Domed Heads jig for creating the domes
Posted 16 June 2012 - 03:09 PM
This little jig is the prototype so, there might be some very slight changes to streamline the process or improve it, but it works pretty well. It works best on soft materials such as copper, nickle/silver, fine Silver, or Gold. The tools are not hardened, but could be for working harder materials. I got my original idea from Dr Jim Batson at a hammer In a couple of years ago. He took the time to draw his system, which was very similar to what I made.
The idea is to punch out small discs, dome them, and put a hole in them if a hole is needed. Some makers solder the pin in the cup of the dome....... so that particular one would not need a hole. It's mate on the opposite side of the handle, however, would.
Here is the main tool block and the punches.
Posted 16 June 2012 - 04:15 PM
The next thing is to take the disc and put it into the next hole that is cupped shape. It was drilled with a ball mill. It was slightly scratchy in the block so to smooth it some, I chucked the round punch in the drill press and put some lapping compound in the hole and spun the punch in it. That evened the punch and "mold" into the same shape. I tell you this because it is something you will likely encounter if you make one.
Posted 16 June 2012 - 04:24 PM
The dome is shaped with the punch that is shown in the middle of the first picture above. Then the dome is sit down into a second,.... no.... third hole, which has that shape but also has a hole in it exactly in the middle. Then the hole is punch with a the punch shown in this picture.
Posted 16 June 2012 - 04:32 PM
This just shows the pin stock slipped through the dome. At this point the dome can be cleaned up, the bottom flattened, The hole countersunk, and the surface polished, at least down around where it sits on the handle material. All of these operations presents its own challenge because of the small size of the piece.
Posted 17 June 2012 - 05:04 AM
This construction is quite strong due to not only the physical strength of the dome, but the fact that the soft Silver work hardens when you dome it in the block. This enables it to withstand the light hammering to shape the pin's head.
Another "plus" of this type of construction is that you can undersize the pin to allow for contraction and expansion of handle scales. There is also evidence that some of the early knives had a tube in the handle for the pin to pass through, the tube projecting out of the handle scales and up into the underside of the dome to provide some added strength/support while, at the same time, being covered by the dome.
Posted 17 June 2012 - 05:48 AM
Posted 17 June 2012 - 06:19 AM
Some good questions I was sort of expecting. The stages get progressively smaller, as you might think. Mine started with the disc as .240, then using the doming punch, push it down into a hole in the block (with a domed/cupped bottom)of about .230. This same hole is where you would punch the pin hole in the dome/cup. If you are not going to punch a hole in the Silver dome, dont hit it too hard or it will leave a halo on top. You can have a seperate hole in the block with no center hole. But the center hole is handy in the event the dome gets stuck and you want to be able to push it out from the other side.
It doesn't matter the actual size just so the set up produces the sized domes that you need for the particular knife. I can imagine needing two set ups for different sized knives.
If you are expecting to make a lot of these, you might consider using an arbor press to hold your punches. But it's not difficult to use this manually.
Oh, the stock is .020 for the cups and my pin stock is .082 I keep a numbered drill (slightly larger) dedicated for this set up in my kit. Your kit might be different according to your available stock but the results will be so close it would be hard to tell any difference.
Posted 17 June 2012 - 07:46 AM
Posted 17 June 2012 - 11:05 AM
Posted 17 June 2012 - 03:46 PM
The finshed product ready for installing in the handle.
Anvil Top Custom Knives
Posted 20 June 2012 - 08:10 AM
Very interesting info from both of you...thanks. I will have to try this because it looks "challenging" I am curious about a tool I saw while looking on a certain knifemaking suppliers website. It's called a "headspinner", and apparently will round the head of a pin on stock up to 1/8". Clearly this tool is meant for another purpose as it is not a mechanical fastener, but when would someone need to use it?