Making small brass sleeve bearings with a Smithy - Plse help me improve my technique

I think I'd add a step right after step one; use your cutting tool to locate (and cut into) the center of the brass stock as far as you safely can. Then start drilling with your drill bit. I think there will be a little less 'wander' that way.

First, use a centre drill. Next, drill from both ends.

Does it start on-centre, then wander, or is it off-centre at the start?

-- Jeff R.

Use a screw machine bit which is shorter and stiffer than a jobber's length drill bit. Run the machine at its fastest speed and clear the chips often, using a hunt/peck motion. The idea of drilling starting with a center drill and going from both ends also has merit. If your hole were larger I'd recommend drilling undersize and then boring but I can't imagine a boring bar that can bore a 1/8" hole 1" deep.

This is tricky country, you are boring 800% of the diameter of the drill. Is there any chance you could get away with using two identical pieces each 1/2" long?

GWE

As Grant says, you are way beyond the definition of "deep hole drilling". Deep holes are usu. always difficult to maintain center. Use a center drill to start, and then a stub length drill (screw machine drill) for the hole. Good idea to center up and drill from both ends, also. Best results can be obtained by drilling under size and reaming to finish. Another thought is to use larger stock, say 5/16; drill, ream and then insert a mandrel of some sort into the bore and turn the OD down to 1/4.

Bob Swinney

What everyone said and bronze generally makes a better sleeve bearing than brass.

Bearing bronze; or even oil impregnated bronze, oil lite or something similar. A good hardware store is your friend.

Bob Swinney

Other replies are good, but have you verified that the lathe chuck is holding the

1/4" rod on center? If not, then any hope of getting the ID and OD concentric will fail. Do you have a dial indicator or dial test indicator? Check the OD of the rod as you rotate the chuck by hand. If no change, then you are fine. If there is a change in reading, then 1/2 of the max to min reading is the amount of eccentricity. Depending on your needs, you can decide if this is too much or OK.

To get the most accurately centered hole, you normally have to bore them, but boring a 1/8" hole would be a major pain. A reamer can make sure it is straight and free of taper, but it won't do anything for concentricity.

Jon

I would probably try and bore it for the first 1/8", then use a D bit to drill the rest of the way. Proper gun drills are (in my mind anyway) basically an outgrowth of the D bit. Lots of pecking: during the drilling only proceed about 1/16" per cut, then clear chips and add coolant.

Adam Smith Midland, ON

Lots of good sugestions, but as far as keeping your drill bit from starting off center, put a piece of stock in the tool holder very close to the brass you are drilling as a brace. Feed this brace against the drill bit (as close as you can to the tip of the drill bit) to push it just a few thou off center. Start feeding the drill bit into the brass and slowly back off the brace. If its not perfect, back the bit off a bit, feed the brace to deflect the drill bit again, and retry. You can get it so there is no perceptable wobble. Its quick, works well, and all you need is the standard drill and a piece of scrap.

Wayne Sippola, Moose Jaw