Author Archives: Sophie Whiptank - aka Bart

About Sophie Whiptank - aka Bart

I'm just a bloke doing some stuff, the more interesting bits I post on my blog. Scroll down far enough and you'll see me riding from Melbourne Australia to Birmingham, England in 2014. But now I'm working on another project, a single cylinder motorbike engine at 2750cc!

Caught on camera!


I hid quietly in the back of the shed, waiting patiently. After what seemed like hours, one came cautiously around the door. Another following meekly behind. Eventually they relaxed enough to start work, when I was able to take a quick photo on my phone!

Probably a world first, photographic evidence of the existence of shed faries! Here, they are drilling a set of engine cases to be reamed later, to accept silver steel dowels for accurate location. I managed to leave undetected and lived to tell the tale.

Preparations for Ron.


(Later Ron) 🙂

The shed fairies have been busy again, working on making the Denbeigh mill a better machine. Bob is certainly very through! The vertical head has been stripped and greased, then re-assembled with a new drawbar assembly. The head has been set parallel to the table and the machine run for 15 minutes to make sure nothing gets too hot or stiff.

The drawbars took some work, with the rear of the machine sawn off by 2 inches to allow the shorter ones to be fitted and tightened. Spacers and locators made and in general, the machine is now much better and ready for use. We’re waiting for the steel plate to arrive, so we can bolt the enormous cases to various machines.

I love seeing this kind of work. Some of those items might not be required for 10 or 20 years, but one day in the future that will might save a load of time.

Vertical head, sideways on?


The original idea of boring the cases would have worked, but using the boring head in that position would have meant we couldn’t see inside the bore. Blind operations are ok, but I prefer to be able to see what’s going on. It’s fair to say that your ears tell you a lot, but even so it’s good to have eyes on what you’re doing!

We looked at making an adapter plate to swing a vertical head through 90 degrees. (Sideways, so to speak!). When we dug out an old vertical head from under the bench, it turns out it’s adjustable anyway 😁 So with a bit of fiddling to get it parallel to the table, the boring operation is all worked out.

Sizing up the Denbigh


Here’s one half of the cases plonked onto the table of the Denbigh mill. You can see the flailing belts which have to be hand pulled to help start the motor to the rear of the machine!

The boring head in the photo will automatically expand to perform a facing operation. It was second hand and hasn’t been used yet, plenty of old stuff that ‘might come in useful one day’ is being pressed into service – and it’s good to see. Shed recycling to save the planet 💪

The second set is being drilled and the second timing case milled. Once those jobs are complete, we can look closer at fitting locating dowels. Finally, we will come back to the Denbigh….

Together forever!


Well not yet, but one set of cases has been drilled and assembled by the shed faires. They were busy while I was on holiday!

The machine in the background is the Denbigh Mill. It has the capacity to machine the bore and face off the throat, which even the Bridgeport won’t manage.

It’s an old machine and in breach of just about every health and safety regulation ever written! (So I tend not to use it). But with common sense and due care ut should do a good job for us.

In parallel I’ve been facing the timing cover, which is quite tricky to mount – but one I have a flat face the rest should be easier. Making 2 complete sets of cases isn’t much extra work, and a spare set will definitely be worth having.

(They’ll make a good ornament/doorstop at least!).

First cut of the cases


The drive side case was first up for fly cutting the mating surface. Bob mounted it to the table and did the faffing about getting it level, but in fairness the casting was pretty straight. I did a dry run of the tool path and when that was complete there was no delaying it. Time for the first cut!

The mighty Bridgeport performed admirably and 20 thou cuts were a breeze. I showed Bob how to start the program and after a couple of goes he was away. We had to take about a quarter off the height, which didn’t take too long at all.

Loads of man glitter kicking around now, so I need to be careful not to get it round the house. Swarf gets everywhere doesn’t it??

On the case!


Weighing in at 26.7kg, one full set of cast engine cases. I weighed them as I wanted to know how much metal gets removed when I machine them. There’s a generous allowance for machining and they’re quite heavy, so hopefully I’ll get to under 25kg.

I had a couple of sets cast and heat treated, so I’ll machine a spare set. The spare can be used for a mockup engine with a barrel for dimensioning the frame. But that’s a way off as there’s plenty of machining to be done. Bob and I will work together on the Bridgeport.

Here we go!