live in australia and its difficult to get some things here, trying to locate a good cylinder hone for small bores 3/4" to 1 1/2 or there abouts any suggestions welcome. have looked at ammco but start to big
I support Swifty with this. I have used brake hones with success and if you get the right one it comes with some finer grit stones for the final finish. One technique that I have recently used on a small bore is a split wooden lap that uses a wedge to spread it. You use valve grinding paste and it is done in the lathe.
Have a look at the myford boy website in the video describing the building of his stove stirling fan. http://myfordboy.blogspot.co.uk/p/blog-page_27.html.
Cheers,
Kerry from OZ
Ill go against the grain here. Brake cylinder hones are not a great solution at all. If possible try and locate a set of wrist pin hones, they keep the bore much straighter...
The proper type of hone for cylinder bore work is a rigid hone. It will provide a straight bore with the proper dia. and finish. When I was building my Hodgson 9 cy radial, I knew from experience that a brake cylinder hone was marginal at best and a true PIA to use. So I bit the bullet and bought a Sunnen P-180 portable hone. Like all quality tools, the price was high; I paid about US$500 for the complete kit including a Mitutoyo dial bore gage. I expect to recover at least 50% of my investment on eBay after my engine building itch has been scratched.
Anyway, after a bit of practice and experimentation with the set up, I was able to finish all cylinders to ±.0003" over the full length and with the proper cross-hatch finish for fast break-in. And it didn't take all day to do a cylinder. I bored them to .002" under on the lathe and honed them to size in the vertical mill. I think it took about 30 min. per cylinder after I got the hang of it.
Sunnen is not the only brand of rigid hone but is probably the most widely used. Sunnen is available in Aus:
Watson Specialised Tooling Pty. Ltd. 43 Wyandra Street
P.O. Box 2039
Fortitude Valley
Brisbane, Queensland 4006
Australia
Don T. Watson, Industrial Sales Director Ken Watson
Tele:61-7-3-252-4976
Fax:61-7-3-252-3934
thank you all for info, did try brake cyl hones but found not quite true enough consistently, sunen i shied at price and missed the p180 size but will get a quote and go that way as much as the price will hurt i like the accuracy and true bore first.
A brass cylinder lap is a better tool, as it will maintain bore size, unlike a spring hone which with short cylinders leads to a barrel shape. You can make one as well. They are size specific, but can be turned down very easily.
talked with the sunen man and found that it is ratio of length of stones to bore length that is a major part of true bore. i can hone a v4 howell bore reasonable with brake hone but a atkinson diferential cylinder is 5" long
this is where i had bad experience with brake hones. so if i get a quality 3 prong hone with several length stones and grades it will should be ok with care for light running model engines. the sunen is $500 plus $140 for each mandrel and there is a lot of mandrels to do 3/4 to 1 1/4 diameters.