Author Topic: The Oliver Tiger Mk III - a 5cc Version  (Read 2382 times)

Offline Tennessee Whiskey

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #30 on: February 10, 2019, 12:37:53 AM »
You aint just a tooting, got both eyes on ya. As a matter of fact; couple of those holes look a bit large to me  ;) 8).  Just saying  :lolb: 

Whiskey

Offline b.lindsey

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #31 on: February 10, 2019, 12:42:34 AM »
Those crankcases are looking terrific Tug. Pay no attention to that good old boy behind the curtain  :lolb:

Bill
« Last Edit: February 17, 2019, 10:07:41 PM by b.lindsey »

Offline Neil-Lickfold

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #32 on: February 10, 2019, 05:10:44 AM »
In the case, having the case to shaft with a clearance of 0.03mm to 0.05mm on diameter is just fine. More than 0.05mm on diameter and the front bearing will get more lube. Less than 0.03mm on diameter and the front bearing will run in a more dry state. At 0.02mm in diameter, it will run the risk of picking up in the housing. The pick up occurs because of the flexing of the crankshaft between the bearings when it fires. This is why there are sometimes radial score marks seen on the crankshaft of some engines. The higher the RPM and load, the more the crank can bend. On some engines, they have 0.07mm of clearance between the crank and the housing. It is common to have the housing a nominal to +0.01mm on diameter housing, and then relieving the crankshaft between the rear bearing and the front of the shaft by 0.04 mm or so on diameter. It also makes fitting the rear bearing a lot easier as well, and also means that only a short distance for the rear bearing fit is required.
Neil

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #33 on: February 10, 2019, 09:41:38 PM »
Hello Guys, thanks for looking in.

Now you didn't say Whiskey but which two holes are they :Lol: Never fear Bill I know just what the old boy is up to ;)

The info on clearance is interesting Neil. I usually reduce the shaft in front of the bearing but not as much as you are suggesting going for more of a seal than allowing too much leakage. All made so far of course (save that Racer previously mentioned) have run without issues and though running fast at times are not running at anywhere near peak RPM's which would probably make a big difference. Given what you are saying and AS's comment on the bore being opened offset I think I will increase the annular gap slightly more than before on these, maybe one more so than the other for comparison.

All assuming of course that we end up with decent cases  ::)

As said yesterday it was a case of the old two step shuffle - one forward one back. I had set up on the face plate to rough turn the front bearing housing OD. Removing it I realised I could have roughed the ID to to ease the final operation at a later date. Set up the second one and bored it for the 8mm depth required, did the other then set the first up to do the same. Noticed on the drawing I had dimensioned this depth as 6mm so pencilled in the 8mm. It would be later in the evening dozing in front of the box and musing on the day that it hit me - the bearings were 8mm ID not 8mm thick. Not only had I not read my own drawings I'd operated on brain fade and amended the drawings to suit - Well bless my ****ing soul I thought - actually words far far worse :facepalm: :facepalm:

So, after turning some close fitting ring inserts back up goes the face plate, and the rings Loctited (638) in.


A quick mandrel was turned from a bit of scrap and held in the drill chuck to hold and keep the rings from twisting and the ring pressed home tight.


Gutted, and so sodding cross that such a mistake could be made on not one but all three cases never the less the reclaim has worked well and should have no detrimental effect on the finished case. I'll put it down to an age thing - I'm certainly feeling it these days.

Back on stream the top was brought to finish on outer dimensions and the lower side waste roughed away leaving .5mm to finish. The case was then set up on a close fitting mandrel to bring the width to size and finish the lower face of the bearers true and parallel to the bore centre line.


And slowly, they are beginning to lose more weight


Final roughing op was to reduce the lower case ready for profiling


And this is current state of play with all of the major roughing completed


Next up is to make a couple of fixtures for holding on further ops - everything will slow right down now as it will be all too easy to remove areas that don't need to be but now the fun bit begins :)

Weather's looking good for next week so the garden may have some influence on shed time

That's it for now - 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 Tennessee Whiskey

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #34 on: February 10, 2019, 10:02:19 PM »
Heh heh heh, the proof of a proper machinist is one that successfully rectifies his error without scrapping the part. Nice save Tug. Let Sue dabble in the garden and you wont have to leave us in suspense, just saying  :stickpoke:

Whiskey

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #35 on: February 11, 2019, 08:14:25 AM »
Ha, Whiskey, now I'd say the proof of a proper machinist is one that doesn't make that sort of mistake in the first place  ;D That said of course I've long followed the principle "those who have never made a mistake haven't made anything"  ;)

There' more than a bit of dabbling - I don't think she'll be too keen to dig and prep my dahlia patch :ROFL: Nice thought though - I'll give it a try  :)

Never fear, I don't intend to take too much time away from these

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 Neil-Lickfold

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #36 on: February 11, 2019, 10:11:35 AM »
It is nice to see that someone else also uses printer paper to hold parts better in the vice, as well as the added benefit of no marks on the work piece faces.
Neil

Online steamer

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #37 on: February 11, 2019, 11:11:10 AM »
"......"those who have never made a mistake haven't made anything"


Beat me to it Tug!   Glad it's sorted and you're back on track.

Dave
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Damned ijjit!

Offline Roger B

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #38 on: February 11, 2019, 11:46:09 AM »
Nice save  :ThumbsUp: and good progress on the build  :praise2:
Best regards

Roger

Offline Allen Smithee

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #39 on: February 11, 2019, 01:18:03 PM »
"those who have never made a mistake haven't made anything"

In which case I wish to claim to have been the most productive human ever to walk the face of the planet...

 :-[ :-[ :-[

AS
Quidquid latine dictum sit altum sonatur

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #40 on: February 13, 2019, 09:38:17 AM »
I plan on doing a few versions of the old Danish Viking 2.5 followed by the extremely rare Viking 3.2 (a bored 2.5) and almost doing one of your specials, a Viking 5.0 - with the exception being I'm only increasing the bore, since the original is extremely long stroke = tall. This way I can use the same stock for all the versions. I got almost all the materials now, but still have to get more tools.

Hi Per - sounds good to me  :ThumbsUp: I'm not familiar with the Viking - do you have an image of one?

Neil as I'm sure you know its a very old trick but one not to be dismissed, that simple bit of paper makes a huge difference to gripping power - of vise or clamping  :agree:

Made a start on the fixtures yesterday - should be finished today and the shaping can get going

Back soon - Tug

PS - AS, how can you possibly claim to be the most productive human ever to walk the planet when you tell us clearly that you come from middle earth  :headscratch:
"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 Allen Smithee

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #41 on: February 13, 2019, 01:36:39 PM »
Because I am clearly not there now - one does not simply walk into Mordor...

AS

(Winter is coming!)
Quidquid latine dictum sit altum sonatur

Online Jo

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #42 on: February 13, 2019, 04:32:11 PM »
(Winter is coming!)

I would be more worried about the horizontal freezing rain driving across the runway ::) Enjoy watching Netflix

Spring is here down south   :cartwheel:

Jo
Usus est optimum magister

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #43 on: February 14, 2019, 10:39:27 PM »
Hi guys

Just to let you know that despite two very nice distracted days in the garden (had a really great start of the season bonfire :) ) some time to make a start on the initial shaping has also been found  ;)

As said  a couple of fixtures were required to be made and first off was to profile the lower part of the case. One of the fixtures was for this small 4" diameter tilting rotary table on which to mount each case.





A first cut was made leaving about .25 mm to clean up




Then the finishing cut done in quite small increments to minimise the amount of filing that will come in due course


The lower areas behind the bearing housing were treated in a similar manner and a start on the area above the mounting lugs on one of them. This was the current state of play tonight.


Doesn't seem much since the last post but another dual purpose fixture has also been made for machining the top areas - Rome wasn't built in a day as they say  ::)

It's a matter of slowly 'picking' away at the shaping now taking one small area at a time and doing it on each case before moving to the next bit. Very easy to machine away something that you don't want to so 'steady's the word Jack'

Hope that's of more 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)

Offline Ramon

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Re: The Oliver Tiger Mk III - a 5cc Version
« Reply #44 on: February 17, 2019, 08:27:02 PM »
Hi Guys - a few more pics of the latest progress.

I've decided to break this down into three stages, the first to be the surfaces below the engine lugs, the second will be around the top and the last will be the difficult one around the venturi inlet.

The lower 'pockets' were cut first, establishing the lower web width and the lower faces of the side webs


A step over chart was drawn and the profile milled with a 1/8th ball nose slot drill.


Inked up with a felt tip ready for the ops I enjoy doing most - the 'fettling'


Initial stages using a tapered 3mm diameter carbide burr in a Dremel type power tool running at about 10,000rpm


Front ends done ready for shaping the slight curvature in the rear portion


Lower faces all done.


Final(?) 'finishing' was done with a mounted grinding point running at far lower revs - just a few hundred and ostensibly 'sanding' the surface. Lots of paraffin used to stop the grinding point loading up. The surface texture looks far worse than it is in the hand. Intention was to finish these surfaces as previous engines - smoothing them and then bead blasting. This actually looks much closer to the originals engine's surface texture so it will be left as is for the moment until completely finished. I am hoping that bead blasting this surface as it now is will give a good representation of the cast original.

Next phase is to do the top - hopefully get a start on that tomorrow.

Hope you are getting too bored with these pics - they'll be a bit 'same-ish' for a while yet

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)