Swifty's build of Rupnow engine.

[Swifty]

Hi everyone, have started building Brian's engine, the only minor changes that I am making is to use metric fasteners, bearings and gears. I will be cutting both the spur gears and mitre gears myself.
I had a piece of material that I could make the head out of, so I made that first. I picked up some more aluminium offcuts a couple of days ago, and some bearings yesterday, so this morning I cut up the plates to enable me to start machining. I don't have a bandsaw yet, so using a combination of a slitting saw in the mill and a 120mm dia circular saw fitted with a blade for aluminium, I managed to prepare everything.


Now, back to the workshop.

Paul.

 

[canadianhorsepower]

hey welcome to this build
so far so good

 

[Swifty]

Managed to get a few hours in today, machined plates to size, drilled, tapped and reamed all the necessary holes in the base and side plates. Would have got more done, but my son dropped in and we went out for a few hours to do some errands and have lunch together.

Next I will mill the steps in the side plates, make the bearing caps, then bore out for the bearings.


Paul.

 

[Swifty]

Hi Luc, thanks for the welcome to the build. I cannot work on the engine every day, but will do my best.

Paul.

 

[Brian Rupnow]

Swifty--Great Progress!!! I am pleased to see another build of this neat engine. I hope you have fun, and come up with a good runner. ---Brian

 

[Swifty]

Managed to get a bit more work done on the engine. Decided to take a different approach on the bearing caps.

Paul.

 

[Cogsy]

Looking good so far. Wish I was that far along with mine.

 

[Swifty]

Don't worry Cogsy, you have your flywheels done, I haven't started to think about them yet.

Paul.

 

[Brian Rupnow]

Artistic license is encouraged. It looks great!!!---Brian

 

[Canman]

That's some really neat work there. Your flying along. Welcome to the build by the way.

James

 

[Swifty]

Cogsy and Canman, don't get put off if I seem to be romping ahead, I don't have a lot of time to work on it, but when I do I can move fairly fast. After all I did work as a toolmaker for over 35 years.

When I'm working on one part, I'm already thinking how I will do the next one so I can go into that setup straight away.

Paul.

 

[Swifty]

Been thinking lately about what I am going to use for the flywheels, didn't have any large enough solid bar or plate, then there it was staring me in the face. I have this large piece of hollow bronze bar that has been sitting around for years, so why not use that. I plan to use a steel centre piece and shrink the outer rim on. The next problem was that the bar is 4 1/2" OD x 2" ID, the only metal saw I have is a hand hacksaw, so decided to part it off in the lathe nearly all the way through and hand hacksaw the remainder.
My parting tool would easily part off all the way, but did not relish the thought of pieces flying all over the shop. So I set it up in the 4 jaw and used a block against the tailstock end to make sure it will hold there, set the speed at 70 RPM and went to work. Once I had a full cut going, I just held a steady pressure on the handwheel and one foot on the brake lever just in case. Stopped short of the bore, as it wasn't running true and I didn't want to break partly through, then hacksawed the rest.



And now I have 2 blanks for the flywheel.



Paul.

 

[Brian Rupnow]

Those flywheels will be real beauties with a steel or aluminum center.--Brian

 

[Swifty]

Machined up the flywheel outer rims this morning, shame that I can't do anything with the bronze swarf left over. Off tomorrow to get some material for the inner part of the flywheel and also some 10mm dia. rod for the axle.



Paul.

 

[Swifty]

Decided to do a bit more on the flywheels, I was prompted to do this by my wife saying she was going to put the oven on tonight for dinner, so there was I thinking the oven would be a good way to heat up the bronze for a shrink fit on the inner. I had a piece of hot rolled mild steel that I wasn't really keen on using as it can be a pain sometimes to machine and especially to part off, but despite this I got busy turning up the two inners.

Turned out not too bad to machine, but a pain to part off. I had to part off from the 51mm OD to the 10mmID, doesn't seem much, just 20.5mm depth of cut. Well all my fears were realised, it was a pain to part off, chattered like crazy, all sorts of weird noises, and I can't recall seeing a HSS parting tool flex so much without breaking.

Despite all this, the parts came out fine. I made them about 0.010mm interference fit in the bores of the bronze. Once the bronze had been in the oven for about 30 min, I grabbed each piece with the oven mitt, carried it to the garage and placed it over the centre pieces, they slipped on fine. Just have to give them a bit of a polish to remove the discolouration from heating up.



Paul.

 

[Brian Rupnow]

Nice work. I have been advised to try that same type of shrink fit on the two part flywheels I make, but I've always been afraid to try it. I always default to a sliding fit and green Loctite.---Brian

 

[Path]

.....

Despite all this, the parts came out fine.

......
Paul.

Now that is an understatement if I have ever heard of one ...
those came absolutely beautiful! Thm:

Thanks for posting your progress .. following closely.

Pat H.

 

[Swifty]

The bores on the bronze probably expanded about 0.10mm, I had no trouble dropping the rims onto the hubs. As there is no force at all on the rims I only allowed 0.010mm interference. Had tried shrink fitting years ago, but probably allowed too much for interference as the rings grabbed as soon as they were part way on. Ended up having to machine the part off and starting again.

Paul.

 

[Swifty]

Hi Pat, glad to have you along following my progress. I checked out your website and your larger lathe and mill are around the size I have as well.

Paul.

 

[Swifty]

Not a lot done today, picked up some silver steel to use for the axle, 75min round trip. Drilled the holes in the flywheels, still needs deburing and cleaning up.

14 month old grandson over tomorrow, so not much work on the engine then either.




Paul.