Richie's Mk1 Restoration - Page 9

Richard Farrant · #**241** 09-01-12, 21:38

Quote:

Originally Posted by ajmac

Lets face it Rivets are so 19th century! Welding rules, british industry just wasn't forward thinking, the T16 showed the way and in the end the UC was welded too. From a restoration point of view rivets do offer an easier route, putting new armour on a welded carrier and having the welds look factory would be more difficult I imagine.

Rivets are superior to bolts, because they swell in the holes and stop any movement between the two parts, if bolted, to get the same rigidity, the holes would have to be reamed to fit the bolts. This was why chassis repairs on lorries, where a riveted spring hanger had to be changed, had to have the holes reamed for special bolts if hot riveting was not possible (I know, been there years ago).

Lynn Eades · #**242** 10-01-12, 05:53

The carriers must flex while travelling cross country. A carrier bolted together would never last as long, bolted. They would work loose at the joins unless each hole had been reamed as per Richards post.
Thats the structrual side.
Now for the asthetics. Rivets win by a country mile in every posible way. They are classic!!, with so much character!!!!.

(Sorry you T16 guys) I have a welded hull AOP, which was the only carrier I could find, while hunting for a riveted one.
Riveted bridges were still being built in the 1960's (Auckland harbour Bridge, built by a Japanese company)
I just love riveted structures.

I use the same legal defence as Shaun. Its my opinion (everybody has one)

horsa · #**243** 10-01-12, 06:07

Rivets were a manufacturing method used all over Canada and the UK (and really everywhere else) during the war and was the fastest and easiest way to employ a large percentage of the available workforce to speed up production. The USA had started new techniques welding Liberty ships and was able to turn them out faster than when they had been riveting. The T-16 was produced after that time so was able to take advantage of it while automatically gaining a relatively water-tight hull for possible amphibious use.

I still also prefer the rivet look myself but alas, it wouldn't be correct for my carrier. Course the T-16 has a stronger hull whereas other models had the easy opening feature.

Lynn Eades · #**244** 10-01-12, 06:27

I would suggest the "easy opening feature" is not restricted to the riveted carriers

shaun · #**245** 10-01-12, 09:06

Gents i will ref to our conversations at the next party i attend , we are all true rivet counters ! Rivets rule !

RichardT10829 · #**246** 10-01-12, 11:00

Quote:

Originally Posted by horsa

Rivets were a manufacturing method used all over Canada and the UK (and really everywhere else) during the war and was the fastest and easiest way to employ a large percentage of the available workforce to speed up production. The USA had started new techniques welding Liberty ships and was able to turn them out faster than when they had been riveting. The T-16 was produced after that time so was able to take advantage of it while automatically gaining a relatively water-tight hull for possible amphibious use.

I still also prefer the rivet look myself but alas, it wouldn't be correct for my carrier. Course the T-16 has a stronger hull whereas other models had the easy opening feature.

I cant recall but i am sure this one was either hit by an 88 shell... or struck an anti tank mine... they all peel open one way or another lets face it with the size of round being fired at them the 10mm front plate was like having tracing paper as a shield...

well back to the grind stone... speaking of which my die grinder and roloc discs should be arriving today.... i cannot put off moving my big compressor any longer....the thing weighs a tonne like a mini sub ! need to go turn out a few snaps then harden them.... an engineer i know was saying to quench it in Brine rather than oil as it pulls the heat out faster..... that combined with heating the steel up until its glowing then roll it in carbon...then re heat and quench...

anyone else heard of this ?

tankbarrell · #**247** 10-01-12, 11:05

The ability of low grade steel to be hardened is related to its carbon content. Rolling it in carbon powder and reheating will case harden it. To harden throughout followed by tempering requires a steel with a higher carbon content than mild.

It will depend on what you make your snaps out of. I make mine from EN24T and do not harden further. All my rivetting is done hot and this works fine.

Lynn Eades · #**248** 10-01-12, 11:34

How would the EN24T compare to 4140 or 4340. Personally,I wouldnt waste time making one from mild steel.

tankbarrell · #**249** 10-01-12, 11:46

EN24T and 4340 are both chromium nickel molybdenum, 4140 being closer to EN19.

RichardT10829 · #**250** 10-01-12, 12:36

can it still be turned without special tools on the lathe ?

tankbarrell · #**251** 10-01-12, 12:39

Are you using HSS or carbide tips? Tipped tools have no problems, HSS is ok if you keep an eye on your speeds and feeds.

RichardT10829 · #**252** 10-01-12, 12:45

no idea not my lathe...will ask the lad Adrian... cheers

Lynn Eades · #**253** 11-01-12, 06:56

To pose the question a little differently, Are the cutting tips on the tools separate, as in clamped into the holder (Not the tool post holder) Commonly a triangle shape, that can be turned over, and around to give six cutting edges?
Thanks Adrian for your conversion.

RichardT10829 · #**254** 11-01-12, 17:43

got the bar today.. such a nice piece of steel ! seems a shame it chuck it in a lathe... will keep you updated with how it turns out ! fingers crossed the HSS bits will cut it without it killing them off...

finally managed to get the cam plate fully out today... just a quick question.. the two caps that are on the cam plate (which go around the axle) do these bolt up solid to the axle or does the axle slide/pass through them ?

Dave Page · #**255** 11-01-12, 19:23

Hi Guys,
the welding of armour plate was pioneered by Guy Motors, they proved that it could be done along with substantial saving of time and materials. The process they developed was then handed to the War Dept., gratis. Imagine a company doing that today.

Rivets look good, and if one knows how much work there is in each rivet, even little ones, the appreciation factor registers much higher.

As has been pointed out, any decent-sized projectile hitting a rivetted or welded hull may make life for those inside rather grim.
Cheers,
Dave

Lynn Eades · #**256** 11-01-12, 19:37

3 through bolts countersunk head,bottom side, that hold the two plates and the cam plate sandwiching the bearing.

RichardT10829 · #**257** 11-01-12, 22:30

ah.. mine came out leaving the caps on the axle with the rollers... the cam and plate came away seperate.

Lynn Eades · #**258** 12-01-12, 04:54

Yes. thats what should happen.

RichardT10829 · #**259** 13-01-12, 17:46

Well work continues while i wait until the snap is done... i managed to get the cam plate out (as previously mentioned) and the caps off the cross tube, also managed to get the front idlers off however they needed some heat applied to the nuts before she would let go.. once off they were given a good clean... the gunners side of the lower hull has been wired down with a grinder and mandrel, along with the idler for that side... work plods on, but now she is in a state where as soon as the rivets are banged in she can be etch primered stem to stern and rebuilt ! i have not been able to get the cross tube to move so will need to strip the rollers down etc this will get done tomorrow (unless the snap is ready in which case i will be straight on with the rivets)

here are some pics

rebuilt however needs new bearings..i have ordered three..one for each roller and one for the spigot on the cam plate they are all the same 6305's

cam plate has since been stripped down and de rusted ready for its new bearing, etch primered and painted.

lower hull meets cleaned idler unit..both wire mandrelled to an inch of their lives

Ron Pier · #**260** 14-01-12, 11:20

So Rich, a bright and early start with the rivet gun..........That'll get the curtains twitching over the road

Ron

RichardT10829 · #**261** 20-01-12, 14:32

well the snap was done today, I did the easy end and Bill did the business end, i learned loads from him today so my greatest thanks must go to him.... we discussed about how hard the metal actually is, it may still need hardening..mine will be a test bench...he has the facilities to make further snaps for those that need them..and now that he has a pattern he can turn them around quite quickly so folk that want any just shout up and we will get something sorted....they are quite light weight so postage is not expensive they can be made by him to specification ie length...diameter of rod...shank size etc etc...

The lower hull has now been etch primed... cam plate and rollers rebuilt and painted... just need to get her buttoned up now and she can be base coated and rebuilt.

RichardT10829 · #**262** 20-01-12, 17:17

been doing some research on the EN24T..... here are the findings.... Adrian how long has yours lasted ?

Quote:

EN24 and EN24T Steel

BS970: 1955 EN24, BS970/PD970: 1970 onwards 817M40.
Related European grades: 34CrNiMo6, Werkstoff No. 1.6582
US Grade: SAE (AISI) 4340.

EN24 is usually supplied in the finally heat treated condition (quenched and tempered to "T" properties) up to a limiting ruling section of 250mm, which is superior to grades 605M36, 708M40 or 709M40 - see properties below. Please refer to our selection guide for comparisons.

EN24 is a very popular grade of through-hardening alloy steel, which is readily machinable in the "T" condition. (Refer to our machinability guide). EN24T is most suitable for the manufacture of parts such as heavy-duty axles and shafts, gears, bolts and studs. EN24T can be further surface-hardened typically to 58-60 HRC by induction or nitride processes, producing components with enhanced wear resistance.

In addition to the above, EN24T is capable of retaining good impact values at low temperatures, hence it is frequently specified for harsh offshore applications such as hydraulic bolt tensioners and shipborne mechanical handling equipment.

EN24 sections larger than 250mm may still be available in the quenched and tempered condition, but it should be noted that a fall-off in mechanical properties may be apparent approaching the centre of the bar.

It is therefore recommended that larger sizes are supplied in the annealed (softened) condition, and that quenching and tempering is carried out after initial stock removal. This should achieve better mechanical properties towards the core.

817M40 (EN24) Specification
Chemical composition
Carbon 0.36-0.44%
Silicon 0.10-0.35%
Manganese 0.45-0.70%
Sulphur 0.040 Max
Phosphorus 0.035 Max
Chromium 1.00-1.40%
Molybdenum 0.20-0.35%
Nickel 1.30-1.70%

817M40 (EN24) - mechanical properties in "T" condition
Max Stress 850-1000 n/mm2
Yield Stress 680 n/mm2 Min (up to 150mm LRS)
Yield Stress 650 n/mm2 Min (over 150 to 250mm LRS)
0.2% Proof Stress 665 n/mm2 Min (up to 150mm LRS)
0.2% Proof Stress 635 n/mm2 Min (over 150 to 250mm LRS)
Elongation 13% Min (9% if cold drawn)
Impact KCV 50 Joules Min (up to 150mm LRS
Impact KCV 35 Joules Min (over 150 to 250mm LRS)
Hardness 248-302 Brinell (850-1000 n/mm2)

EN24 Equivalents
BS970: 1955 EN24
BS970/PD970:
1970 onwards 817M40
European 34CrNiMo6
Werkstoff No. 1.6582
US SAE (AISI) 4340

KV Steel Services is a supplier of EN24 steel to local and national businesses. We stock EN24 in bright bar and blocks and black bar, square, flats and blocks.

tankbarrell · #**263** 21-01-12, 09:33

I've set a few hundred rivets of all sizes from 1/4" to 3/4", all but the 3/4" with home made snaps with no problems at all.

RichardT10829 · #**264** 06-02-12, 23:07

well i said i would post up after trying a few rivets... my pal Kris came down tonight and and we set three... the first one...for reasons beyond me i thought my setting length was too long (dispite the rivets being cut to length at source) so chopped 5mm off.... results were... too bloody short ! second rivet (the one in the middle) i left alone and it set perfect ! third rivet (to the left of the good rivet next to the centre bulkhead) i got 3/4 set then my compressor blew a valve or something and dumped 75ltrs of air in about 10 seconds flat (and i filled my pants) so did not get it to set fully... all be it its there or there abouts. i found the trick is to get the rivet heated until it is just about to sparkle them wham it home.

so order of the day is to service my compressor (or whats left of it) and i can get cracking

Philliphastings · #**265** 07-02-12, 06:13

Hello Richard thanks for your ongoing and informative posts, it's still a while before I will be ready to do the rivetting (still have to buy, cut and 'age' some of the steel plates) but I will be in need of a snap for sure.

Cheers

Phill

shaun · #**266** 07-02-12, 08:45

Looking good !!!!!!!!! My phone has stopped receiving photos for some reason Richie - i had a feeling new rivets were what you texted last night. Are you down this way at Easter ?

RichardT10829 · #**267** 07-02-12, 09:12

yes matey... so you and Kev need to hurry up if you are buying carrier spares from up here if you want the annual delivery this year hahahhaa.....I have a pair of wheels and a gearbox to drop off at Martyns on my way down.

looked at the compressor today and it appears that the receiver has failed where the bypass valve sits... has rotted from the inside...mind the thing was made in the 1950's so it has lasted a good while....will change out the receiver and get cracking again asap.

dont think i have ever been so frightened !

Lynn Eades · #**268** 07-02-12, 11:27

I heard about one that demolished a shed, when it blew.

eddy8men · #**269** 07-02-12, 22:59

fair play to you richie for having a go at riveting your hull, it's a shame you couldn't get more done before the compressor blew but at least you have time to take in any lessons learned.

good luck with it

rick

Marc van Aalderen · #**270** 07-02-12, 23:25

Richie, Great job! How many do you have to go? I think I will order a set of snaps through you too. There are some rivets missing on my carrier.
You make it look easy so I will have a go at it.

Keep up the work, only 5 months to Beltring!

Cheers mate,