Advice needed for metal repair

Planapo · Post by **Planapo** » Sat Feb 14, 2009 6:30 am

Hi guys,

Recently I was lucky to purchase a nice Newport linear stage for an attractive price. Included in the lot was a large heavy lens element mounted in a big metal loop and a large 90° angle bracket. Together these parts must weigh about 2-3 kg. So you can imagine that this has to be packed solidly with good cushioning, which I explicitly pointed out to the seller prior shipping.

Nevertheless, this moron of a seller squeezed the lot into a tiny cardboard box and gave it just one layer of bubble wrap thinking that putting a sticker on it "Electronic equipment, do not throw!" would help. As you can imagine, things went according to "Murphy´s law" meaning ##### happens, and another moron came along, this time from the parcel service, and must have dropped the flimsy box. D-a-m-n!

However, things didn't turn out to be as bad as expected: Just the ear/bracket that fixes the actuator to the stage broke off. Miracolously, all other things, even the glass of that heavy lens element, are undamaged! Most important, the stage itself is still in mint condition, as is the actuator which is, to my utmost surprise, totally straight, has no dents, and is running, like the stage, totally smoothly.

But as this broken mounting ear/bracket that holds the actuator is fixed to the stage by two screws, I thought this should be available as a spare part, and luckily it is. Just the price of 17,60 Euros plus VAT and the shipping costs, especially if I had to have it shipped from the US, would add to a sum at about the price or more than I paid for the whole lot in the first place.

However, I have heard that even when building airplanes, the metal parts are sometimes glued together, and as this broken ear/bracket just broke in one, "clean" fracture, I wonder if it couldn't be repaired with a special type of glue?

Hence this post and my question to you guys out there, more andvanced in metal work: Do you think it could be repaired soundly by glueing. It looks to me as it is made of some kind of cast alloy.

Can you recommend a special glue for this job, or won´t it be solid enough with glue?

What do you think? As always, I would be grateful to read your appreciated advice.

--Betty

Here a snapshot of the broken ear/bracket

AndrewC · Post by **AndrewC** » Sat Feb 14, 2009 8:49 am

JBWeld - it is a metal epoxy but can be hard to find over here (loads of it on eBay and I can testify to the strength even when badly mixed, I once "welded" some tools to the bottom of my tool box)

http://www.jbweld.net/products/jbweld.php

Mind you, depending on the load, superglue might work just as well and if it failed it wouldn't be a catastrophe.

Andrew

AndrewC · Post by **AndrewC** » Sat Feb 14, 2009 9:00 am

If you do weld / glue it take the micrometer out of the housing first

Andrew

Stevie · Post by **Stevie** » Sat Feb 14, 2009 9:14 am

If it was me i would replace the actuator mounting block .
http://search.newport.com/?sku=AB-3
JB weld would be my plan B though .

rjlittlefield · Post by **rjlittlefield** » Sat Feb 14, 2009 10:56 am

I'd start with the superglue (cyanoacrylate). This break has a lovely texture of small crystals that will register the two halves together and will also absorb quite a lot of shear stress. All the glue needs to do in this case is keep the two halves from separating. Cyanoacrylate will go in very thin, not interfere with the crystals fitting together, and I think will be plenty strong for this application. If that's wrong and it comes apart, then you just clean off the old cyanoacrylate with solvent and move up to epoxy.

--Rik

PS. You have my sympathy about this problem. See HERE for my own incident.

AndrewC · Post by **AndrewC** » Sat Feb 14, 2009 12:00 pm

rjlittlefield wrote: ... See HERE for my own incident.

The wood is probably Iroko - very distinctive endgrain but can split along the grain. Your best wood for this use is lignum vitae or one of the hard as rock Oz acacias

Andrew

elf · Post by **elf** » Sat Feb 14, 2009 12:16 pm

I'd add a mechanical fastener (machine screw) after gluing with either superglue or epoxy. The screws in eyeglasses would probably be the right size and they're usually self-tapping. My optometrist gave me several free for another project.

If there's room for 2 screws it would be even better.

Harold Gough · Post by **Harold Gough** » Sat Feb 14, 2009 12:33 pm

AndrewC wrote:JBWeld - it is a metal epoxy but can be hard to find over here (loads of it on eBay and I can testify to the strength even when badly mixed, I once "welded" some tools to the bottom of my tool box)

In the UK such products are available from car parts shops (not the dealers' parts departements) which retail to DIY car servicers and repairers.

For a couple of years I have been using Gorilla Glue where a strong repair is essential.

http://www.gorillaglue.com/

http://www.gorillaglue.com/glues.aspx

Harold

rjlittlefield · Post by **rjlittlefield** » Sat Feb 14, 2009 12:47 pm

AndrewC wrote:The wood is probably Iroko

Thanks for the ID. I would not have guessed that. Our samples are all much darker, even when freshly cut, than any of the images shown for Iroko at http://www.hobbithouseinc.com/personal/woodpics . I'm glad you recognized that distinctive endgrain.

--Rik

Planapo · Post by **Planapo** » Sun Feb 15, 2009 12:54 am

Thanks guy for all the good information!

I will give it a go with glueing then, and found the glue brands you've mentioned to be available locally or on British eBay.

Rik wrote:

PS. You have my sympathy about this problem. See HERE for my own incident.

Thanks, Rik! It's always infuriating when one has extra hassle and work that could easily have been avoided but now has to be dealt with just because of other people's stupidity and gross carelessness, isn't it?!

elf wrote:

I'd add a mechanical fastener (machine screw) after gluing with either superglue or epoxy.

Yes, I'd wish I could do this, but don't have access to precision tools to drill fine (threaded) holes into the metal for two of such stabilizing little extra screws.

Andrew wrote:

If you do weld / glue it take the micrometer out of the housing first

Yeah, good point!

But there is this nut that presses the micrometer against the broken-off ear of the mounting block. It´s the nut with these two opposed slits you can see in the next pic.
I have no clue how such a nut is screwed off and don't want to damage the nut by sticking a screwdriver or something alike in one of the slits and use it as a lever. Can anybody tell me what kind of wrench or other tool is meant to be used for (un)fastening such a double slitted nut?

--Betty

AndrewC · Post by **AndrewC** » Sun Feb 15, 2009 3:04 am

That nut probably isn't very tight - try just gripping it with some rubber gloves and see if that gives you enough force. Otherwise tap gently with a screwdriver against the slot as you already thought

Andrew

NikonUser · Post by **NikonUser** » Sun Feb 15, 2009 5:35 am

Betty:You need an Optical Spanner Wrench
http://www.newport.com/Spanner-Wrench/1 ... GgodWUG_cQ

Try a camera repair shop, jewellers or watch repair place and ask them to remove it (for free) and then get them to tighten it later

elf · Post by **elf** » Sun Feb 15, 2009 11:26 am

Tapping isn't required and the only "precision" equipment needed is a pin vise and the drill bit. Neither of these should cost more than a couple of $.

Here's an example: http://www.widgetsupply.com/page/WS/PRO ... eler/BLU01.

Even drilling and gluing a pin in the hole would make the joint stronger.

AndrewC · Post by **AndrewC** » Sun Feb 15, 2009 12:54 pm

Don't bother buying stuff unless you need it for other projects.

1) Try and take off the micrometer using a kitchen glove for grip on the nut
2) if that doesn't work just wrap the micrometer body in cling film
3) as Rik (?) pointed out, it is a nice crystalline surface, in other words lots of area for the glue and the structure will help it resist shear forces, so just go for it with a couple of drops of superglue.

Remember, the more you poke at it the less chance of a good glue joint. Try dry assembling once, then the glue, keep it squeezed together for 20secs and then leave overnight before testing it.

Have fun

Planapo · Post by **Planapo** » Sun Feb 15, 2009 1:51 pm

Thanks guys for your further support!

Right Andrew, I will start with the simple approach first. Unfortunately the nut is screwed on quite tight, I think something like NU showed is needed.

But I do appreciate to learn a bit about metal work, so thanks for mentioning the "pin vise", elf. Do I get this right that these holes are drilled by hand with this "pin vise"? I had thought one would need a drill press. But I still can't figure how it is operated be hand to get the lots of rotation though... Maybe like the Brownie Scout's way of fire making with dry sticks? Doesn´t that give one blisters until the hole is done? (If you ever want to know how to knit socks or a jumper, feel free to ask me

).

Nonetheless things are still getting a little more annoying: Just tried to screw off the broken base of that mounting block but none of our hex/Allen wrenches wanted to fit in these screw heads ...

Dang! All of these screws and threaded holes on that table seem to be non-metric!

Hope the local screw dealer has such exotic non-metric hex wrenches... last time I got ripped off there when buying whitworth threaded screws to fit in 1/4" or 3/8" threaded holes of camera gear..

--Betty

- having fun