Drill bit type

[lawnmowerman1960]

Hi all. Just joined the forum. Been following it for a time but this is my first time posting. I'm 59 and have wanted a Cub since I was little. I recently bought a 49 that is pretty much all there but needs repainted. I need some advice about what type of 5/32 drill bit to use so I can retap the 10-24 screw holes on the right side above the steering side of the tractor so i can reattach the dog leg.It will have to be a long shaft bit, but i need a recomendation on type and flute angle. Screws appear to be twisted off and may be stainless, not sure. Thanks again.

[Barnyard]

Welcome to the forum. Here is a link to a how to on your subject. viewtopic.php?f=147&t=44710

[lawnmowerman1960]

Thanks for the info. It appears someone before me had tried to drill the holes to no avail. I'm going to need a hard bit. What kind is best?

[MiCarl]

I've had good luck with cobalt drills in hard materials, although I've never tried them in cast iron.

[mozer71]

For starting, a "center drill" may work best. It is very stout without flex. They are two ended and short with a larger middle shank than regular drill bits. They are primarily used on lathes to establish a concentric hole. The tip may only go 1/8" deep but they continue cutting a 60 * camphor, the size of the shank. From that, larger drills can be located correctly.

[Nelson 634]

If you genuinely beleive it is a stainless steel machine screw, slow speed of drill motor, sharp bit, lots of lubrication (thinner is better)and chuck the bit up short. (Bit doesn't bend or break.) Do not get stainless hot it work hardens. Go Slow.

[lawnmowerman1960]

Thanks. I'm not really sure at this point. I have tried to drill the front hole on the front right hand side, but the bit doesn't seem to faze it. The one in back I can't get to with a short shank bit because of the casting clearance of the steering. So I'm thinking, try a smaller pilot hole first, then the tap size next. The holes have been boogered which make it even harder. I've only got one shot at this. The other side is fine.

[Rick Spivey]

It's more work, and a replacement casting might be easier in the long run. But when the area around the hole was messed up to the point we couldn't just re-tap the hole, then sometimes we would install a much larger repair plug, drill and insert a pin into the threaded portion (will keep repair plug from ever backing out), then drill and tap in that plug back to the original size hole in the original location. Not sure if a bolster lends itself to that, and you may need to use a thread sealant as well, since you likely will drill through into the water jacket. This may not be a good place for that kind of repair, but just thought I'd mention it.

[lawnmowerman1960]

I'm semi retired but work part time at one of the big box lumber stores. We sell short titanium bits that have 1/4 hex shanks and we also have a 6 in extension. I think I may have found what I need. Fingers crossed. I'm on vacation next week so I won't get to till the following week but I'll keep you guys posted.

[Matt Kirsch]

Another possible solution that I found at the (blue) big box store is a small diameter diamond hole saw. The hole saw is used to drill around the broken off screw, leaving a larger hole that can be filled with a larger bolt, or an insert to bring the hole back down to original size.

Worked great to drill around the snapped off bolt extractor I had, saved from having to pull the tractor apart and replace the casting, or take it to a machine shop and pay big bucks for EDM.

[lawnmowerman1960]

I never thought of that. We sell them here at our non blue store as well. Thanks.

[mozer71]

Sterling information, Matt.
Rick and everyone. Pleasure in this knowledge.