Author Topic: The Oliver Tiger Mk III - a 5cc Version  (Read 13446 times)

Online steamer

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #45 on: February 17, 2019, 09:52:10 PM »
Nicely done Ramon!    Nice bit of carving there.
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Online b.lindsey

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #46 on: February 17, 2019, 10:15:08 PM »
Beautiful work Ramon. Those curved surfaces look great. Nice save on the bearing depth issue too.

Bill

Offline Admiral_dk

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #47 on: February 17, 2019, 10:33:54 PM »
Great progress Ramon - I really admire your patience and the result of fettling those "curves"  :praise2:

I have previously started on restoring my vintage Viking here :
http://www.modelenginemaker.com/index.php/topic,6296.0.html
But I broke my own rule about NOT modifying any original parts  :-[
So I decided not to continue down that road before I had some more time on an engine where another "cockup" wouldn't matter as much, and in the end this will be a kind of continuing the saga.

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #48 on: February 18, 2019, 01:19:40 PM »
Hi Dave , Bill and Per - Thanks for looking in and taking the time to comment - comments are always appreciated  :)

Shows how age affects you Per I had forgotten about your posting (and my replying :-[) on your engine  ::). I must say it's quite an imposing design so do hope you are able to pursue it much further.

I received an email from Neil this morning and as the context of it was new to me and certainly relevant to this kind of  build I thought it worth sharing - hope you won't mind Neil  :)

Ramon,
Years ago it was often required to rebore the front end of the Rossi 15
engines. The thinnest sleeve I made that was successful was  0.5mm wall.
Although mostly I made them 0.75mm wall. Some needed a sleeve like a top
hat. I always bored to final diameter and depth after the sleeve was
pressed in.  Funny enough,  for me the best way to assemble  the sleeve 
was making it a press fit and using castor oil to allow the 2 parts to
assemble. These did stay in place, even when changing the front bearing.
A common way of holding the case for the rebore was to turn a free
cutting steel mandrel that seated on the rear bearing end seat , and the
bearing diameter. It also was snug on the area of the backplate
diameter. I made these mandrels 0.01 to 0.02mm bigger than the measured
case bearing diameter, and 0.01mm bigger than the backplate seating
diameter. Heat the case until the castor oil smokes and it slips on or
off real easy.
I found that if I identify the jaws of the 4 jaw chuck with the mandrel
being turned, that I can get the mandrel to very easily be repeatably
set up again.
Great work on the engines and the cases. I like the way you did the
staircase thing to get the blend. It is neat how handy a marker pen
really can be, and ball nose and hog nose cutters.
Keep up the great work and the awesome pictures and the informative
write up.
Neil


The idea of using the castor oil to not only ease the fit of a press fit but to indicate the temperature is new one on me and sounds like a very good idea  :ThumbsUp:

I'm not too sure about holding on a mandrel just on the bearing depth but accept your experience in that it works in practice. I've always made expanding mandrels to do this kind of operation locating, usually, on the inner bearing housing and extending into and expanding inside the crankshaft hole for maximum grip and rigidity. As ever though, there's always more than one way to go about a job and this certainly gives credence to that thought . Thanks for that input Neil - it's a very useful tip indeed :ThumbsUp:

Comments are always welcome guys - I know some prefer not to have the thread interrupted but as long as they are relevant I always think they add to a thread - I'll leave that up to you but it's always nice to see that someone has taken the time to comment.

I made a tentative start on the top this morning - snuck away for five minutes from the shared domestic duties day  ;) Hope to make more progress this afternoon though :)

Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #49 on: February 19, 2019, 06:56:11 PM »
Hi Guys

Thought you might like to see how that top area is panning out - pleased to say, so far so good  :)

Taking one case at a time the side profiles were done first before resetting to do the corner pillars


All cutting was done using this 1/8 ball nose slot drill and plunge cutting. Tedious at a degree or two at a time but much better than the risk of that slender cutter plucking and pulling itself into the work. Depth was to the highest transition point then the fillets in the corners were gingerly milled out by eye


Then the fun begins, trying to 'dremel' out the profile by hand. This looks much worse than it is and is the initial approach. Constantly inking up helps see where you are


This is the other side after the initial shaping - it still has some work to do on it before final 'sanding as mentioned before. Still not pretty but beginning to look like it should


I have two done to this stage, one more to do before tackling that area around the venturi - still have no plan for that as yet  ::).

As usual - hope that's of interest

Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Online sco

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #50 on: February 19, 2019, 08:47:57 PM »
Ramon,

Still following on and impressed how you cut the profile by hand with the 'Dremel' - what type of bit are you using?

Simon.
Ars longa, vita brevis.

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #51 on: February 20, 2019, 01:56:59 PM »
Ken -

Yes I think I am aware of the type you describe as have certainly machined similar but have not known the actual specification. I've always thought of it as like machining cast ali but the brass analogy fits just as well.

The material being used is very easy to machine - I assume it is HE30 as I was given it as such and though from a reliable source can't be 100% certain. I don't use coolant other than applied by brush but all machining on these cases so far has been carried out dry. I have not experienced any build up on tools even when roughing the blocks down. All tooling is HSS save any home made cutters.

I enjoy the challenge of machining from solid - I did consider some time back whether to go down the casting route but decided that the outlay to do so would far exceed the amount of use it would get. The nice thing about barstock is you have built in perfect datums at all stages ;)

I will try to source some 2011T3 and see if it matches what I think I've used before. If it is I have a very nice big chunk of it under the bench.

Simon - they are 3mm diameter, shaft and head, cheap carbide rotary burrs bought off Ebay. Twenty different shapes for around a tenner. So far they've more than lived up to requirements but remember its usually only on ali

Tug
« Last Edit: February 20, 2019, 02:00:40 PM by Ramon »
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Online Jo

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #52 on: February 20, 2019, 08:31:52 PM »
That got someone's interest Ken he had to go and check his set of Majesco 45 castings  ::)

Jo
Usus est optimum magister

Offline Jasonb

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #53 on: February 21, 2019, 07:31:02 AM »
Machining from solid may be fun but it is not without it's compromises. For instance, and I know this is nit-picking, but with the exception of the mk 2 Tiger and one version of the cub, Olivers do not have an underside of the case which is a semi-cylindrical.

Ken, if you have a better look at Ramons drawings on the first page of this thread you will clearly see that he does not have a simple semi-cylinder, it tapers off towards the rear.

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #54 on: February 21, 2019, 08:34:22 AM »
Ken – you are correct, the Mk 3 does have this strange form below the engine lugs and an attempt to replicate this has been made.

Jason’s keen eye is on the ball as usual and the cases have been machined with this odd shaped area though perhaps not quite as prominently as the original. Though not shown in the pics I did this by resetting the tilting table at two separate angles and re-machined the rear portion – the transition points then ‘dremeled’ to give the curvature. As said, not exactly to the original form but close enough. I have now finished the top areas so will take a few pics to show this.

Though I do attempt to get these 5cc versions as close to the original shape as possible there are points where small compromises have to made - the reverse draft angles on the Eta cases is an example - but the overall effect is there - hopefully.

BTW I don’t see this as ‘nitpicking’ – as said previously, any comment, providing it’s relevant to the build, is always welcome – it’s input like this that makes posting worthwhile.

Norman’s Majesco is just that – majestic. A superb result. Has he done any more in similar fashion? (Edit- Do you know how he did that 'M' Logo on the transfer cover - very neat indeed)

Tug

"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Roger B

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #55 on: February 21, 2019, 11:08:37 AM »
Is there an expected benefit from the shape of the Majesco exhaust, does it match the ports?  :headscratch:  Looking at the rest of the workmanship it must have been designed like that.
Best regards

Roger

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #56 on: February 22, 2019, 09:15:07 AM »
Morning guys

Thanks for that Ken - he certainly made a convincing job of it. I've yet to do a sparkie - I have one near complete though and did intend at some stage to do a Hallam 9 from solid - the main block is prepped but it got overtook by diesels.

Simon - here's a pic of the rotary bits mentioned. The ones laying in the front are those used and include a discarded dental burr cadged from the dentist. Run at top speed on the power tool (an alleged 20,000rpm) they work very well  to take minuscule amounts off.


Ken - this shows the attempt to contour the lower case - not quite as pronounced as the original but enough to convey the impression



Made a start yesterday on the final stage on the venturi area. First op was to reduce the width leaving sufficient on for final machining.


Some of the surplus was just done by eye and plunge milling. Looks really ugly at this stage - you just have to keep telling yourself it will get better  ::)


The top front area was done by stepping over again


Ready for more fettling


Still a lot of work to do to finish this but the shape is there


Ready for the final op to define that venturi section


Each op is done on each case rather than repeating a series of ops, that way tabs can be kept on each step. The case with the red on it is the trial one to check if things will pan out - so far so good.

That's it for today

Back in due course - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline tangler

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #57 on: February 22, 2019, 10:14:20 AM »
Tug,

That's terrific.  I love watching this stuff.

Looking forward to seeing the finished items in the autumn.

Cheers,

Rod

Offline Mikesplanes

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #58 on: February 23, 2019, 09:28:43 AM »
Hi Tug,
I am new on here.
do you keep a log of how much time it has taken?

Mike

Online b.lindsey

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #59 on: February 23, 2019, 12:56:51 PM »
Some really impressive fettling there Tug!! Thanks for showing the burrs too.

Mike, when you can please post an intro in the introduce yourself section.in the meantime, welcome to the forum.

Bill