Super Finishing By Honing. Hard vs. Soft Jobs

A. The word hone now refers to a couple of different cutting/polishing process using a heavy use of water. Probably you are referring to a lapping type machine process rather than a wet abrasive or extruding process. I think when you refer to hard or soft, you are talking about the material to be worked. This is not my area of expertise, so I would recommend you get in contact with the people who manufactured the machine system you are using or want to use. Each machine manufacturer has different parameters concerning size and speed on specific applications.

A. Hard means after heat treatment and soft means before heat treatment. Honing finish mainly depends honing stone properties, feed rate of the honing tool and RPM of the honing tool along with the cutting fluid. Plenty of books are available in the market for this. Hope I answered your question!

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Ed. note: The ASM Metals Handbook volume on Machining has a good chapter on honing, and used copies are usually available quite inexpensively.

A. Sir,

For what its worth , size control and final RMS finish of the part is operator dependent, if for example an operator were honing a cylinder bore, and was "overstroking" the work he would create a venturi shape. If the same operator were to "understroke" the work, he would create a barrel shape since the stone are spending more time in the middle of the work. it is also possible to get TA taper with still another "stroke" of the work. This same thing can happen in O.D. honing, with variations in stroking technique the operator can create straight, convex, and concave shapes, as for the final finish , the operator may choose a corse stone with large stock removal in mind then switch to a finer stone that will meet the specifications of the print.

My thought is ... if your tube "out of the box":

1. meets the RMS requirement (which will be important for the backup rings and seals, especially in high pressure systems)
2. meets parallel requirement

I see no apparent need for the hone.

DEAR MR. BRAD SAWYERS,

THANKS A LOT FOR YOUR FEEDBACK ON "HONING". ACTUALLY WE HAVE ANOTHER DOUBT NEEDS TO BE CLARIFIED. NORMALLY THE TUBES ARE SUB-CRITICALLY ANNEALED TO RELIEVE THE INTERNAL STRESSES BEFORE HONING. BUT TO AVOID HONING THE TUBES WILL BE SUPPLIED IN "AS DRAWN" CONDITION WITH INTERNAL STRESSES. DO YOU THINK THIS MAY "AFFECT"THE PERFORMANCE?

LET ME THANK YOU IN ADVANCE FOR YOUR KIND ATTENTION ON THIS.....

A. Apart from surface finish another reason for choosing honing alternately to grinding, extrusion, reaming is for the cross hatch section produced during the honing process.

The cross hatch section during the honing process is useful in cases where the oil retention in the cylinder helps in better lubrication since the oil film has small pockets in the cross hatch which acts as reservoirs of oil. Since this is very small and doesn't meet the normal visual perception one may tend to ignore this.

A. Sir:

Provided the initial hole is straight, taper will come from wear of the stones and from thermal expansion (either the tube or the mandrel). Any method that controls these variables will eliminate the tapering. Stones that last longer and sufficient cooling and frequent back and forth travel of the mandrel are routine. If actual stones wear fast try borazon or diamond.

Regards,

A. Your question is very complex and can not be answered with a simple one paragraph answer and that is probably why no one has answered it. There is not a lot of information out there concerning any mechanical processing equipment except that put out by the manufacturer of the equipment.

I have tried to classify all material removal systems in my book, but there is no organization that oversees technical data as you are looking for. Regarding honing: You are dealing with at least 2 main factors.

1. The abrasive and

2. the liquid.

Basically, how these factors are applied is what makes the difference in machine systems. Meaning, how the energy or force is applied to the abrasive is very important. Rather than go into an extensive detail, I suggest you check with the manufacturer of your equipment.