Spring Landing Gear

[SWeidemann]

I like the advice about taking the gear to a good machine shop to do a straight hole. Question is however, just how far away from the edge is the gun drilled brake line channel?

At a minimum, I would support the gear in a drill vise and carefully mark and drill the holes that way. Start with a smaller pilot drill and work your way up. Don't do it by hand.

Having said that, I can also say that sometimes despite all my efforts a drill will still sometimes wander off center. Even a pilot hole may not be enough if the drill finds some "grain" in the metal. When I drilled the gear legs for my BD-4 I made a jig out of steel and then used the jig to drill the holes. Even then the holes needed some light reaming to get all four bolts through.

If you have any doubts, let a good shop do it.

FWIW,

Mark Napier

[SkyPirate]

Without actually seeing it i would put them inboard close to the inboard side of gear bolt

[SkyPirate]

Center your gear, take a 5/16" center punch put it right up against the inboard side of bolt, center up and down an set a dimple, if you use a 1/4" center punch, i would think it would be too tight and flex in the gear would eventually bend the dowel pin and wear on the bolt

[SkyPirate]

Again without looking, if it is gundrilled, there should be a hex bung on the very bottom of the gear leg, check its orientaion if its centered or more toward front or back, the gear is tappered, evenly tappered bothe front and back or straight front and tappered back, if its evenly tappered, measure to center of hex bung plug, from the opposite side of brake lines, then measure width at bottom front to rear, then measure widest part of gear at fuselage front to back, check difference on opposite side of gun drill

[SkyPirate]

If your taking the gear completely off you can remove the brake fittings and check depth of holes under the fuselage, subtract that from width of gear, you should have plenty of room to put a 1/2 deep hole on the opposite side but better safe the sorry

[SWeidemann]

Excellent suggestion. Thanks

If your taking the gear completely off you can remove the brake fittings and check depth of holes under the fuselage, subtract that from width of gear, you should have plenty of room to put a 1/2 deep hole on the opposite side but better safe the sorry

[HighWing]

I had Hammerhead gear on my first Model IV. Check the bottom of the gear leg. there should be a fitting or plug where the drill entered. If the hole is centered on the bottom it should be centered through the leg. They are drilled in a fixture before bending much like center drilling on a lathe. After drilling for the brake line, the gear leg is bent and then heat treated.

Another thought. Where you will be drilling is a high stress area on the gear leg. Don't drill too deep.

[SWeidemann]

I was told by a staffer at Grove that my gear is a Hammerhead because all Grove gear has drilled holes with pins. Apparently Hammerhead was an earlier supplier.

Skot

I had Hammerhead gear on my first Model IV. Check the bottom of the gear leg. there should be a fitting or plug where the drill entered. If the hole is centered on the bottom it should be centered through the leg. They are drilled in a fixture before bending much like center drilling on a lathe. After drilling for the brake line, the gear leg is bent and then heat treated.

Another thought. Where you will be drilling is a high stress area on the gear leg. Don't drill too deep.

[Av8r3400]

I just sold my early, non drilled, Grove gear to another member on this board. They did make them that way.

[desertfox1]

I'm a little confused, are we talking about gun drilling for the
brake line or hole drilling for the locator roll pins?

Phil