Jig Bore Handwheel Repair

A few weeks ago I told the story of how I ended up with a damaged Kearney and Trecker Autometric jig bore. As the machine sits in the shop I'm starting to get very curious how I might use this machine. Having a horizontal spindle is a very useful item in any machine shop. The question is how can I use this machine and is it worth the floor space it will take up. Regardless of all that I need to fix some of the damage from the previous owner and get it in running condition so I can play with it or trade it for something else.

Fortunately the damage to the machine was minimal. The nice cast iron handlwheels absorbed most of the energy from the tip over. The shafts that the handwheels were on were not bent so I was glad to discover that. I thought about just buying some similar sized commercial handwheels, but on closer inspection I had all the broken pieces of the cool old school cast wheels. This makes for a interesting repair job.

The wheels are around eight inches in diameter. I thought it was weird that they weren't the same diameter. Maybe this in one of the reasons they went out of business? Just looking at them they looked the same but when I measured the OD with calipers there was around  three eighths difference in the OD. At least the center shaft size was the same at five eighths. What was needed here was a fixture to help me align the broken parts and keep everything concentric. Its important that the handwheel run reasonably true and in plane.

A simple plywood fixture was created to hold everything together. I started with the smaller OD wheel so I could re-cut the fixture for the larger wheel if it all worked. I just cut in from the side for the part with the hole. This allows me to squeeze the gap closed to actually clamp the part a little. All that I needed now was the center alignment shaft.

Got lucky that I had some five eighths steel rod around. I turned the end down because I didn't have a five eighths diameter Forstener bit. Forstener bits are the cats meow for accurate holes in wood. I'll pick up a five eighths Forstener this weekend. I hate to be held up by tooling issues.

The handwheel in the assembly fixture. You can see I closed the gap up and shot a couple of screws into the ears to clamp the wheel tight.

I used a mini grinder with a Walter abrasives Zip cut disc to gouge the cracks for welding. The areas I couldn't reach with the grinder I ended up with a carbide burr on a die grinder. The goal here was to get this securely tacked up and do the welding out of my combustible fixture.

 The welding rod I used is Ni-99 TIG welding rod. Its basically pure nickel rod. It works great for small cast iron repair jobs like this.

Once the wheel was securely tacked I could get it out of the fixture. The sequence was gouge and tack until I had all the cracks prepped for the welding. By this time the wheel was pretty warm which is just what I wanted. No need for a preheat on these other than from the tack welding. I don't have any temp sticks but my calibrated bare hand told me the wheel was around 150F when I got to the main welding. Not hot but not cold either.

As you can see the welding came out pretty good. I managed to save a piece of history. Later on I'll grind and finish the surfaces where your hands contact the wheel. Other than that I don't think I'll fill and blend all the welds.

I did do some experimental video shooting on this job. My still camera shoots OK video so I figured I'd try it out. Please comment and let me know if you like the written stuff better than video or vise versa.

There are more video's in this series on my YouTube channel oxtoolco. Check them out. I still have some to upload.

Thanks for looking.