Repairing a high quality model marine engine

Gallery, Projects and General > Project Logs

<< < (13/24) > >>

bogstandard:
This was supposed to be the last post for this topic, but due to unforseen circumstances, it is the penultimate one.

As I said on the last post, I am just making a few extras for the customer to make his engine a little easier to operate and a lot nicer on the eye.

This is one he didn't ask for, but I recognised a problem. To empty his displacement lubricator, he would have to take the bottom plug all the way out to get rid of the water in there. This will also drop any oil that is left, and has to wait until there is no or very little pressure in the line.
I knocked up a new plug that when it is undone by 1 full turn, any water is dropped out of the bottom of the plug, and as soon as oil is noticed, it can easily be closed off. This will also work with pressure in the line, using it to force the water out.

You can see how it just screws into the normal place on the bottom of the displacement lubricator.

I had been asked to fit small acorn (domed) nuts onto the cylinder covers. But as you can see, the original one on the right just didn't have enough 'land' to fit the nuts on, as they would have hung over the edge of the cover. So a new slightly larger pair of covers were made, the beginnings can be seen on the left. Also what can be seen is a piece of hex bar to make the nuts out of.

A new pair of covers, they still need to be drilled and have three flats put on them so that they don't look too large for the top when they are fitted. Also, studs have to be fitted like they were on the steam chest covers.

Now a quicky lesson on how to make acorn nuts.
Hex bar was cut and trimmed down to 4.5mm long.

For fast precision drilling, I mounted the tapping drill into the tailstock chuck and fitted a piece of tube over the drill. Then using a digivern, I set 4mm sticking out of the end of the tube. So no matter how far the bit is sticking out of the chuck, the tube will bottom and I will have holes drilled to 4mm depth. The bits were centre drilled before drilling, and they were tapped and countersunk slightly afterwards.

This is what I ended up with.

The next job was to grind up a small profile tool that cut from the tip of the work towards the chuck, rather than a side plunge cut, which meant I could use my saddle stop to end the cut and I wouldn't need to touch the cross feed after it was set to depth.

A bit of brass bar was mounted up, face off and tapped to accept a little piece of 8BA threaded rod.

So all that needed to be done is, put a nut onto the threaded rod, and feed the saddle until it reached the stop. Nut profiled, next one.

So this is how many I got made (just over half of what is required) before my lathe motor decided it didn't want to work properly any more. It would not ramp up by itself, just turning over slowly until I spun the chuck up by hand, then it would climb up to full speed. A quick call to Chester UK verified that the caps had gone in the motor, and a brand new motor will be with me first thing in the morning. Can't be fairer than that. Mate coming around tomorrow to help swing the lathe out and swap over the motor. Then I can get these little buggers finished off.

So the steam chest covers will get these little beasties, and the cylinder covers as well (when the nuts are finished).

This is a little bit I have done previously, put a kink in the operating handle to get me a bit more meat onto the back rod. The collar on the handle was drilled 8BA clearance and the rod was tapped thru 8BA. This will allow the handle to be more easily removed than if it was pinned as shown on the plans. Also a set of correct pitch servo holes were drilled to allow radio operation of the handle.

This would have been on it's way to the customer today if the problem with the lathe hadn't happened, so I have contacted him and apologised for the delay. For his understanding, I will make him something special for this engine while I am waiting for the motor.

The next post will definitely be the last.

Bewildered Bogs.

sbwhart:
John

Do you need any help with that motor tomorrow ?.

Stew

bogstandard:
Thanks very much for the offer Stew, but my mate has got it all in hand, I will just let him do it all.

I will sit on one of my tall chairs and shout him instructions, while keeping out of spanner range. :lol:

But if you could call around to pick up that sample I was talking to you about, that would be great.

John

Divided he ad:
Bugger about the lathe John!!! :bugeye:

I do like the drill stop.... Seems so easy once you've seen it done :doh:

I'm not going to fall into the obvious trap..... But, I do like your acorns! And your method of preparing them :ddb:

Hope all the motor repair goes to plan! :zap:

Ralph.

TFL45:
Hi John,

Small world! The owner of the engine you're working on picked me :scratch: to give him a few tips as he assembles his Graham Industries TVR1A. He steered me here when I commented on the fine boat in his video on YouTube. If I'd known that he had access to your expertise, I would have headed for the exit - fortunately, I didn't lead him too far astray.

Glad to hear that you're back in form and as usual, another great series of posts. :bow:

Floyd

Navigation

 Message Index

Go to full version