Honing

[bulldog93]

Okay I've been searching and learning about honing. I've had a look at a few web-sites and vids and this is what I've came up with.

Honing is a final finishing operation conducted on a surface, typically of an inside cylinder, such as of an automotive engine block. Abrasive stones are used to remove minute amounts of material in order to tighten the tolerance on cylindricity. Honing is a surface finish operation, not a gross geometry-modifying operation. Hones can be of the multiple pedal type (pictured below) or the brush type. Either type applies a slight, uniform pressure to a light abrasive that wipes over the entire surface.

The figure below illustrates the configuration of the abrasive stones of an external hone.

Below are illustrated bad and good honed part geometries. Both pairs of figures show that a through hole design is always best for coolant flow, etc. The upper pair shows that a certain portion at the end of a blind hole is not completely honed. The lower pair shows that a right circular cylinder is the easiest to hone.

A hone is a machine tool used in the manufacture of precision bores to improve the geometry, surface finish and dimensional control of the finished part. This process is called honing.

Typical applications are the finishing of cylinders for internal combustion engines, air bearing spindles and in gear manufacturing. Types of hone are many and various but all consist of one or more abrasive stones that are held under pressure against the surface they are working on.

The hone is usually turned in the bore while being moved in and out. Special cutting fluids are used to give a smooth cutting action and to remove the material that has been abraded. Machines can be portable, simple manual machines, or fully automatic with gauging depending on the application.

Modern advances in abrasives have made it possible to remove much larger amount of material than was previously possible. This has displaced grinding in many applications where "through machining" is possible. External hones perform the same function on shafts.

Cross-hatch finish
A "cross-hatch" pattern is used to retain oil or grease to ensure proper lubrication and ring seal of pistons in cylinders. A smooth glazed cylinder wall can cause piston ring and cylinder scuffing. The "cross-hatch" pattern is used on brake rotors, and flywheels.

Plateau finish
A tool with the brand name Flex-Hone made by Brush Research Manufacturing Co., Inc. was introduced as a hone with many of the benefits of honing without the need for labor intensive set up or training. The tool is often referred to as a "ball-hone" for its many abrasive globules mounted to the ends of flexible nylon filament. The result of using this tool is that it provides a cross hatched finish while achieving a plateau finish at the same time.

The Plateau Finish is one characterized by the removal of "peaks" in the metal while leaving the cross hatch intact for oil retention. The plateaued finish increases the bearing area of the finish, and does not require the piston or ring to "break in" the cylinder walls.

Other similar processes are lapping and superfinishing.

A few VIDS:

YouTube - H-D Cylinder Honing

YouTube - How To Use a Flex-Hone Tool


I'm still trying to find more info on the honing stones. If you have an info regarding honing please post. Also after more vids.

 

[bulldog93]

Stone lapping:
Principles of stone lapping, as shown below (stone lapping of outer diameter of cylindrical roller), are methods of surface finish with which fine lapping stones press surfaces of work pieces with low pressure, while giving rotation to work pieces. At the same time fine oscillation and a lot of metal work coolant with excellent washing effect are given to the surface of the work piece.
A microscopic cut creates a smooth surface finish and geometrically correct profile.
Low-pressure and low-speed process performed by stone lapping, produce less heat, and a lot of metal work coolant used for lapping operations removes deteriorated layers. Thus, its finished surface has superiority in resistance on wear and corrosion, and in lubricity. When applied to the part where wear is expected, a great effect is obtained.

 

[sean01]

awesome post mate... our convo earlier must of got the head ticking hey..

now obviously this info isnt for everyone but to those that are interested in a longer lasting engine read on.

most critical area's to be aware of, is that honing a cylinder too much increases the piston to bore clearance and also effects the ring gap...

before honing you should use a micrometer to measure the piston skirt to make sure it hasnt collapsed or worn too much...the piston should actually be at its largest size about mid-bottom of the skirt...if the size doesnt change from the oil ring down then the piston is stuffed

now also you need an inside micrometer or bore dial gauge to measure the bore and make sure its not too out of round and isnt tapered.

ok now you need to compare the piston measurement and the bore measurement from both their largest size.
if the clearance is greater than .003 thou it is recommended to rebore the cylinder or alteast measure a new piston to see if it will correct the clearance.

these china engines usually have a bore clearance of about 1.5thou. forged pistons about 2-2.5thou.
and the pistons used in them are crap, they expand really quick and are made from really soft material.
and also the cast sleeves in china engines are usually rubbish too, very quick wearing. also very soft material.

now also remember that honing the cylinder will increase the clearance, and by how much depends on how bad the cylinder is glazed and scored and by what grit hone stones you use..
ball hones(brush type) dont generally remove much cylinder material which is good, but on the bad side they cant square up the cylinder.

if you have an engine you have invested alot of money in, it is wise to have the cylinder nickel plated or at least replace the sleeve.

most the ceramic big bore kits you see are nickel plated..

 

[Hillz]

i've got honing tools if anyone interested!

 

[bulldog93]

Got pics of them set up? Or a vid honing a china motor?

Sean01: What do you mean by the skirt? Thanks for ou post to very informative.

Yeah it did actually. I was going to search for one of he honing tools but I doubt there'ld be any near me so I didn't.

 

[sean01]

$60 from supercheap TFT Engine Cylinder Hone - TF6800 - Supercheap Auto
check this out...not exactly a china piston but youll understand
http://www.tunedcar.co.uk/Engine/Images/piston.gif

 

[sean01]

haha i like that last vid in the first post....
we ll just wack the piston in the vise and tighten it up....lolz..please do not do this at home..

 

[Satchy]

That hone you posted Sean is just a tad bit big for china bores... there wouldn't be much left of the bore IF you got it in there... there great for car bores but not china's.
The next size hone down from that one will set you back $30 and is the right size, ive used it on my bikes 125 110 140 etc

 

[synergy17]

As for the "special cutting fluid" mentioned, at work we have found that automatic transmission fluid is another alternative to use, good lubrication and has good detergents in it.

 

[bulldog93]

Satchy do you have a pic or link? Where would people be able to buy honing stones? Synergy17: Could you just use normal oil?

 

[coolmodee01]

$60 from supercheap TFT Engine Cylinder Hone - TF6800 - Supercheap Auto
check this out...not exactly a china piston but youll understand
http://www.tunedcar.co.uk/Engine/Images/piston.gif

$60 is a rip off

i can get em heaps cheaper than that

 

[synergy17]

*bulldog*

as far as i know the reason why we use auto trans oil instead of "normal oil" is due to the detergents in the oil and its ability to handle heat. e.g. at my work the engines sit around 80-90 degs and the trans sits around 130 degs(wen theyre running right).

also wat do u classify as normal oil? petrol engine oil?

i will ask the OLD GUY at work for more info why we use trans oil intead of "normal oil"

 

[bulldog93]

Bike oil or car oil? Thanks that'll be awesome

 

[sean01]

That hone you posted Sean is just a tad bit big for china bores... there wouldn't be much left of the bore IF you got it in there... there great for car bores but not china's.
The next size hone down from that one will set you back $30 and is the right size, ive used it on my bikes 125 110 140 etc

you want to clarify why it is too big???
it is rated @ 2 inch to 7 inch....

last time i checked a china engine is bigger than 50mm... so it is the perfect size..

$60 is a rip off

i can get em heaps cheaper than that

where you buying them from...trades prices doesnt help everyone

 

[Satchy]

Didnt read the details, no need to be a smart ass about it.
Still think its overkill for honing small bike engines when you can get the next size down to do the same job for $30.

 

[sean01]

lol, whos being a smart ass....

and if you had used one before then youd know how they work.... they have an adjustable preload spring for pressure on the stones..

and next time read the details before talking sht...
now i am a smart ass

 

[y0 ash-tray!]

used a hone at trade school, also used motor oil as a lubricant,
with the motors we rebuilt little 3Y toyota motors,
we used a air drill making sure the up and down motion of the drill was at a good speed
and got a 120degree crosshatch on the bore,
after that wash down with warm soapy water and dry out using air and lint free paper towel, eg Rag on a Roll
if you wipe the bore with white towel and still get a grey mark on the towel keep washing until you can wipe down a bore and are able to eat off the paper afterwards

if the bore is in good condition, not much honing is needed
then again if the bore is damaged cheaper to replace than bore out a fit over thou pistons
________
Bmw z1

 

[sean01]

i forgot to add some info in regards to cleaning a cylinder after honing...

you must degrease the crap out of the cylinder a couple of times and use a round brush(like a toilet brush) and with degreaser use the brush to clean it in the same way you honed it...

and repeat again using hot soapy water and the brush a couple of times...

failing to do so can result in worn rings again as microscopic crap in sitting in the hone marks.
this could kill new rings in a matter of hours of running...

also for hone lub/oil, i have always used wd40(proper sht not supercheap sht). as i have found motor oils clog the stone up...
but i have never tried auto fluid, which i will next time...

oh too late for that info...oh well...

 

[Satchy]

Sorry, i forgot you take great offense when someone try's to correct you EVEN when that person is wrong. haha
I admit it was a mistake on behalf no need to go flaming me, **** theres no room for mistakes on a forum...

Pfft thats all from me, mod can probably delete this stuff...

unless this hero wants to make another comment or he might man up and and act his age.

 

[sean01]

turn it up mate....i simply asked why you thought the hone was overkill.... there were no smart ass comments ..
iv your not paying attention , i cant see the need to post....
my second post to you was showing what its like when i am a smart ass.

now as for the hone...i use mine weekly and it is far from being overkill....the stones arent that sharp and you need to screw the preload up are fair bit....

why do i need to man up...

this thread was obviously started for people to gather correct information about honing...

and if you find the tone in my messages a bit harsh then i do apologize for that. thats just me...