so the message might not have got through. I’ll edit the title of this thread 
@lasers - the laser cutter is back in action with a 3D-printed lens holder. Please be careful when removing it to clean the lens; it’s not as robust as the metal one. Also note that the lens is mounted upside down. This doesn’t affect cutting performance, but it does mean that you now need to clean the curved side of the lens.
Frank is currently working on re-boring one of the metal holders, which should hopefully be the long-term solution.
