Lets talk runnout

[Kennyv]

(11-26-2015, 11:01 AM)PixMan Wrote: Also, what size range are these chucks and are they the "genuine article" made in USA (Jacobs) and Germany (Albrecht) chucks or the cheap knock-offs? Have you mounted the chucks on quality arbors or "import" quality ones?

Lastly, don't overthink this. If the drills being used were high performance solid carbide you need 0.0002" runout. With HSS jobber length drills, anything under .005" or so should be fine.

(11-26-2015, 12:54 PM)EdK Wrote:

(11-26-2015, 12:36 PM)johnnyc14 Wrote: ... I bought this Llambrich with a built in R8 arbor because they promise less than .0006" run out...

I also have Llambrich drill chucks and I've been very please with them for the money.

Ed

Very Nice drill  chucks there.... soon ill trade em up .and/ or replace.  They are of  decent  quality , so was the arbors i had tested  . Since Measuring  from the collet face/d fixed collet test., having good indication of radial runout. However  I suspect most  deviation was  due to poor  repeatability . I suspect was most likely  due to the angular component.  My best guess  you would have to expect this  with  a machine cost  under 5k   (CHINA MILL)

 Anyways  yea i was using decent arbors when originally running tests  . however i did note each time i had isolated removing potential variation due to fitting arbor,   run out became less however couldn't  believe .0025- .003 (2-3" down) where end of drill would be l as being acceptable .  guess need better equipotent    , soon right now its all for hobby. Who knows i may go To Virginia and take up living n   fishing again...

[Dr Stan]

I believe there is an underlying issue as many machinists expect a vertical mill with a DRO to be as accurate as a jig borer. Let's face it that's just not going to happen. Center drilling, drilling & reaming a hole on a mill will fairly accurately locate a hole, but it's not going to be within .0002" or so like with a jig borer. Larger holes can be bored which will improve the accuracy of the location, but will still not be of jig borer accuracy, unless one spends an insane amount of time and utilizes indicators with .0001" or tighter accuracy for the adjustments.

If you have parts that absolutely have to have very accurate hole locations one of the best ways to insure the accuracy is to drill & ream the holes with the parts assembled.

I've never expected a drill chuck to have an accuracy of .002" or less, in reality they typically have .005" or more run out like a 3 jaw chuck. Common wear & tear, spinning a drill bit, dropping it, and other issues reduce the accuracy of a drill chuck. Even more so when the chuck is used in a shop with multiple personnel.