Thank you Dan! Look everybody, there is some new information about our choice for rifling cutter tool steel. Very interesting, Dan, and only 32 km away from your house. FAGERSTA WKE45, fellas, if you ever need a long lasting cutting tool, this is the steel to make it from. Dan, the 'How to Make a Rifling Machine' thread with all the photos and diagrams of the Rifling Head internal construction is in the Forum Stickies, but temporarily unavailable,(I checked today). When it becomes available agin, you can go there to page four and look at the drawings and see that all the cutting is done bt the cutter which protrudes out of it's slot which is just in back of the chip recess. Enough cutting oil is brushed on the Rifling Head body, just prior to running the tool into the tube and bottoming it which sets the cutter height and then retracting the tool from the tube during it's cutting stroke. Gary, you are right about that, quite a spray! Just one more reason to wear safety glasses ALL the time in the shop. Dom, it is definitely more difficult to turn that chain drive hand-wheel when the old bits got dull. Chatter, in our experience, has more to do with cutter geometry, mainly rake angle, than anything else.
Thanks for that suggestion, George, maybe we can paint some lines on that shaft next time. I'm really glad someone noticed that bounce of the Rifling Head after it emerges from the bore. We will explain why it does that below the following two photos:
The reason for the bounce is simply a lack of solid support of the Rifling Head weight after it leaves the cannon's bore. The reason we did not provide any is more complicated. In the upper photo you can see a rectangular steel pillar at the tube's end. This was originally designed to be dual-purpose. It was supposed to block the tube from being drawn to the right, out of it's two, greased, carbide-faced, V-Blocks and indexing collar. It performs this function today. Also it was supposed to support the Rifling Head after it came out. We decided it would have to be a very complicated assembly, with extremely close tolerance parts to do this job correctly, especially if different sized heads were used which they are. Also we were concerned that it would perhaps be an obstacle and possibly cause a hump for the head to go over if it were sized just .0001" higher than the bore's bottom. This could cause the cutter to dig in near the muzzle, the most critical area of the bore. Not good.
In addition, you can see that the two inches of tube near the muzzle is turned so it can fit that bearing block for the gundrilling, chamber drilling, and reaming operations, (Reaming Op. is shown). We added two extra inches for these ops and the muzzle-end clamping during the rifling operation. These extra two inches are cut off after rifling is complete, so that any rifling irregularities due to the head being unsupported can be discarded. The bore is indicated and centered with a 50 millionths test indicator during the last bore related operation, that of crowning. We make a 45 deg. crown, carefully cut with a razor-sharp, left-hand, lathe bit, held in the compound.
That's about it. Thanks Soot for your comment, That, of course, is the real reason.
Rick, please re-read our first post's last sentence; the answer you seek is there.
Mike and Tracy