Model Engine Maker
Help! => Specific Engine Help => Topic started by: Trevorc on January 08, 2020, 12:59:53 PM
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I am building the Anzani Y configuration using the drawings produced by L Chenery back in the 1990s. In the build notes published in the Model Engineer he describes a novel method for finishing the bore of the cylinder liner.
He recommends boring to 1 inch minus 0.003 inches with a good finish and then forcing a 1 inch diameter ball bearing through the bore. This is supposed to give a burnished finish. My questions are: Has anybody experience of using this technique? What do you think? Is the surface finish suitable for retaining oil for cylinder lubrication? Any comments or observations gratefully received
Many thanks Trevorc
PS i had thought i had already posted this query but cant find it so i assume i had a senior moment!
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You did as I read it yesterday
I have heard of the method but no experience of using it. Not sure I would want to try it on a cast iron liner but steel would be less likely to go pop.
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You did as I read it yesterday
I have heard of the method but no experience of using it. Not sure I would want to try it on a cast iron liner but steel would be less likely to go pop.
Wot Jason said....
Cast iron doesn't like a lot of tension...very little ductility.....12L14 on the other hand....
Dave
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PS i had thought i had already posted this query but cant find it so i assume i had a senior moment!
Trevor if you can't find a post.. if you look under your membership it will show you your latest posts. Which includes a similar post to this one ;)
Yes I have been told it does work. Not my preferred method.
Jo
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make and extra cylinder liner and try it....it's just a piece of stock right?
Dave
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I've also read a number of references to this technique by HSMs, but haven't had the need or inclination to try it myself. For starters I think we shouldn't sell cast iron short. Certainly C.I. would have less tensile strength and malleability than a mild steel but unless the liner is cardboard-thin I would bet on C.I. to survive the process.
My thoughts (ie, misgivings) about the technique were because it probably had its origins in industrial production wherein all the variables are optimized and controlled to produce consistent results. In our workshops, not so much. Methinks ball material would be one of the most important variables. Another thing which always came to mind was galling and IIRC the accounts I read called for flooding the bore with lubricant. But what kind of lubricant? That could have an equally great effect on finish so unless we were very lucky or fortunate, our variables would, umm . . vary, and produce mixed results. What I would hope is that this is actually a brilliantly simple and consistent way for us to finish bores, even if the optimal variables are a bit off..
BTW, I have very good results finishing cast iron bores (for steam) using a fine-stone automotive brake cylinder hone.
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I have used it once, to finish bores for tappets running direct in a cast aluminium alloy crankcase. In this case I used a 1/4 bearing ball in a hole 0.002" undersize. I lubricated with graphite grease and put the ball through each hole three times for good luck. I used the pillar drill as a press, with a cleanly faced stub of rod in the chuck.
The result was exactly the polished, compacted surface, and slightly undersize hole, that I wanted.
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Roller burnishing specialist large cylinder bores has made a resurgence within Industry after the EURO Standards banning the use of hexavalent chromium fluids in 2017
This roller burnishing is a complex procedure that rolls over the edges of the micro surfaces in the actual tooling marking. Roller burnishing is these size applications does not present a recordable reduction in dimension [bore size]
You do not nominate the wall thickness of the CI liner, however a 1" bore would suggest something in the order of 1 1/4" OD or a wall thickness of 1/8" which would bring fear :facepalm: in forcing a 1" diameter ball into a bore undersize by 0.003"
As an alternate to this, you could consider producing the same sized bore [0.997"] out of you same CI bar stock [hopefully say 1 1/2" as cast], then trial pressing the 1" ball through the bore [then to leave external machining as latter processes]
Good quality spheroidal cast iron after final machining produces micro sized pores [with razor sharp edges] so a single pass of the single pointed [diameter] ball could well skate the surface and actually raise these razor sharp surfaces
Derek
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it goes by the unfortunate handle of ball sizing or ballizing. I haven't done it (a lapping man meself) but there are lot of variables, material, interference, even the speed of the operation. .003 interference seems like a heck of a lot for a 1" bore, but thats an opinion cast in ignorance. Before wrecking a piece, I'd be searching ballizing and double check the interference....lots of info out there provided by those trying to sell their sized balls.
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Did not think roller burnishing as the same process as that uses a head with several hard rollers to "burnish" the surface, balls sizing is the one being discussed.
(http://yamasa.com.tr/UserFiles/image/Advantages%20Of%20Burnishing(1).png)
For info the wall thickness is 5/64" approx 2mm. There must be a fine line between having things too thin and risking breakage and too thick which would not have enough malability to stretch to final size.
Also maybe Jo could confirm but I thought that Mike's castings used a steel cylinder and soldered on head in which case is a CI liner needed as the piston could run in a steel cylinder
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Also maybe Jo could confirm but I thought that Mike's castings used a steel cylinder and soldered on head in which case is a CI liner needed as the piston could run in a steel cylinder
Les Chenery originally did Aluminium castings for the Anzani Cylinders which could not be described a fine scale and needed a liner. Mike Cole, when he supplied castings, did not provide cylinder castings but pointed the builder to the two part Steel cylinder/head designed by Brian Fairey. As it is a Steel design it does not need a liner.
Jo
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Thank's Jo so would not work with the blind bore of Mikes version unless you did a CI liner in the steel outer.
Now there is a thought for something for you to print and cast - a detailed aluminium one piece head/cylinder :stickpoke:
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If you pressed the liner into the Chenery Aluminium casting before pressing the ball through you would not have gotten it out again the top of the cylinder would be in the way :toilet_claw:
Jo
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Depends how hard you push it...
:mischief:
AS
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I have been advised best not do this on CI liners that are unsupported as the liners crack :paranoia:
Jo
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What an amazing response. Thank you every one for your inputs. I didn't realise this was a recognised production process. I have a spare piece of material so i plan to give it a go after consulting internet sources. Will let you know.
Thanks
Trevorc
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Jason....the Yamasa product you show is possibly the World leader in this roller burnished surface technology and equipment manufacture..
https://www.google.com/aclk?sa=L&ai=DChcSEwi4v5GSwvfmAhXNCisKHRHKAwcYABAFGgJzZg&sig=AOD64_3FtCgbIG1jGCXF5A0-SW6HNJ7TMA&q=&ved=2ahUKEwjNnIySwvfmAhX_xTgGHZ7EAcMQ0Qx6BAgTEAE&adurl=
You would need a large wheelbarrow full of JP¥) :facepalm: to purchase a single No 2 MT head for 21 to 26 diameter...... & still not get enough change for a bowl of Fried Rice :popcorn:
Derek
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I asked myself, if I had to ballize a thin cast iron sleeve, just how would I do it? Shrink fit it inside a steel tube, ballize, then cut the tube off, perhaps?