Reproduction UC Track availability?

[matt_mcleod]

Hello gents,
Please permit me a brief introduction in my first post. I am a chartered mechanical engineer in Australia and hold a financial interest in an engineering shop in Ballarat, Victoria. We complete engineering and machine shop jobbing for automotive, transport, agriculture and manufacturing businesses. We have a keen interest in keeping old machines running, and personally, my interest is in Australian cars from the 50's.

A colleague who is restoring his own Universal Carrier alerted me to this thread just after it started. My business has contacts in metallurgy, pattern making and NC machining so we decided to invest a few hours to see whether it might be economical to manufacture repro UC track. I also spent 12 years working for Caterpillar so I have a reasonable knowledge of the engineering of tracked machines.

We secured one unused link and contacted our pattern maker. His birthdate pre-dates Universal Carriers and his knowledge is encyclopedic so I greatly respect his professional opinion. We have a copy of Nigel Watson's UC reference text describing the use of manganese steels, cast steels and malleable cast irons. Our pattern maker assures me these materials were used because they were the best technology available at the time. Based on the low utilization of restored carriers (ie who would do 100 miles in one year in their carrier?), his suggestion is a tweaked 500/7 ductile iron, which will suit the job and is relatively cheap. I don't believe there is any good technical reason for attempting to replicate the original material as this will only increase the price.

His iron foundry work is completed in China as he has not located a foundry in Australia able to compete. Our pattern maker has his own business manufacturing brake components for automotive and earthmoving equipment, and has assured us of a first class casting. With his own business and reputation on the line, I have to believe him. The pattern is quite complex, as has been discussed in detail above, and accounting for shrinkage with the given material is where the skill of our Chinese friends will come into play. We are investigating a sample run and trying to keep this as cheap as possible.

We are attempting to determine an ex-works price from our workshop in Australia for assembled field service track sections to suit a single machine (obviously to make manual handling the link sections safer when they arrive at its destination). Tooling costs have already been supplied from China, and are in the vicinity of US$2500, so this is not a cheap proposition. I have piece prices from one supplier (pre-drilled for the pins) ex works in China so I need to work out shipping and duties over the next couple of days.

I do need some help from the forum, however. The track pins, according to Mr Watson, are hardened along most of their length to permit the free end to be peened. I have one pin, but the end was ground off to free it from a track. What is the free length of a new pin, from one end to another? I have estimated 10" under the domed head to the plain end, based on the track link being 9.5" wide and allowing for peening or split pinning. Any thoughts from the forum?

Anyway, we have plenty still to do to determine a price, but would be interested in comments from the forum members. Obviously the more interest, the cheaper the parts will be, as we would amortize the tooling, shipping and duties over the entire run. I'm thinking about enough links and pins to supply new track assemblies for 20 machines, on the assumption there are at least 20 guys somewhere around the world who want (need?) new tracks for their carriers.

Oh, and these would be English pattern links. I understand the Aussie links were different due to a wider bogie wheel.

Here is a link to our website, you can see our equipment and local engineering and machine shop pricing, plus links to our contact details and LinkedIn profiles.

Regards,
Matt McLeod

[Lynn Eades]

The Aussie track uses a shorter straight plain pin. At the inner end, the hole is smaller. This allows the pin to be punched out, whilst being retained. The other end has a recess with a groove in it. This end is lead plugged. Punching the lead plug in, expands the plug into the groove, thus retaining the pin. The lead is soft enough to fail, when the pin is punched from the inner end.
With English or Canadian track(essentially the same specs) the pins are as per your description. The track sections are assembled into 21 link sections, and joined with pins, that are located with a washer, and split pin I have a number of these pins, and can supply a sample if you wish.
Be aware that the track has quite a tolerance between the links, and requires this side clearence, to allow the track to displace sideways, allowing the machine to turn. The double bogie assembly moves 3/8" each way from centre. I would estimate that the track would need to achieve this over about 16 links (the number of links between the front bogie, and the 2nd bogie wheel)

[matt_mcleod]

Hi Mr Eades,
Many thanks for the extra detail. Yes, I was aware you steer a UC via the bogie, not like an earthmoving machine which is turned via track speed differential.

We'll work on the assumption that the sample link we used for the pattern will give us the correct clearances to permit the UC to turn, but will verify with samples, if the project goes ahead.

I'd appreciate a sample, but some measurements with a vernier caliper would suffice if you can help. Otherwise, I'd be he happy to purchase a pin/washer/split pin from you to ensure we have accurate basis for any reproduction. Let me know what works best for you.

Thanks again,
Matt.

[Lynn Eades]

The nominal length of the pin, from the shoulder under the head is 250mm (of 22 pins, they vary from 248mm to 253mm.
Shoulder to centre of split pin hole is 246mm to 247mm.
I have one pin wth a change of colour at the 241mm mark.
The diameters vary around 0.4375" (7/16")
Some are marked "L" (maybe Leys U.K.) others are marked "V.P 1943",one is "N 2/3, and others are plain.
Some are black, while others are bright steel.
Anything else just ask.
Oh, and Matt, Red, Lynn, or Bluebell will do fine.
,

[Philliphastings]

Hello Matt and welcome to the forum. What you are proposing is indeed exciting news for non Australian Carrier restorers...

Cheers

Phill

[RichardT10829]

Yep you got my pulse racing if there is anything i can do to assist let me know

[matt_mcleod]

Hello gents,
Thankyou for the public and private messages of welcome and support for our investigation.

I had a look at a couple of carriers yesterday, both for the tracks and to help a friend draw up the front armour plates for reproduction (if anyone is interested in these drawings I will send copies when they are finished).

I also re-measured a couple of brand new links to clarify the pin bores. My measurements would indicate the bore in the link is nominally 0.5mm greater in diameter than the maximum pin diameter.

ie (according to Nigel Watson's text) the new pin diameter is allowed to vary between:
Max 0.437" (11.10mm)
Min 0.432" (10.97mm)

My measurement of a link bore (taken three times) averaged out to 11.6mm. If anyone has a link lying around and can take a measurement to confirm this as a suitable target diameter for the bores - that would be great.

On the topic on pins, I had a discussion with our patternmaker who has contacts at Ajax Fasteners here in Australia. We will ask them for a quote, and have also sent a pin drawing to China.

We have had a number of discussions regarding pin materials and pin retention and would be interested in some feedback from the forum. As was mentioned above, I understand the pins were case hardened along "most" of their length. This would have been done for wear resistance, but still allowing the softer end to be peened over.

Frankly, heat treating pins adds another sub-contract operation which means more cost. We have considered using a high carbon steel like 1040 in an attempt to maintain some surface hardness without adding another manufacturing operation. With the expected use of restored carriers in mind (ie they are not in war service) we propose this will provide a cost-effective alternative.

With respect to pin retention, there are a number of options. The NOS track I inspected today used a small collar on the straight end and appeared to be simply peened over with a hammer. Nigel's book shows factory tracks having a domed, riveted head. There is also mention of "welded caps". Service track sections are joined with split pins. Aussie tracks use lead plugs.

Here are the pros and cons of each (from a manufacturing perspective):
[1] Collar/peened: Pros - cheap and easy, Cons - lots of labour, assumes 1040 high carbon steel can be peened in this manner (we'd have to make a sample pin and try it)
[2] Domed/riveted head: Pros - very strong, Cons - needs special tooling to achieve, would have to sub contract and ship big heavy link sections around
[3] Welded Caps (using a collar as per [1] and TIG welding the collar to the end of the pin): Pros - strong, relatively cheap, Cons - can't think of any
[4] Split pins: Pros - easy to assemble/disassemble, could be assembled by end user, pack tighter in crate for cheaper shipping, Cons - Retention relies on a small split pin
[5] Lead plugs: Pros - can't think of any, Cons - another part, another material, more cost, questionable whether we can reproduce the dimensions and achieve acceptable pin retention.

On the topic of strength using split pins, I don't believe this is valid option. When turning the carrier, the track is curved and hence the forces generating the turn are transferred to the washer and therefore the small split pin is loaded in shear. This would be acceptable for joining service link sections, but I would consider this poor engineering practice if used to join all the links.

My preference is for [3] Welded caps, but interested in the feedback from members. If this was selected and if the repro track manufacturing goes ahead, I would propose service link sections would be pre-assembled and stacked in a custom-built crate for shipping. End users would then assemble the service link sections with split pins as per original supply.

Anyway, enough for today. Would appreciate any thoughts, feedback or comments.

Regards,
Matt McLeod