Skip to Content.
Sympa Menu

machinist - Re: [machinist] Drill bushing information.

machinist@lists.ibiblio.org

Subject: Machinist

List archive

Chronological Thread  
  • From: Lawrence London <lfljvenaura@gmail.com>
  • To: machinist@lists.ibiblio.org
  • Subject: Re: [machinist] Drill bushing information.
  • Date: Sun, 25 Oct 2015 23:08:30 -0400


On Sun, Oct 25, 2015 at 7:31 PM, Lawrence London <lfljvenaura@gmail.com> wrote:
https://www.carrlane.com/catalog/ind...2A36515F56455B

Bushing | Liner Installation Tips

Drill Bushing Information - All American Products Group

It's a start. I'm sure there's a lot more to it than this...

Quite a few PM threads as well:

Drill Bushings

Proper Use of Drill Bushings

Drill Jig Material

More feedback:

Don't be limited by what McMaster lists in their catalog. You can buy any style and any size that you need. Look at the catalog again and you should see "Also Available: Other sizes. . . ." Also, ACME has an on-line store.

Drill Bushings | Drill Bushing
http://www.acmeindustrial.com/precisionbushing.htm

The desired clearance depends on a number of factors. .0046" too sloppy for most applications, but it depends on what tools you're using and what tolerances you're trying to achieve. I'm guessing that your part is fundamentally esthetic in nature and the hole locations just have to be 'close'. I would recommend using bushings with about .0003" to .001" clearance to your tool. The lower clearance will allow for some thermal effects as things warm up. The higher clearance will allow for some misalignment/flex in your DP/fixture.

Obviously (to me), you need to use a bushing long enough so the major diameter of the tool (countersink OD) in guided before the drill point touches the work

I should have been more clear, you can buy ANY diameter (in .0001" increments) bushing you want specify. The cost for "non-standard" sizes is little more than standard/common/stock sizes. They just take the next smaller ID in stock and hone it to your size (and re-mark).

For 150 holes a month I'd do it in 2 ops, combi drill/csks are spendy and they don't clear stringy swarf well, and bronze is usually stringy and abrasive so tool wear is quite high.

Small drills require a fair turn of speed - my book says <> 1300 rpm for 3/16 @ 60ft/min.

Countersinks don't like speed! I'd shut that down to 500rpm or lower.

I'd go for a guided countersink, less chance of chatter, and a very quick op once set.





Archive powered by MHonArc 2.6.24.

Top of Page