Another round stock drilling question

[rbortnem]

I appreciated all of the suggestions for locating the center on round stock in the previous post. I need some tips on the best way to drill out frozen pins in round shafts. The starting point is obvious in this case but it seems tricky to make sure the original hole is vertical before you drill.

 

[Kentb of SWMO]

There in NO easy way if the pin is broken off. I have done something similar in having to drill a hole in a shaft to match a hole in a gear. I do this building a different oil pump shaft for the Early Chrysler Hemi engine. What I do is remove the old shaft. Put it in a 5C collet holder on my mill. Then I put a long dowel pin in the hole of the shaft. I then mount a dial indicator on the mill spindle. Move the spindle up and down to see if the dowel pin is exactly vertical. If not vertical I move the shaft slightly in the collet until it is vertical. I then block may setting, remove the old shaft from the collet and install the new shaft so I can drill the new hole.
If you have nothing to indicate or you are trying to do this by hand it is almost impossible.

Kent

 

[Dick L]

I would fashion a type of C clamp and use a square if you are not in a tool shop. All depends on the diameter of the frozen pin you are drilling on how square you have to be. On a small hole if your real close the drill will follow the hole. I would use a Vee block to lay the shaft in. A new hole is something different.

I am heading out to my mold shop to drill 60 holes with 12 of them to be tapped for threads.

 

[Little Ed]

You could weld up a vee block using angle iron welded to a flat plate. It doesn't need to be exactly 90 degrees, it just needs to support the round stock. Lay the round stock in the vee, (or lay it on a table if you can't get the vee made)with the end of the dowel facing up. Take a file and holding it parallel to the ground, make one swipe along the top of the shaft, all the way to the end. This will make a very light line at the very top of the shaft. Turn it over so that the other end of the dowel is up, and do it again. By doing this carefully, you will have two lines 180 degrees apart on the shaft. Go down to where the lines run off of the end of the shaft, and make a mark connecting the two, on the end of the shaft. I like to use Sharpies or a pencil so that I can remove any lines that wind up in the wrong place. Now you can eyball it for perpendicular, or use a square off of the table, or lower your drill bit, if you are using a drill press, and use it as a gage to line up with the mark. It is easier to do than to explain. If you can, make the vee block, It is hot rolled, so you won't dull your drills when you break through. And you will use it again; it's handier than a hole in a nitegown. If you have access to a couple of friends, use them as spotters from different places and you can do it by hand. Poor folks got poor ways. I think that the dowels themselves will give you more trouble than the alignment. The dowel pins we use are hardened, and are hard on regular drills. I usually use carbide to drill them out. (lots of speed and pressure). Hope you can make sense of this.

 

[rbortnem]

Yes, I can follow you. Thanks. I think I'll weld up some vee blocks for future use.
The shafts I'm working on are from a Rest-o-ride seat from a Ford Tractor and are kind of "Z" shaped only with right angles, so it's going to be awkward to use any jig. I'm going to try a lot of heat and a punch first. I'll probably be back to this forum later asking advice on how to fill in the deep wear grooves in the shafts so there is support for new bushings.

 

[Little Ed]

For building up old worn shafts, I was lucky enough to get an incredible deal on a TIG welder many years ago. Not too many people have that kind of access, so the next choice would be wire welding, then stick welding, (I think wire welds grind and file easier)but if you need to, brazing it up with a torch and working it down with a file can be done quite quickly, and looks good when you are done. Good luck.