Well, most of it machined now. All machining ops in the lathe done except for chamfering and parting. Looking nice apart from the inside of the thin wall where vibration marks have set in.
I have been taking pics of it as it goes. Will put them online when I have the job complete.
I have made the thin wall 7.5 mm deep and a step of just 0.5mm. The step is really only a clearance step anyway. (however, I will double check in the morning...
Thanks for the help, advice and drawings. :-) (Oh, I did note on the drawing, the inner diameter of the spigot. I had to go back to my drawings to double check the dia.)
(the last 2 are the photos using the lens at each end of its zoom)
Had a few probs that I had to iron out, but I suppose that is the prototyping.
I had to skim more of the inside of the thin wall, then turn more off the hieght of the thick piece (after filing the spigot lower due to it interfering with the inner barrel.)
I also had to trim the inside of the zoom barrel to fit the piece into.
The screws, I couldn't get hold of an M1.6 tap so used 10BA instead. Screws fit quite tight and well. (see pic 19)
A number of times, the damn thing kept moving when I kept having to trim extra bits off it. I thought I was going to have to make the whole thing over again a number of times. Luckly though, it didn't bend.
The only problem I have now (2 probs). 1. I didn't glue the ring in place. Mainly due to the really tight gap, but I thought then that there is enough friction to keep the ring in place. However, I can adjust the ring position.
The barrel is way to tight to turn naturally. I think the height of the ring is still too much and the cover (cover with orange ring on, photo 20) is tightening down onto my aluminium ring and effectively locking it. (I can move it, but it is really tight.)
Still having to mod it... (done now). I had to shave some off the height to fit the cover with the orange band on. I then forgot about the chamfer. The lens became really tight to turn when that cover was screwed down. This morning, I discovered that the cover actually has a machined / moulded chamfer, so I had to strip the lens again to chamfer the ali ring. It is MUCH better now. Still a little tight, but nowhere near like it was before.
No, that is actually from the original piece. The spigot on my piece is effectively the black broken piece in photo 1. That has a small steel 'arm' that is screwed to the spigot. Is that what you mean by a packing piece?
All I made for it was the aluminium ring. (I had to make some clamps (basically just a lump of metal with a hole drilled in) in order to fasten my lathe chuck to the rotary table)
If you look at photo 19, the inner ring where the actual lens is, you can see a slot. That piece where the screws are rides into that slot, so when the ring rotates, it drives the slot round which has a (VERY) course thread to drive the lens forward (downward in this photo) to zoom..
The two screws were like that when I took the lens apart. Because of the head size, I had to measure both screws just incase they were different threads. They are both the same thread, just different sized heads. (I thought it was odd as well.)
I quite pleased with it. I only bought the rotary table a few weeks ago. That has just paid for itself. The only real cost was my time. (At my hourly rate as a computer programmer, I could have bought two lenses, but what I thought to myself is why waste a perfectly good piece of equipment due to the failure of something I could very easily manufacture to fix it.) It is just a shame that the cost to have something fixed by the manufacturer is almost the same as the cost to buy a new item, which makes such things now just throw away.
That - complete with dividing plates - was one of the first things I bought after the lathe itself. Wanting to cut gears I thought I couldn't do without one.
Don't ever consider your time !! It is always a shock to realize what the part has really cost you :))
I needed an M3 x 4 grub screw yesterday and by the time I'd made a fixture to hold a cap-screw, cut off 4mm and saw a slot in it I'd spent nearly an hour (being in IT support I would be on similar remuneration to yourself )
I don't see any way out of that mentality for the vast majority of the population who no longer have the opportunity to get into manufacturing in this country :(
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