Patterns Mk. I


It’s been a while since I updated the blog, with the Christmas and New Year slow down. I also too a break while watching my friends Chip and Ken ride from Virginia to the southern tip of Chile on their excellent blog. I wanted to join them but couldn’t get the time away from work and home, but I digress. Back to business!

I had a quote to 3D print a pattern in plastic at £240 + VAT. Quite reasonable I thought, except that if the pattern was wrong it would need to be altered and re-printed. Right first time would save around £180 on the quote for making a traditional pattern in wood. Right second time would cost and extra £60, and after that it gets expensive. Trouble is I’m not a pattern maker so a lot of it is study from the Internet and, er, guesswork!

But wait, weren’t we going to 3D print the cases in stainless steel? Well yes, until I have a quote at over £5000! Sod that! I won’t name the company as they were very helpful to be fair, and I don’t think that’s necessarily a bad price, it’s just not the right process for an object of this size – or my budget for that matter. So it’s back to pattern making and casting in LM25 Aluminium Alloy, with the dilemma of printing vs paying a traditional pattern maker. I mentioned this to Nick, who promptly said…

"Oh, I can make one in wood. Just not in metal". Really? Oh ok, well that makes perfect sense. I’ll ask my drawing office (Gary at work) to do me a favour and modify the drawing to what I think the pattern should look like. A cup of tea with Bob and quick chat later, I had a set of marked up printouts ready to forget to take to work for a few weeks. I safely delivered them today and wait patiently for the amended CAD files.

Onward and Upward! Oh and Happy New Year!!

P.S. In case you were wondering, Chip and Ken they made it safely back home. You can read more about it here ->

Big wheels keep on turning.


With work on the conrod finished for now, attention turns to the flywheels. The slices of big bar fit into the 4 jaw chuck on Bob’s lathe, which is handling the job nicely so far. Getting the tough outer ‘crust’ off the steel is hard going, light cuts are needed and plenty of cutting oil.

It might not be too healthy, but it smells great!

There’s a fair weight to each wheel so it’ll be a weighty engine, maybe a 2 man lift. Then again so is a GPZ900 so I’m not too concerned.

We can’t swing the conrod though, even on the big lathe. It’s 14 Inches and the lathe will spin 12, so some thinking is required to finish the eyes.

Anyway, small progress is still progress:-)

Birthday deadline….


Now that’s a conrod! Bob took the other side off and voila, the mighty conrod is out! I held it in my hand to give some sense of scale in the photo, I do hope it’s big enough 😉

It’s quite fitting that the conrod emerges today as it’s my birthday. I set a deadline of hearing the engine running by my 50th birthday, so we’ve 3 years to get the whole shebang sorted. Actually I’d like to be riding the bike for my 50th, but I’ll settle for a running engine.

I’m very pleased with the progress so far, and have high hopes for the 3d printed cases – provided that the price is right. Time will tell.

Flywheels, crankpins, crankshafts and sleeve drive.


Can you see them? The steel has arrived and £ for lb it’s not bad value. Good job we’re not making it in Gold!!

It doesn’t take much imagination to see the flywheels, though a lot of work needs to happen before we get the finished articles. Fred might be coming up this week and joining the production team.

Also on the team, Gary has been busy on CAD and we have the side cover in a 3d drawing. I’m getting quotes to 3d print one as a full size model in plastic, but also a price for 316 stainless.

Stainless engine cases, that’d be a first!

Little end


The radii around each end is complete now, after a week or so off to cover work and funerals. The big end is also complete now and one side is removed. Now that’s real progress!

The other side might be off today so we’ll have a complete rod bar finishing work. It’s a great effort from Bob but at the same time an eye opener to how much spare time I don’t have.

I need to retire myself 🙂

Taking shape


A great weekend with new and old friends round, getting the full shed tour. Nick seems keen to take on the diesel 2-stroke 500cc and I’m right with him. Maybe that should be the testbed for his infinitely variable transmission idea? Further discussion is required!

The conrod is starting to take shape now, you can definitely work out which is the big end! I have a shopping list for EN25T steel bar to make the flywheels and crankshafts from, which I’ll sort when I’m back from London. Graham should be moving the Hercules at the Airfield to a hangar in the next week or so, where it’ll be easier to work on.

Progress all round!!