A simple chucking hone

This Forum is dedicated to the Hobbyist I.C. (Internal Combustion) Engine Community.

Moderators: JackF, Harold_V

Post Reply
Doug_C
Posts: 1254
Joined: Sat Jan 04, 2003 6:48 pm

A simple chucking hone

Post by Doug_C »

If you have ever lapped in a bore this could be a welcome change and somewhat similar in action to current industrial hones.
Having the need to hone 5 cylinders for a project, I wanted a simple mandrel to duplicate the action as seen in the production hones. I have in the past had the, eh-uhm, pleasure of honing thousands of parts on a manual hone machine. In recalling the design of the mandrels and stones used on this equipment, I needed to simulate it’s simplicity with the same concept.

As you can see in the drawings the machining is not complicated. Some explanation might be handy.

The hone stone is nothing more than a taper of aluminum and a piece of honing stone cut from a full size engine hone insert, glued together with epoxy. The sides of the stone assembly are lined with cellophane tape to help size it to the slot in the mandrel and give it a non-abrasive sliding fit.

The mandrel material itself needs to be softer than the cylinder to be honed. The reason for this is, as the stone breaks down, it is not the only cutting surface. Just like a lapping mandrel the grit is embedded into the softer material and is also helping the cutting progress. As the stone wears, just grab the bolt between your fingers a bit every now and then while it is spinning to keep the stone in contact and cutting pressure constant.


Chucking the mandrel in a lathe it is possible to hone very quickly and accurately to size, roundness and as straight as the original bore. Taper depends on how the stone is set before starting.
With the hone stone in the slot on the mandrel, a 5/16-24 bolt in the threaded end can be adjusted to force the stone up the ramp. That places pressure on the stone moving outward. As the stone breaks down during honing of a bore, it is imbedded into the mandrel and continues to cut. A flushing oil helps the progress.

It is strongly recommended that you make a sacrificial truing ring that can be reversed (Flipped end for end) every so often to re-dress the stone straight. This should minimize irregular stone wear, unless it is desired, like taper, typically with the small end toward the combustion chamber. Check the bore diameter often until experience is gained in how fast it is cutting.
A sleeve holder can be fabricated out of almost any material that is in the junk box. As shown on the drawings, just clamp a piece of emery cloth in a loop to help grip the OD and give something to aid in pushing and pulling the work piece in the stroking operation. If the work piece slips or catches it will tear the cloth and not your skin.
With a little practice it will be easy to obtain the 60 deg. Cross hatch pattern at different speeds. A couple hundred RPM or less will be sufficient. Just use plenty of oil and protect the lathe ways by cleaning before more lathe work is done.
All of the dimensions can be adjusted to fit your particular application. Even fashioning an assembly for blind bore honing using a setscrew and a spring to apply the cutting pressure. The end results are the only thing that is important.

If the quality of the drawing is poor, move your mouse pointer off the page and return it. There may be an option in the lower right corner now, to make the picture larger/clearer.

DC
Post Reply