drill bushings

[jlnak907]

i was given an assortment of misc machinist tools and in these was a hole bunch of precise bushings that were made to exact diameters, after researching for a long time i found out they mere called drill bushings i have all different sizes from one inch to .25 these also have inserts, my question was is if anyone on this forum has heard of these and what exactly there used for, i know there used for some type of machine work i was just curious though,thanks for any information you can give

 

[Old Iron]

The drill bushing go in a fixture to get precise hole layout for drilling, The bushings are the right size for the drill bit usually use in a production set up. So anybody could get the wholes i the right place.

I have a few I got somewhere don't figure I'll ever use them in my home shop.

Paul

 

[Tony Wells]

There are master bushings that are pressed into a jig/fixture plate, and insert bushings. Both are hardened and ground. The master bushing is not used to control the drill directly. (There are press in bushings designed for drilling though)The insert bushing fits closely in the master bushing, some with a quarter turn lock notch. This accomplishes couple of things. First, when the insert bushing wears, you toss it and get a new one. Second, it allows different sized insert bushings to be used in the master bushing so different drill can be used in the same location, for stepped holes. These days, with CNC machines, there isn't a large demand for these bushings, but they do have their place. You can do mill accurate hole placement on a drill press if you have a drill jig, and once the jig is proven, it's tough to put a hole in the wrong place.

 

[Kevin45]

i was given an assortment of misc machinist tools and in these was a hole bunch of precise bushings that were made to exact diameters, after researching for a long time i found out they mere called drill bushings i have all different sizes from one inch to .25 these also have inserts, my question was is if anyone on this forum has heard of these and what exactly there used for, i know there used for some type of machine work i was just curious though,thanks for any information you can give

It sounds like you have an assortment of bushings. You can have a press fit headless bushing. This bushing normally has a thicker wall to it. Then you could have a press fit liner. This will look like your standard bushing but it may have a thinner wall. Then you have a headed press fit bushing. This is just what the name implies. It is like your standard press fit bushing but with a head all around. Then you may have a Slip fit renewable bushing. This will have a knurling around the head of the bushing along with a semi-circular cutout on the side of the head and a recessed area. This is so you can drop it into a liner, turn it, and lock it into a screw. Some liners and pressfit headless can look the same, but you should be able to tell if there is a number on there. The numbers are ANSI standard numbers