Hi all,
Looking for ideas...
My son didn't put my camera away properly, then my wife moved it and dropped
it. The lens has a small piece that has broken off...
http://www.revilloc.com/lens.jpg
The piece attaches to the zoom ring and drives the internal zoom mechanism
of the lens.
I have tried supergluing the piece back, but it just isn't strong enough. I
guess that I will have to send it away for repair, but if anyone has any
ideas first... it would be appreciated.
Not really... the markings of the zoom are in reference to the location of
this.
I have been giving this a lot of thought...
My wife is going to call the sony center (it is a sony alpha camera) and see
how much it costs to repair. If it is extorniate (the cost of an identical
replacement is about £150), then no harm in trying to repair it myself.
If I do repair it, the idea I have had is to shorten the length of the tube
probably about 5mm (accurately measured length), then turn up an alluminium
stepped tube which the step will sit on the inside of the tube you see
(there is actually a step on the plastic tube, which is what I would turn
away).
Anyone have any thoughts on this?
(That bit of black plastic with the metal bit attached should be where you
can see the grey section in the tube. It points to the center of the tube.)
lol...
Considered that. Not sure what our excess is. I think also our home
insurance has a sort of no claims discount as well. That might make it still
uneconomical.
Cheers.
Best regards,
Dave Colliver.
http://www.AshfieldFOCUS.com
~~
http://www.FOCUSPortals.com - Local franchises available
Look on ebay
Bet you could find, the same cam in perfect working order for less
that £150
What model is it ?
If it's older than 5 years ...digicams depreciate a lot ..
My cam, An Olympus 2050 was £350 about 4 or 5 years ago ...now I can
pick the same one up on ebay for less than twenty quid ..which I have
done ..I now have two extra...and mint examples ..for back-up ..£15
and £18 off ebay
And, you could put your old one up for spares and repairs on
ebay ...if you are pleased with it's replacement .
all the best.markj
Hi,
It is a sony alpha 100. They only came out 2 years ago. I bought it the day
it was launched in the UK.
New lenses are only slightly more than the repair costs. (My wife has
checked today.) So, no real loss if I screw the lens up.
It will be nice trying to do a repair and I think the idea I have for it
will actually make it a stronger lens (won't break like that so easily).
Apart from that, if I document what I am doing (how to take the lens apart,
machine the part, fit the lens back togethor), there could be quite a few
people interested in bringing back their own lenses with this same
breakage...
All I would need then is a CNC lathe to keep up with the demand.
Before you go to all that trouble (or enjoyment!) it might be worth trying
JB Weld epoxy.
It's something like black in colour.
Judging by previous comments there may well be enough spare space around the
repair to put a decent fillet of the epoxy for stiffness etc.
Might even be enough for a cover plate on the outside.
If it fails all you have lost is time.
Henry
I will have a look at that, thank you.
Best regards,
Dave Colliver.
http://www.AshfieldFOCUS.com
~~
http://www.FOCUSPortals.com - Local franchises available
Further to my last message re this problem...
I am going to machine a component. I have done a drawing...
http://www.revilloc.com/lens-drawing.jpg
(it is 1.5MB)
I have planned most of the machining operations, but have one problem.
Another issue I have is that I have to have a really thin wall on part of
the component. Slightly less than 0.4mm. This is the only clearance I
have...
The drawing is not quite correct, but almost all there...
The spigot you can see in the main diameter, is about the same height as the
3mm step in the side view. The bit I am missing is that the remaining inside
diameter around the spigot should be 62.2. This is my step 9, but not sure
how to do it.
I will be machining it from aluminium.
If you follow the steps...
1. Turn OD 66.26mm x 12mm
2. Turn OD Step to 64.61mm x 6mm
3. Drill / Bore through to 52.25mm dia. This will give me the material to
create the spigot.
4. Bore 63.85mm x 6mm.
5. Start part off (this will be the top side of the 3mm step.)
6. File 45 degree chamfer on the top edge. (not shown on drawing)
7. Finish part off.
8. Drill / Tap 2 holes. (The screws measure 1.6mm. Any ideas what they might
be? I am thinking possibly BA)
9... Not sure what to do here, in order to have a uniform diameter most of
the way around of 62.2mm but leaving the spigot of 10mm. What I am thinking
is maybe to use something in my dremel type device mounted in the lathe and
do this before step 5. The prob I have is that attempting to mount in my
mill, I am likely to damage the very thin step. Another prob I could
experience is that if I do the dremel thing, then when I come to part it
off, I will have the spigot that may cause the thing to tear itself apart on
the intermittent parting tool.
I have available to me...
4.5" lathe,
Eagle 25 Milling machine. (Chester)
Rotary Table
Dividing Head
Dremel type device
Bench drill
Bandsaw
Another issue I may have is mounting the blank to be turned without crushing
it whilst boring. Actually, that might not be such a prob. The prob I really
have is just the machining of the spigot.
Any ideas would be appreciated. I will be attempting to manufacture this
this weekend.
Thanks.
Best regards,
Dave Colliver.
http://www.AshfieldFOCUS.com
~~
http://www.FOCUSPortals.com - Local franchises available
Proops were selling taps in the M1.x sizes at a sensible price recently
(but alas not dies). The camera would have to be very old to contain BA
screws.
I find cousins good for small metric taps and dies
http://www.cousinsuk.com/catalog/6/1112/1312.aspx
Unfortunately the price of their dies seem to have increased
astronomically since I last bought one.
Alan
Yikes!
You can sometimes get M1.6 (which is the next common size down from M2)
taps and dies from people who sell more ordinary sizes of taps and dies
at the smallest end of the range - these can be a lot cheaper, eg RGD
does a carbon steel 1.6 mm die for £3.11.
http://www.rdgtools.co.uk/acatalog/METRIC_TAPS_AND_DIES.html
[ a set of three 1.6 mm taps from RDG is £6.99, same page -
- doesn't say whether they are carbon or HSS though, for very small taps
I'd only recommend HSS - small carbon taps are too brittle, especially
for hand use, and tend to break.
Small carbon dies are okay though, if they break, which is less likely
anyway, you don't have the problem of getting the broken tap out of the
workpiece you just spent half a day machining! ]
-- Peter Fairbrother
I could be struggling to get an M1.6 in time.
I have just cross referenced BA threads and it looks like 10BA is also very
close. Would it be a problem for me to use 10ba and threadlock? (Yes, I
know, the angles are different, but for the size of the screw and the amount
of force on the screw, it can't be that much of a problem can it?)
Thanks for your advice. :-)
I nearly suggested 10BA as a option in my previous posts. Taken as a
percentage the O/d is 6.25% larger which is substantial as far as screw
thread tolerance is concerned but the absolute gap between the crest of
the M1.6 screw and the crest of the 10BA 'nut' when centred is 0.05mm
which means that one side could have a gap as much as 0.1mm if it sits
to one side. Bearing in mind that the thread flanks on one side will
always be in contact the real 'gap' is actually quite large -
certainly much more than the space you have between your new ring and
its mating component!
I leave it to others on the group who are more familiar with threadlock
or locktite to determine if this would be 'a bridge too far'.
A comparison drawing is on my site as before.
JG
A bit late coming to this discussion and I an going to propose a radial
alturnative solution.
As you say, your drawing is incomplete and I have made some assumptions
about the missing detail but hope that I have interpreted your needs
correctly. I've done an accurate drawing and put it on my wb site as a
.PDF - see www.special-time.co.uk/drawings and select the only one
currently there.
I would not start by machining the finished size at all. I think it
would be better to prepare a billet at (say) 68mm dia. x 15mm long and
hold that in soft jaws to machine the internal dimentions.
Then I would machine a mandril at 63.85mm dia. with a suitable tapped
hole in the centre (say M6 or M8) and a clamping disc 65mm dia -
possibly with a 62.2mm reference spigot if there is enough depth to that
dia - and mount the part machined ring on that to finish the outside.
The issue of the 'tab' with the two holes could also be better served by
this method since you could mount the 68mm dia billet on you rotary
table (again with the aid of the 63.85mm mndril) and mill the 62.2mm dia
for 330° (with a 3mmØ slot drill) finishing the precise shape needed
with needle files. You could also drill and tap the two holes whilst
still mounted on the RT.
Another radical option with regard to this 'tab' would be to fabricate
it . . . . see the section drawing at the bottom of my drawing . . . .
This would allow you to finish machine the 62.2mm dia. but would require
other work in milling the slot and finding a means to fix the 'tab' in
place - probably a cyanoacrilate adhesive but maybe a 1mm pin as well.
I hope this has given you food for thought if not a complete solution.
JG
Hi,
Thanks for this (and the drawing)...
After I posted the message initially, I had thought that I can use the
rotary table with the chuck off my lathe fastened to it somehow. Then use a
small cutter to cut the material leaving the spigot.
I would prefer to have it all as one as that will be stronger. I did try
supergluing (cyanoacrilate) the plastic one in my original photo but the
lateral force that the spigot needs to apply forced it off again. The spigot
drives the zoom on the lens so there is a reasonable force there.
The spigot itself is level with the top of the ring rather than the bottom .
My thoughts were that this obviously makes the whole thing easier to machine
as I don't need to machine on the other side to the very thin wall section.
This means that I could practically almost finish turn the whole thing in
one go, then mount on the rotary table to machine the spigot, drill and tap,
then back in the lathe to part off. All without removing from the chuck, not
that perfect concentricity is actually required.
The only thing I do need that is not on the drawing is a chamfer to the
outside top of the ring. I don't think this is critical, just a stress
relief of some sort and to not interfere with the ring that has to sit over
this.
If I get it finished (and I will) and it works, I will take a photo of the
finished article and post it. It will certainly save me £114 for a repair of
my lens or £56 if they can't repair it. I could buy another compatible lens
for £99 or an original for £150, but then they will still have this
manufacturing defect/oversight. I think making the ring from ali rather than
plastic will be much better for the lens. Aside from that, I can easily
afford a new lens, but where is the fun in that? The remaining parts of this
lens are in full functioning order and it would be criminal to throw it away
over something that can be so easily (and cheaply) repaired.
From my original photo, where you can see the original break on the tube,
that will be turned away by 3mm. The thin wall of the piece I am making will
sit inside this tube and I will superglue it. I think with the amount of
surface contact area will be enough to drive the zoom ring.
That would be an ideal scenario but if you do not have a fitting you may
need to make one - even if it simply locates in the chuck recess and you
can then clamp the chuck body using standard clamps.
It is certainly the best option but does pose some problems -
specifically there is no 62.2mm reference diameter
With a wall thickness of 0.38mm you most definitely do need perfect
concentricity, and I would suggest that trying to hold it on the thin
wall section would cause you far too much grief.
The likelihood is that it is there to remove the need to undercut the
mating part so that there is no interference between them.
I've done some more drawings (still at wwwspecal-time.co.uk/drawings)
to take account of your further detail and also to show each stage of
maufacture as I would go about it. I assume that you have soft jaws for
your chuck and are familiar with the concept of a sacrificial mandril.
The very thin wall is the key problem here, that is why I propose that
you make this one of the last operations.
I recall doing something similar many years ago when I wanted to fit
very non-standard lenses (from plate cameras) to my Pentax SLR but that
also involved screwcutting thin walled items.
I'msure you have thought about it but just in case it has slipped passed
you, you _do_ intend to paint the inside of the finished item matt black
don't you?
JG
Hi,
I had a look around your site whilst I was there picking up the last PDF.
Looks like you craft some nice watch cases. I am currently working in
Matlock (Derbyshire) and just up the road from where I work, as I was
walking past, I noticed a workshop with some very nice wooden skeleton
clocks in fully working order. I have never seen anything like that before.
They were very nice and very unusual I thought.
The way I was thinking of machining it was to make the blank deep enough and
have all the machined part still sticking out from the jaws so that I don't
hold it on any of the machined surface. Hopefully, this will not present any
crushing problems.
Also, doing it this way, as I then have no need to remove it from the chuck,
I should not need a mandrel.
I don't have a fitting for my chuck on the rotary table. I was thinking of
just clamping it down then clocking the inside of the bore to get it
concentric.
The thin wall will be away from the chuck and as I don't really need to
machine the 'top' (from your drawing, the thicker wall is at the top, so the
top is the upper surface), the 62.2 can be machined all in one setting. This
means that I don't need to hold it on the thin wall at all.
To painting the item black... I can see a possibility why, but why would I
need to paint it? The location of this component will never even see light,
The outside will be surrounded by a non-rotating ring (this is part of the
rotating ring) and the inside, there is a good 3/4" before it can see any of
the actual lens tube. A problem would be is that the 0.38 wall is actually
only giving me 0.02mm clearance and painting this would be a problem. I
guess I could paint the upper thicker portion as if anything is exposed, it
will only be this part.
Seeing a wooden skeleton clock was the initial inspiration for me
getting into watch/clock-making and discussion on the alt.horology
newsgroup made the whole thing take on a life of its own!
If you looked at the detailed drawings you can see that I am familiar
with machining thin sections even in wood! The bezel ring recess leaves
a 'wall' at 0.25mm thick and the ring itself is 0.3mm thick. Stainless
Steel stem tubes are often 1.6mm dia with a 1.5mm bore. Dials are 0.3mm
thick in the centre and between 0.5 and 0.7 on the outside.
I only hope that my suggestins have given you 'food for thought'.
Cutting the chamfer won't cause you any problem with the way you propose
to do the job and my only concern is that you won't get a fair-face to
the 'top' if it is simply parted off.
That could be your next 'Project' :)
Just my cautious approach to anything 'photographic' but I would also be
concerned about oxydation which would be minimised by the application of
paint - I doubt that acrylic paint would be as thick as 20 microns but
you could try candle smoke to take away the 'bright' alum finish.
I look forward to your photo's of both production and finished article :)
JG
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http://www.revilloc.com/lens.jpg
