Practical Ideas

Practical Ideas

From the pages of PracticalMachinist.com

Boring bushings
While boring long bushings, do you ever find that the I.D. is just a hair undersize and you don’t want to make another pass for fear of making it oversize? In this situation, I cut a slot in an old broom handle or aluminum rod and wrap abrasive paper in the direction the machine’s spindle rotates. I insert this tool into the bore to sand it to proper finished size.

DrillDrill sharpening blues
After handsharpening drills, I often have the problem of them cutting with only one of their two flutes and drilling oversize. When this happens, I apply bluing to both cutting edges, drill a little more, remove the drill and check the edges. The edge that’s heavy will have no bluing on it, so I regrind that side, re-blue both edges again and repeat the procedure until the bluing wears off evenly on both cutting edges.

BearingsInstalling bearings
Before repacking and installing bearings, do not “whiz” the bearing (making a sirenlike noise) using compressed air. This ruins a bearing faster than running it dry at high speeds. Instead, after rinsing the bearing in clean solvent, blow it out across its surface while holding both races together. Then, apply grease and slowly roll the races, balls, rollers and cages around to ensure all surfaces are coated.

When installing, do not use brass or aluminum to drive on the races because small slivers may chip off and work their way into the bearing. A better choice is a piece of mild steel stock, such as keystock, that is tough enough to take the pounding but soft enough not to harm the bearing races. Finally, run in the bearings so the balls and rollers can roll and form a track, instead of just skating around.

Removing bearings
To remove an outer race from a bearing in a blind or semi-blind hole, I grab the welder. With the inner race and balls gone, I run a bead of weld around the inside of the outer race, let it cool and it usually falls out when turned over. Be careful not to weld the race to the housing.

Paper on edgefinding
To quickly and easily edgefind a part without having to remove the cutter from the machine’s spindle, I creep the cutter up close to the workpiece or vice and slip a piece of paper between it and the rotating cutter. I then hold the paper in place, making sure my hand is a safe distance from the cutter, and slowly feed in the cutter until it tears the paper away. Once that happens, I raise the machine’s quill and move in a distance of half the cutter diameter and set the machine’s readout to zero.

Idea gears up for workholding
GearI hold odd-shaped (out-ofsquare) parts for machining using sections of gears. To prepare these sections, I cut a 6-in.- diameter, 0.750-in.-thick gear in half and machine down the flats about an inch on each side, so when I mesh the gear teeth together, the two flats become adjustable.

In operation, I mount the good/straight side of a part against the fixed jaw of my vice and the meshed gear on the opposite side so it adjusts to the part’s shape. This idea works well on relatively severe angles, but I recommend taking it easy when cutting.

Another option is to substitute one of the round gear sections with a piece of rack gear and bolt it to the back jaw of the vice if possible.

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