Reaming Aluminium

[Hugh GilhespieParticipant @hughgilhespie56163]

Hi, I’m having a problem reaming 4 mm holes in aluminium plate, 6061 grade I think.

I’m drilling to 3.8 mm at about 2500 rpm  then putting the 4 mm machine reamer through at about 1300 rpm with loads of WD40. The problem I get is chips stuck in the reamer flutes. I have to poke them out with a fine punch after each hole. I have tried using the reamer at slower and faster speeds but still the same problem. The holes seem to come out OK as I get a nice sliding fit with a 4mm dowel pin but having to clean the reamer each time doesn’t seem right.

 

What am I doing wrong? Initial hole size? Speed? Whatever?

[Hugh GilhespieParticipant @hughgilhespie56163]

[JasonBModerator @jasonb]

Sounds a lot too fast to me, I would run the reamer at 50-100rpm and prefer parafin to WD40. Also a 3.9mm would give the reamer less to remove so not such a high chance of the swarf build up

 

Jason

[Sub MandrelParticipant @submandrel]

10 thou doesn’t seem too heavy a cut for aluminum – that’s Humphrey Davey’s original spelling

 

I would use neat cutting oil or paraffin and go slower though as Jason suggests, but aluminium swarf seems to clog as a matter of course

 

But if the holes are OK and the aluminium isn’t actually welding to the reamer, I wouldn’t lose sleep.

 

Neil

[Tore NilssonParticipant @torenilsson76190]

Use methylated spirit as lubricant, and probably 100 rpm, and don’t smoke then you are doing it. You can dilute the metho with water if you want  2part metho/1 part water.

 

Tore

[Richard ParsonsParticipant @richardparsons61721]

 

Hi   

Have a look at the thread called ‘The use of adjustable reamers’ I think you will find the answer to your problems.  Remembers reamers are really scrapers and are greedy beasts.  Aluminium can be sticky stuff and will clog the blades so do not try to take out too much. When compressed, the swaff, can become harder that the metal it came from. This would leave a rough surface.

 

 

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