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3-inch HE Bomb Restoration Advice

P

peregrinvs

Well-Known Member
Hi,


I have this incoming semi-relic 3-inch HE bomb as a restoration project. (seller's pictures) I'd now appreciate some advice on how 'doable' this is as British mortars are a fairly new area for me.


The obvious problem is the missing fins. How difficult would it be to transplant on a replacement? (It believe they were tack welded) It occured to me that an unrotted fired tail unit might be a good donor. Alternatively, how rare are complete tail units?


Then onto fuzes. I believe a No.162 fuze is correct for this and there's also a fuze adaptor? How difficult / expensive are these to find?


Thanks,
Mark
3-inch mortar - 1.jpg3-inch mortar - 2.jpg3-inch mortar - 3.jpg
 
That item appears to hardly need any work at all. Just sand blast and paint. Making a new fin is easy also. Just simple metal working and welding skills required.
 
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The fins come up now and then. The fins are spot welded to the center in a jig. It looks like you need an adapter for the 162 fuze which do come up now and then. Plenty of fuzes about still with their cardboard packing. As for finish, if you want a HE version you need to clean back the body and fin till its shiney new as if it came out of the press, as to say, factory finished before painting and shelac it by spraying to give a light to dark brown finish and oven dry it, as they done the originals. I believe the windage band was not coated, not sure but at least one coat, and then banded green and red on a rotating jig by hand with a paint brush and hand stenciled with the usual markings etc.
 
That looks a good one i would just get it back to bright steel and just use shellac of finish it, it will look like this.
 

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To be strictly correct you should obtain Fuze DA No 162 Mks 1/2, 1/3, 4, 4/1, 4/2, or 8. All other Marks were either for Bombs 4.2, for India only or were never produced.
The tail units may be arc welded, spot welded, projection welded or brazed.
Most of the spot welded tails had 5 spots and the projection welded tails had 8 welds.
 
Now received and here are some pre-cleaning pictures. I’m not currently thinking of trying to fabricate replacement fins as I simply don’t have that sort of metalworking kit. My initial plan is to clean it back to bare metal and unscrew the tail unit. I can sort out the shellac finish and paint markings while I wait for the other parts to turn up.
850BC3F2-2E63-40C2-AF34-0E29CC87B9BA.jpg64F2BC30-97B2-4DC0-BAD2-C6F38EA688C5.jpg37EAF0B0-051D-46BA-9B0C-F18CD95CFE4C.jpgB0B6BBE0-590A-4BCD-9737-A5B9CCFBFF1A.jpg
 
At last! :tinysmile_grin_t:

The tail unit really didn’t want to come off and this is the end result of a great deal of heat, penetrating oil and brute force. (Especially the latter) I can now proceed to fully restore the body pending sourcing the other parts at some point. Of the latter, I have had no success at all, so all leads very gratefully accepted.

A few questions:

- Was the metal band around the middle left bare?
- Was there a fuze socket filler plug for these?
- Is shellac or walnut varnish better for the body finish?

Thanks,
Mark

58AEA080-4DE5-47FE-AE96-206971418246.jpg7AE33DB3-CEC1-4E53-A38B-7721A182CDD7.jpg94CF855E-126D-41A3-85FA-4A9ED750DB91.jpg
 
Cleaned, polished and coated in shellac. It’ll look a bit more interesting when I’ve put the red and green filling bands on it. I’ve also found a chap on eBay who does 3” HE mortar stencils.

Still curious to know if there was a fuze socket plug for these? It would be an improvement over an empty hole if I don’t find a fuze.
 

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My Australian fuze plug is black bakelite and is 65.5mm long.
No 6 AUST 1E 1952. Quite common so you should find a UK example for your mortar.
 
Which system are you using for the bomb markings?
Pre '44, '44 - '48 or '48 - '51? They are all slightly different.
The bomb bodies were originally coated with lead free copal varnish and baked. Repaired bombs were shellacked
The bands are not varnished, but treated with lanolin to reduce friction on firing and prevent rusting in storage.
 
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AE501
Thanks for the BB identification in my thread.
The Aussie 3" mortars I had (12) were all varnished completely including the bands. Made by J&W 4/45. Why different to UK ?
 
Having dug back to a 1942 reference it says "bombs are varnished" with no reference to bands.
The varnish is that thin and baked, I doubt that there would have been any residue in the mortar barrel.
The first reference was 1953, by which time quality control and more time, would have come into play.
 
The next snag. I bought this fuze adaptor and filler plug from another forum member for my 3” mortar body, but it is too small to screw into the neck of the bomb. There is some corrosion damage to the neck threads, but not enough to account for how loose the adaptor is. Is it the wrong fuze adaptor? Did they come in different sizes? Could the neck have expanded in a partial detonation? I can make it cosmetically fit with a discreet spacer, but it would be good to identify what the problem is.

Thanks,
Mark
DF29E773-89FB-4C3F-9474-E933AED7BB1B.jpg
 
What you have there is one of several 3" Mortar Nose Containers. It could be that your particular bomb body mark requires a Nose Adapter No 1 or 1/1 which are much shorter but are only used with certain body marks.
 
AE501 said:
What you have there is one of several 3" Mortar Nose Containers. It could be that your particular bomb body mark requires a Nose Adapter No 1 or 1/1 which are much shorter but are only used with certain body marks.
Click to expand...
Thanks. Interesting. The markings on the bomb body are a bit jumbled and indistinct, but there's what looks like a numeral 'III'. There's possibly also a 1940 date.
 
I thought it looked like Roman numeral III which would make it pre October 1944.
This was before Nose Containers were introduced, therefore it would have had one of the Nose Adapters.
 
AE501 said:
I thought it looked like Roman numeral III which would make it pre October 1944.
This was before Nose Containers were introduced, therefore it would have had one of the Nose Adapters.
Click to expand...
Thanks. There's someone on eBay currently selling repros of the earlier short adapter and I've messaged them for some measurements. Is there a reference anywhere for the sizes of the 3" bomb body types and fuze adapters?

A play with a ruler suggests the neck pocket of the bomb is about 43mm wide and the external diameter of the threads on the fuze adapter is about 41mm.
 
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The previously mentioned nose adapters were made specifically for your bomb and 4.2" bombs, so any properly made copy should fit.
The fuze pocket is 1.385" high and 1.376" low at 14 TPI to take fuzes with a 1.375" 14 TPI diameter.
 
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