Meehanite Cast Iron Available Locally?

[carrdo]

Hi All,

Does anyone know where one can source true meehanite cast iron in small quantities? I have a very small high performance piston to make which will be chrome plated and I need the real thing not something which is close for this application. A 3/4" dia round bar 6" long would be ideal but I can buy a larger amount if needed.

 

[YotaBota]

Where is local or does it matter?

I can't help with the cast but knowing your location may help others who can help.

 

[carrdo]

Hi Mike,

I am in Toronto and local can be anywhere in Canada.

 

[PeterT]

My original post got corrupted under what looked like site maintenance? Links reconstructed.

Cast Iron

MES is here for the benefit of the Model Engineer with over 30 years experience in the operation of miniature Road and Rail locomotives. We provide Model Engineering Supplies, Metals, Tools, Steam fittings, Model fixings, Castings sets, Copper boilers, Steel boilers and Drawings

www.maidstone-engineering.com

100mm cast iron. Grade 250

100mm cast iron. Grade 250

maccmodels.co.uk

Pardon our interruption...

 

[Susquatch]

@PeterT - when was your original post? Site was down just briefly and restored an hour ago.

 

[carrdo]

Hi Peter,

One UK site says all sold out and the other UK site says doesn't post to Canada.
I know you can source Meehanite in the UK but the shipping cost here is astronomical if and when it is available. I know Meehanite iron is available in Canada but just where...

 

[PeterT]

@PeterT - when was your original post? Site was down just briefly and restored an hour ago.

It was maybe 3:00-ish PM MST? No biggy, was just mentioning in case he got a different looking message I started.


@carrdo good luck, hope you find a supplier. BTW, just curious what is the specific application? I haven't seen too many hard chromed pistons in (I assume) might be a model engine?

 

[carrdo]

Hi Peter,

Yes, you are correct. It is for a 2.5cc model 2 stroke speed model engine which I started (from a casting kit) when I was sixteen. Craig Asher designed it in 1959 and in 1960/61 it won many domestic speed events. It was also entered into and did very well in international speed competitions for those years. This is just before schnuerle porting and tuned pipes on speed model engines were introduced.

I soon gave up as I just had a battered old Myford ML7 lathe at the time and not the experience/skill/tools/finances to get any further on any of the parts other than what is seen in the photo. It is even now an incredibly difficult build. It was reported to be able to turn up to 26K which was a fantastic RPM for the time.

 

[phaxtris]

Cast iron for a piston ??

Edit; i will add .... in an ice engine ?

 

[carrdo]

Yes, cast iron for the piston. But not just any cast iron. Craig Asher knew what he was doing. I have all of the the construction articles and there was a very good reason for using it in this case -because of the design. Using an aluminum (alloy) piston would not have resulted in a lighter piston because of the special design of the piston/liner. Any aluminum piston would have had to use a lot more metal than the Meehanite CI piston even though aluminum is much lighter than CI so there was no piston weight saving in this case by using aluminum. Also, this is a ringless piston so the piston/liner fit is an incredible tight tolerance which has to be maintained under all operating (extreme) thermal conditions and as a result material selection is crucial.

 

[phaxtris]

gotcha

just seemed odd, aluminum is the standard material for 30k rpm nitro engines, must be a different design

 

[PeterT]

Cool, I had a hunch. Before my time & not really my thing, but I recognize the name from some of the dark alleys I frequent LOL. On some of the model engineering forums (https://www.modelenginemaker.com/index.php specifically) I have seen bar stock reproduction builds of some of the classics. Whenever Meehanite comes up in discussion, its usually followed by what a bear it is to find anymore & that's from the UK side of pond. I've heard its a tradename for a specific process. I've also heard that one of the Durabar varietals is a 'decent' substitute, but that may have been related to liners and/or from a guy that had no other options. Hard chroming is another wrinkle. I didnt realize pistons were done, but these guys broke all the rules. And Durabar s not exactly hanging around the local MetalSupermarket LOL

Long shot, but maybe contact Adrian. I've heard he is tied into the parts & restoration crowd.

AdriansModelAeroEngines.com :: TECHNICAL TOPICS

He mentions Asher here

AdriansModelAeroEngines.com :: Speed Championship, 1960

I thought I saw something on ebay from a store like this like piston 'blanks', again for the restoration crowd. Nothing here, but sheesh some of the oldies fetch some coin

Items for sale by speed_demon_diesel | eBay

Shop eBay for great deals from speed_demon_diesel!

www.ebay.com

Good luck. Do you do your own hard chroming or outsource?

 

[carrdo]

Hi Peter,

No hard chroming facilities here. Will have to outsource and this will present a problem as I don't trust a regular chroming facility to successfully handle a job like this. The specs. say the piston is to be "flash chromed" 0.0003" total to at least 60 RC and then polished.

 

[Susquatch]

Always more than one way to skin a cat. I'd add a different perspective here

Back in my engine design days there was always some engineer with a great idea that required exotic materials to execute. After you asked them to pay for it out of their own pocket, the design often got more reasonable. It's easy for me to imagine an engine design parameter that would require meehanite pistons. Rather than start over and remove the constraint, you just spec meehanite and life goes on. It's not an ideal situation but it's what happens when you get locked into a given design and don't want to start over.

Small volume small engine design is a specialization that simply cannot support the thousands of iterations that a commercial design would undergo. So meehanite it is.

 

[PeterT]

I was trying to see what kind of applications Meehanite was used for with the thought that maybe you could find, oh I dunno, a big muther caterpillar crankshaft at a wrecker & corner the market for model engine supply Haha. Probably about the same odds as tripping on a gold ingot. Amazingly there are many Meehanite sub-varietals I wasn't aware of. Not that I knew much about it anyways.

https://meehanitemetal.com/wp-content/uploads/2016/06/MEEHANITE-HANDBOOK2.pdf

Re model engine hard chroming, apparently Jim was 'the guy' until he passed couple years back now. I'm pretty sure he did Nelson's & possibly Jetts liners. (I used to pylon race so I knew guys who knew guys...). My buddies got a shop tour of the skunkworks which made me insane with jealousy. This post was one of his last & shows some of the chroming specialization involved. Apparently even when the chrome goes down right, the real fun begins grinding & then the experts divide again on lapping.

.90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine

.90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine

www.modelenginemaker.com

Not directly related unless you hit a dead end and/or just enjoy the engine era.

An Italian (5cc) Beauty

An Italian (5cc) Beauty

www.modelenginemaker.com

My radial. The liners are class-40 gray iron, lapped to within 0.0001". Its 4-stroke so uses (commercial) rings. Which, I concluded is painfully more work. Making the CI rings isn't any more challenging than other bits, but I didn't have the proper heat treat oven gear to heat-set the rings at specific temp + soak period. But I will overcome that issue on the next build!

 

[Tom O]

I was trying to see what kind of applications Meehanite was used for with the thought that maybe you could find, oh I dunno, a big muther caterpillar crankshaft at a wrecker & corner the market for model engine supply Haha. Probably about the same odds as tripping on a gold ingot. Amazingly there are many Meehanite sub-varietals I wasn't aware of. Not that I knew much about it anyways.

https://meehanitemetal.com/wp-content/uploads/2016/06/MEEHANITE-HANDBOOK2.pdf

Re model engine hard chroming, apparently Jim was 'the guy' until he passed couple years back now. I'm pretty sure he did Nelson's & possibly Jetts liners. (I used to pylon race so I knew guys who knew guys...). My buddies got a shop tour of the skunkworks which made me insane with jealousy. This post was one of his last & shows some of the chroming specialization involved. Apparently even when the chrome goes down right, the real fun begins grinding & then the experts divide again on lapping.

.90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine

.90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine

www.modelenginemaker.com

Not directly related unless you hit a dead end and/or just enjoy the engine era.

An Italian (5cc) Beauty

An Italian (5cc) Beauty

www.modelenginemaker.com

My radial. The liners are class-40 gray iron, lapped to within 0.0001". Its 4-stroke so uses (commercial) rings. Which, I concluded is painfully more work. Making the CI rings isn't any more challenging than other bits, but I didn't have the proper heat treat oven gear to heat-set the rings at specific temp + soak period. But I will overcome that issue on the next build!

I Every video I saw just used a torch to set the gap.

 

[PeterT]

Tom, if you ever want to start a 100-post sh*tstorm, just mention the words 'piston rings' on a model engineering forum HaHa. Yes I too have seen the 'heat till they drop off the bar' method & even substantiated that (some) engines even ran well. I even tried a few rings myself but results were so-so comparing them alongside commercial rings.

There is a well established methodology documented in Strictly IC magazine by a pretty bright guy called Trimble who basically reverse engineered rings from base principles. The optimal ring dimensions are determined by being within 4 constraint curves & he discusses these in detail. Once the rings are sized according to the method, they are cleaved, set on a specific (calculated) dowel spreader pin on the neutral axis & 'heat set'. If you follow the recipe they provide uniform radial force to the cylinder wall which is exactly what you want. The chart (my Excel version of his formulas) shows the example constraint curves. A big consideration is actually being able to spread them sufficiently over the piston crown without yielding them. These are pretty teeny. For example a 1.0" bore results in a ring section 0.043" wide radially & 0.023" axially. If you deviate from the recipe it potentially adversely affects one of the other important factors. Anyway, he did the heavy lifting so that the resultant math is trivial for anyone to calculate dimension just knowing the bore.

But specific to temperature, he was also adamant about annealing within a very specific range & soak. I have overlaid this on Durabar chart which provides some insight as to what their heat treat temperatures correspond to so I think it goes around. I compared his calculation & resultant un-spring open gap to all the commercial model rings I could get my hands on & they checked out perfectly. I think others even compared to some auto rings & it worked there too (probably what Trimble referenced if I had to guess).

So in my own opinion, I think this might be doable with a torch until the ring drops off a spreader bar, but probably hit & miss results. At least that was my experience. Even with super careful uniform torch movement, the buggers are so small you have little idea of true temperature. If you happen to dwell the torch just a teeny bit more on the opposing side of bar, yes it falls off & yet you probably had inadequate heat affect on the remainder of the ring. So far this pertains to the heating up aspect only. The chart also shows that the chill rate (quench) dictates resultant annealing mode vs hardening mode at certain temp ranges. You don't want hard. A gradual (oven) cool down is preferred & was also prescribed. So IMO putting a stack of rings in an oven with a reliable temp setting would be preferable. Set the temp & time & remove when the cookies when baked to perfection. Unfortunately HT ovens are kind of spendy. Not sure I will ever buy one but I can probably hunt down a blade maker guy with the right equipment.

Apologies for the cast iron ring tangent!

https://www.dura-bar.com/getmedia/5cf7c409-fdce-4861-b2b7-770c942368b1/heat-treat-guide-0719.pdf

 

[Mcgyver]

Terra Nova in Miss is the local durabar distributor but I bet they'll be expensive and may have minimum orders. Been in the back, they have a massive amount of cast iron, some sections several feet by several feet in profile, neat place. We need a CHMW friend there who'll let us pick from the scrap bin lol. I'd be thinking McMaster Carr would be lower cost.

Try searching for flash chroming, afaik a different process than hard chroming (but both are hard obviously). I've had several parts hard chromed (specifically TS quills for machine being reconditioned) and they have instructed me to grind some off the OD and then they'll add 15-20 (rrc) thou as you don't want it thin else it will flake off. When you get the part back its not that good a finish and then needs grinding. This is a standard repair technique so its possible/probably that shops set up for it don't also do flash chroming.

Here's one source. It might be really expensive to get a model piston done, curious to hear what you discover on pricing.

Flash Chrome

Flash chrome plating applies a thin layer of chrome and is suitable for applications needing light wear & corrosion protection. Learn more.

www.uschrome.com

On the iron, as I understand it, Meehanite is a brand that licences out the process but the material itself comes in several grades. If you need grey (flaky) or ductile (nodular), would it matter whether its from Meehanite or Durabar? I bet continuous cast iron manufacturing and metallurgy has come a ways since the time when the designer spec'd the metal. i.e. if he was located in NA in 2024 what would he select?

If it has to be some grade of Meehanite for some reason, get these guys to cast you a piece. Hey, you asked where to buy, not where to buy for less than an arm and leg

Casting Metals and Alloys - Castings for Industry - Metal Casting Sourcing

Casting Metals and Alloys. Ferrous Metals are steel or cast iron. Nonferrous Alloys depends on their base elements with one metal and other element(s).

www.castingsforindustry.com

 

[carrdo]

Hi All,

A very interesting discussion so far - keep it going.

Well, I am not exactly up the proverbially sh-ts creek without a paddle as I do have one last piece of GA-50 Meehanite. It was given to me decades ago by Harry Hawkins, a past President of TSME. I don't know where he got it from but Harry did me so many favours over the years. It is the last of the Mohicans so to speak (to be politically incorrect nowadays) but whatever.

I did contact the Meehanite Institute in the US and they indicted there is no Licensee or supplier in Canada for Meehanite. Interesting enough, many decades ago when I was a pimply teenager, John T. Hepburn Ltd. (a heavy machinery constructor/machine shop for the mining industry. They were originally located on Dupont Street and Geary Avenue here in Toronto near to where my parents lived at the time) did carry bars of Meehanite (now that is going back more than half a century). Even then it was an atrocious price and having no $$, they wanted over $50. for a few bars of it - a King's ransom.

 

[PeterT]

Personally I think you would be better served to get inside 'the Holy Brethren' circle of competition model engine builders still around & ask them about what you are embarking on. Several of these guys grew up & competed with one another in CL speed events before making a semi-business out of it & probably know exactly what was done & why. But it a diminishing population. Sadly, these guys are not getting younger & most competitions are in a death spiral. Their best days are behind them competing with video games & RTF import models with a 'come home' button. These guys make majority of parts themselves but to best of my knowledge, farm out chroming as a specialty service. One can imagine it must be niche even for them. Unfortunately liners are a different alloy & plating process than CI so doubtful you could even piggyback your part to theirs.

You could try reaching out to this guy. He is very knowledgeable & has been around the CL competition block for decades. I still remember early 80's he showed me me some single blade counterweight carbon fiber props originating from eastern block Europe before the wall came down. I think they were spinning 40K back then. First time I saw CF anything for that matter. The gig was you brought over a suitcase of blue jeans to a competition event & came home with good sh*t. I heard some of these guys worked in <ahem> 'specialty trades' so had access to things or things came home in lunch buckets. But I digress haha.

Paul Gibeault's guide to mixing your own fuel

One of the euro engine gurus. Very knowledgeable & down to earth. I think he had a CL pedigree before embarking into RC speed.

homepage

Another option if this doesn't pan out is a modernized version & you will have to make personal peace for your sins. There are apparently quite a few shops that do Nikasil ?sp? resurfacing for I'm guessing bike engines & whatnot. I have no idea if it would be comparable or even feasible given your unique running conditions & maybe different base metal prerequisites too. I think they hone the resultant bores (like a Sunnen machine), so suspect you would need the male equivalent of that. Which may be different than what is used on chrome. Good luck & keep us posted!