How do you drill out the 582 lord mounts on a mod IV?

[beeryboats]

Hi guys, I received my new lord mounts and I'm trying to drill them out to 5/16" from 1/4". I have a brand new drill bit and I'm barely starting to make a dimple. I'm afraid to push too hard and blow the center out of the mount. I could try to back it up with a piece of wood, but I'm still scared I may twist the center loose. How did everyone else do this chore? I'm about to take it to a machine shop.
Thanks,
Jay

[jrevens]

Jay,

I'm sure others will chime in if I'm wrong, but if you're talking about mounts that are rubber molded to a thick steel washer, the washer is hardened steel. When you drill it you need to apply adequate pressure & lubricant with the proper sharp bit to cut. If you are too light on the drilling pressure all you do is heat the steel in that small area, making it even harder and more difficult to drill. You might even need a carbide drill bit now. If it's a rubber mount molded around a steel bushing, I don't think you want to drill it out - need to buy the right size mount.

[beeryboats]

It's the bushing molded into the rubber mount. And from what I hear, drilling out the center is the proper mod to make it work. Mine are old and at least one is drilled off center.

[jrevens]

I'm glad you got your answer on the other thread, Jay. I was in the process of composing a reply that you not try to do it all in one cut, but go up 1/64" at a time, when someone who knew what he was talking about pointed you in the right direction. Good luck!

[Dusty]

They are next to impossible to drill without damaging the rubber just use smaller bolts and sleeve the bearer with a bit of moly tube

[beeryboats]

I got two done at lunch with our fancy drill press. I say fancy as it's almost a milling machine with its adjustable bed. I just stepped up the drill sizes until I hit 5/16". The first one was close to center and the second one was dead on. I used window cleaner as a coolant, it was handy, and did no damage to the rubber. Just gotta go slow and steady. I hope to get the other two done tomorrow.

[Av8r_Sed]

Never heard of window cleaner as a coolant, but glad it's working out. Like most of these things, once you learn the trick you wonder why it seemed hard.

[beeryboats]

I got the other two drilled dead on center today. The window cleaner was the only water based spray I had on hand. Oil is hard on rubber, so I used the window cleaner. Works great!