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Hi Patrick - a wonderful build - congratulations. Why not make a twin HB - will try to help you with plans if you wanted to ... kind regards ... Ed

I used to machine the whole bar to make the bigend (crankpin) on the end of a conrod a long and horrible job - these days I drill a hole to depth and the humble hacksaw does most of the rest of the work and the lathe says thankyou.

Hi Gerard, sure sorry to hear about your fall - we don't bounce as well as we did when we were younger .. Great news about the Buddy ... perseverance pays off, and the fit is not easy to achieve. Well done Gerard .. and thanks for letting those interested in this thread know ... cheers ...

Next installment - machining the venturi hole. Simple process, setup in the vice and ensure chocked so it can't move when jaws done up around the nose extension. Drill the 5.5 mm hole and lightly face off each side flat. Make the rear cover with an extension and screw in then holding that in the...

So the next step was to deck the top of the crankcase, bore the cylinder well and drill and tap the 4 x 3 mm hold down holes. The deck was machined flat as per above dimensions which in fact was "cleaned" by just 10 thou, so the casting had just enough meat to allow spec to be maintained. I had...

The next step is to create the cylinder aperture and hold down bolt holes. I actually modified my vice so the I can clamp things down that are within the jaws, to do this element of the build. You can see how this works in the 3rd photo. I needed to know how much to take of the "deck" as a...

Now the spigot at the front has been machined, time to turn it around and complete the tunnel part of the case. I always have a second thought before taking something out of the chuck, once disturbed it always runs the risk of a bit of run-out. But instead of removing from the chuck, it was...

This is truing up in the lathe and taking first cuts. Using the rear boss l only had to move it once and it came up within 5 thous of run-out for the front. The first cut was 5 thou and it cleaned up all except adjacent to the join line, another 4 thous cut and that dis-appeared. This shows the...

This is the casting second time around and the one for the build as received from CAMCAST.

The original Holly Buddy is a relatively easy build made from round and square bar stock. It is a chunky engine of 2.5 cc capacity and quite a few have been made now, and it was the subject of an article by fellow Australian Maris Dislers which was written up in the 2019 issue of AeroModeller...

Guys, Thanks for staying with me on this - will now start a new thread for the Holly Buddy Mk2 build to help any future builders with my experience making it. cheers ... Ed

Hi guys, An update on the casting. The initial one took quite a while to have done as the heat treatment only gets done once every three weeks or so - then when l got it, it wasn't very smooth l think because some of the casting sand was still attached to the pattern, so when the casting was...

There is a source here in Sydney - best send me an email at address 3rd last post previous page this thread ...

Still nothing there ...

Dean, didn't get an email from you yet ??

Dropped the pattern off to Camcast this morning - looks like $60 AU including heat treatment each .... which is not much more than they charged for the castings l had done about 5 years ago Can you guys that have indicated you want one or more please email me ... edholly at optusnet dot com...

Hi Tomcat, I didn't publish the plans as there is a problem with stabilizing the centre interlink's housing in the case - l know how to solve it but haven't got around to it yet .... maybe one day - a few projects before hand though ... thanks for the query .. regards ... Ed

For those interested in the pattern - it is made from Aluminium and the various bits were glued together and a bit of filler used to fillet various bits - then a coat of silver paint. Took about 10 hours to make maybe a bit more - but it will cut down the build time considerably, especialy for...

Been a while since l posted here - the Holly Buddy continues to run well and I have decided to try to make it a more normal looking engine with a rounded crankcase. To that end ... here is the pattern to have some Holly Buddy crankcases cast by a local non-ferrous foundry. They have done work...

Bought this recently - it is a really beautifully built engine - way above amateur status. It is a Spark Ignition motor, however if and when l get it going l will run it as a glow motor. It has evidence of being run quite a bit - as an air-cooled marine engine. There was quite a bit of old hard...