Richie's Mk1 Restoration

[RichardT10829]

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]

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

[RichardT10829]

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]

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

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]

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]

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]

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