ETW's Wyvern Gas Engine

[Tennessee Whiskey]

I think if you look from the driven end both lathe and drill chucks are turning clockwise. I am not sure, but, I think this is the way rotation is noted. You have been right all along if this is correct.

Yo Redneck,
Eric

[Maryak]

That means that the cylinder will need to be in the chuck. I often hold the cylinder in my hand  or rest the bigger cylinders on the cross slide:



Jo

And...................relative to the cylinder which way would you say the hone is rotating if the lathe is in "Normal" forward gear?

[Tennessee Whiskey]

Clockwise. I guess that is what I was trying to say. May have just came out in redneck terms.

Eric

[Jasonb]

Jo you must be running the hone clockwise as the various ends fit onto a standard R/H thread, if you were running the hone anti-clockwise the end would come unscrewed.

I tend to use the drill press and hold the liner in my hand



J

[tel]

That means that the cylinder will need to be in the chuck. I often hold the cylinder in my hand  or rest the bigger cylinders on the cross slide:

Where it will still (viewed from the back end of the hone) be rotating clockwise

[Jo]

Ok it goes clockwise  .

Jo

[b.lindsey]

Jason,

I am curious as to the concoction you are using there in that little cup? Almost looks like the beginnings of a pesto sauce but I know that can't be it

Bill

[Jo]

I am curious as to the concoction you are using there in that little cup? Almost looks like the beginnings of a pesto sauce but I know that can't be it

I assumed that he had been using it to catch swarf curls in 

Jo

[pgp001]

Tangler,

The ones from Polly are way too expensive.

You can get a 4 in 1 set from Sealey for around £20, and they work great for honing out bores to parallel and roundness.

I have used mine many times, and they do a great job.

http://www.amazon.co.uk/Sealey-VS029-Cylinder-Hone-4-in1/dp/B000RO7THQ/ref=sr_1_3?ie=UTF8&qid=1366859414&sr=8-3&keywords=cylinder+hone

John

John

I am not convinced that the results of using a spring loaded hone will give a truly accurate parallel and round bore. If anything the stones will tend to follow the shape they are spring loaded against.
These hones are great for "glaze busting" when cleaning up old cylinders, but not for correcting errors.

A delapena type hone uses a completely different method of applying pressure and guidance to the abrasive stone, this ensures only the "high spots" are removed and the stone does not remove material from the troughs as well.
This is an interesting website with some good info. http://www.delapena.co.uk/honing.html

I was extremely lucky recently in finding a Delapena "external" hone for doing outside diameters on shafts, I will be using it to finish the valve spindles on my Pollit & Wigzell Corliss engine.
http://thebloughs.net/hobbies/metalworking/ext_hone/

Just my 2p worth
Phil

[Jo]

Phil: Bruce engineering (now Polly Engineering) do kits for those as well. I used mine to do the R&B  .

Jo

[Ramon Wilson]

Hi guys, 

Have to agree with Phil here - the two or three stone cylinder hones will not true up an out of round or tapered bore - it doesn't take much to see that spring loaded, they will just follow the bore.  I have a Delapena external hone which does true the bore but this is an entirely different kind of hone. If a hone of that sort is not available then the best way of truing a bore with the usual kit at our disposal is to make a lap and use compound. At a push valve grinding paste as mentioned can be used but is a bit coarse - even the fine end - but silicon carbide powders are available in a range of grits - I have 240 thru 1000 which is mixed with a drop of thin oil.

Diamond paste is much more readilly available however a note of caution - if using this on soft material, ie unhardened, then the part needs cleaning in an ultra sonic cleaner to rid the surface of particles which will have embedded. Washing in the usual solvents - paraffin etc will not do this completely. Maybe not so important in a steam engine bore but in an I/C engine an ideal aid to running in - and out again 

Ramon 

[Bogstandard]

This time I will disagree with you.

Surely this isn't another case of the loadsa money gets better results brigade?

OK if you have the money to buy expensive specific bore internal hones, but think of the average man in a workshop, and there must be thousands of us out here using this type, who swear by them.

If they are used correctly, they WILL get rid of tapers in bores, and low measurements down the bores after boring, because I have done it, many times, and will continue to do so in the future.

Jo, I too have bought some of those external hone castings from Polly, they must work out a lot cheaper than Delapena. Do they work OK?

Ramon, there is a big difference between honing and lapping, similar process, but definitely not the same.
Lapping an i/c engine bore shouldn't really be done, it should be honed (to break glaze and to straighten out any imperfections), then allow the piston and cylinder to bed themselves in during normal running in.
I only lap when a superfine surface is required, Stirling engines, flame lickers, steam engines etc.

BTW, how does your Delapena external hone clean up an internal bore, are you holding back on us?


John



           

[Jasonb]

Jason,

I am curious as to the concoction you are using there in that little cup? Almost looks like the beginnings of a pesto sauce but I know that can't be it

Bill

Parafin (kerosene) just feed a small amount into the cylinder and it stops the stones clogging. There is quite a bit of aluminium swarf in teh bottom as I use it as a cutting fluid on ali.

I have used them to take out a slight taper, just play the home where the dia is smaller and keep taking measurements until its the same all the way through. They won't correct a mis shaped bore though.

Lapping pistons into lapped cylinders is common practice on small glow and diesel aero engines, not sure where you got that from John.

MEB had an article and drawings a while ago for making the external delapena type hones.

http://www.modelenginebuilder.com/issuetwentyfive.htm

[Bogstandard]

Sorry Jason, I was on about ones with rings, like Jo's R&B.

But I did also straighten out the bore on my Scott flame licker with one of these honing kits, when I had a high spot in the middle of the bore.



John

[tangler]

Thanks for all the input guys.  Clearly a difference of opinion.  At less than £20 quid it's going to be a cheap experiment - I can always fall back on the home made lap.

One other question (for the moment).  The piston is an ally casting, I'm guessing LM4 and will have 2 cast iron rings.  The co-efficient of linear expansion of LM4 is about twice that of the cast iron cylinder so I feel I ought to leave a bit of a gap when cold - but how much?

cheers,

Rod