Repair advice, please!

Thank you Pete. If I thought that I could produce a result half as good as that I would be a very happy bunny - sadly, I see it as very unlikely. Still waiting for a reply from Araldite but I get the sense that the adhesive companies (for obvious reasons) will be more concerned with commercial enquiries.

rgds

Bill

The casting cracked because of an excessive tensile load at that point.

Will an adhesive have a greater tensile strength?

If you have a lathe with a large enough capacity, you could possibly make a replacement from a block of steel.

A flycutter will mill the faces that need to be flat. A boring bar will produce the bore. A slitting saw on an arbor, between centres, with the job held on the Cross Slide or Toolpost, will produce the split. A similar set up of the job will allow the drillings to be made.

Not necessarily an easy or quick job, but not impossible.

And being steel, less likely to crack in the future.

Howard

If the item is a stand alone collar + necessary clearance/capacity the no reason it can't be made from two pieces of rectangular bar and bolted top and bottom...no need for slitting saws or milled faces.. Function over aesthetics...just bored and drilled.

pgk

Edited By pgk pgk on 27/05/2020 09:51:10

Would have been relatively easy when there was a foundry on nearly every street. High Nickel is the weapon of choice BUT, in this case, replace rather than repair. In clamping situations, there is no substitute for parent metal.

Regards Ian.

Hi all, the finest repair system I have ever seen for crack repairs of this type is the "Metalock Stitching System", no heat, no specialized welding equipment nor the skills to use it. System consists of a hardened guide to assist the drilling of a short row of holes at 90 degrees across the crack conducted with an electric drill, the stitch insert is a hardened steel replica of the crack & the row of holes at a slightly lesser pitch, it is fitted with a special tool called I believe a 2 pound ball pein hammer (other hammers are available), this drags the crack closed whether it likes it or not ! leaving it only to be tidied up smooth & painted over, have no idea as to availability these days, but have seen it used with complete success, I have set the hare running!

Bob H

Thank you all again, chaps. Some very interesting suggestions tempered by personal competence and age! Just had a look at robjon's suggestion - very impressive looking technique!

Howard's idea, particularly as modified by pgk, could be a 'goer' -certainly food for thought.

rgds

Bill

Bill, if you're completely stuck with an economical repair, I don't mind having a go at tig bronzing it, but I'm quite busy for the next week or 2, I also need to see if I can get my argon bottle replaced during lock down, shouldn't be a problem.

I've had my tig welder for a couple years now, but haven't had a chance or opportunity to try tig bronze brazing cast iron, so I can't promise you anything.

But if you decide you're out of options, let me know.

Those Metallock stitches are amazing. I've seen them used on cast iron marine engine blocks to close and repair cracks. In the old days they used to be furnace welded !

I've read about this in the past, seems like a great method of repairing cast iron, would you be willing to  use it on Bill's broken part and document the process for others to learn from?

Edited By Pete. on 27/05/2020 20:57:26

+1 for this

Martin P

Edited By martin perman on 27/05/2020 21:54:30

Hi Bill

My DW had the same problem , I made a steel lug which I placed against the broken one and welded it on , but this was 35 yrs ago now so I cant remember what rods I used now , i did it with my 185 amp oil cooled welder , but the repair has lasted since so it was a good weld ,ok actually it looked a bit like pidgeon sh*t but I tidied it up with filler when I painted it last year

Looking at vids of the metalstitching it's certainly an impressive process. But.. if used on a curved surface I'd assume you'ld need stitches of that radus? And close to the bolt lugs would be an issue too?

pgk

Yet again, many thanks for useful comments and ideas but very particularly for Pete's most generous offer. The extraordinary open-hand towards a total stranger is very special. I think the logistics would probably defeat me but, if you're ever in the North Norfolk coast area, there are several 'thank-you beers' in the 'fridge!

Again, food for thought, including a reply from Araldite suggesting a guarded ' would probably work, with careful preparation and the metal strengthening plate'.The 'metal stitching' would almost certainly be the most reliable but the process is (unsurprisingly) an 'inhouse' affair -i.e. not diy and undoubtedly expensive.

Kettrinboy's experience and the proven results sound extremely encouraging. I would be more than happy with that quality of finish although mine more likely to be much less elegant. Your short account of the process was much appreciated - any further hints and tips would be very welcome.

pgk - good point made adding to the 'ching, ching, ching' factor!!

rgds

Bill

If you can get hold of a copy of the May 2020 edition of the Vintage Motor Cycle Club's 'Vintage & Classic Motor Cycle' magazine you will find an article about Laser Welding. This appears to be a process which will solve your problems without causing further complications.

The article does say that it is expensive but worthwhile as result is like finding unobtainium!

The link to the welder in the magazine is http://www.e-m-p.biz/

One thing I would strongly advise against is using any form of adhesive as you will be asking a glue to have the same tensile strength as cast iron. If you use adhesive and it doesn't work you will have the devil of a job to remove it ready for any welding.

Good luck

Jon

Is it quite large? I was thinking you could post it, well the offer is open, all it'd cost you is the post to and from.

Have a think about your options, but I tend to agree with the above post in regards to adhesives, I think it will just waste your time and money, and possibly make other repair options more difficult.

Hi Guys,

Whilst modern structural adhesives are very good, you will note that where they are used, that use is built into the design.

I agree with others that say they shouldn't be used for this application. Personally I would simply re-make the part using steel.

Could I suggest that as AdrianR has noticed that the Mk2 version has a stronger casting and Kettrinboy has had to reinforce his when repairing it after his cracked, that any repair you contemplate such as welding or metal stitching that will leave the part as good as new or nearly so may not be adequate as the are indications to me that a design fault was recognised and corrected in the Mk 2 design?

Certainly adhesives, as good as these are today would probably not be a good choice in my opinion.

I think the only way to make the machine usable in such a way that it stays usable would be to remake the part, or have it remade as John Baron has already suggested.

A block of steel would perhaps be ideal and an improvement on the original, although cast iron is also available.

If it is of any help here is the drawing from the original Westbury article, but you would need to see if this part changed when the design was produced commercially as the Dore-Westbury. At a casual glance it appears not to have been, but please check.

Edited By Nick Clarke 3 on 28/05/2020 08:50:37

One of my quick change tool holders snapped in two. I silver soldered it , this was a few years ago and it's been fine. You can silver solder cast iron, use Tenacity no 5 flux.

Metal stitching was originally employed in repairing castings, where plugs are inserted into the casting to be an interference fit, putting the local cast metal into tension.

In this cased the problem is excessive tension, so would be unsure that such a repair would be effective, if not actually making the problem worse.

My vote is for replace, if possible, either by one piece, or as suggested, by clamping together two half pieces.

Possibly two fairly thick steel (say 3/8" ) half collars could be made, to fit over the casting, located by longer bolts passing through the existing holes, so that the clamping forces are actually applied by the steel compressing the cast iron.

Howard

Jon, Pete, John and Nick thank you. Your caveats re adhesives have been taken on board and that option moved to the bottom of the list. Nick., I have a set of original drawings, so could work from those.

John R - sounds like a possible option but I would see the need for some serious heat producers - e.g.Sievert or Rothenberger rather than my camping gas jobby.

Any way thank you all again - excellent brain food and I 'll let you know what results. It might even be a return to the present Zero Clips arrangement!

"Zero Clips"?? ... the black ridged item on the left hand end of photo 1. It is one of several (for me) 'must have' workshop items - a bodgers 'go-to'. The black ridged item is the basis for a plastic 'Jubilee Clip' which has a similar material securing collar producing an extraordinarily high clamping force. They can be joined to produce any length needed and I have (confidently) used them in the past as life-line type supports. The one in the photo has been used as a stop-gap clamp across the cracked area and has withstood all imposed loads, so far. The search for repair methods is to do away with such an obvious 'bodge!

rgds

Bill

Edited By Cornish Jack on 28/05/2020 09:42:11