MadModder

The Shop => Tools => Topic started by: kayzed1 on February 25, 2015, 04:30:22 PM

Title: Chester 626 help.
Post by: kayzed1 on February 25, 2015, 04:30:22 PM

Hi gang, can some body help please?
Today i was going to chain drill a row of 6mm holes before i milled it 7mm for around 30mm long, any way as i pulled on the arm to prescient the drill bill the  mill sounded like a high speed hammer drill on full chat....so i stopped..any ideas please. I did drill the holes very slowly...
Lyn.

Title: Re: Chester 626 help.
Post by: Joules on February 25, 2015, 04:45:08 PM

Take the drive belt off and rotate the spindle by hand and tell us what it feels like.  Smooth/Lumpy, also push and pull the spindle to see if there is any movement or knock.  Whilst your at it run the motor briefly to make sure that isn't causing the problem.

Title: Re: Chester 626 help.
Post by: velocette on February 26, 2015, 12:27:01 PM

Hi Lyn
what were the chips like coming off the material short and flaky then the drill is not sharpened correctly add that to speed too slow with not enough downward force then the noise is probably the drill bit chattering in the cut instead of removing a continuous  curled chip.

A spindle speed about 1500 RPM in mild steel is a ball park figure as a guide.
REM Feet per minute cutting speed / drill dia * 3.1416 = rpm cutting speed.
Eric
 

Title: Re: Chester 626 help.
Post by: mfletch on February 26, 2015, 12:45:13 PM

 or even work peace not tight so coursing chatter

Title: Re: Chester 626 help.
Post by: kayzed1 on February 26, 2015, 04:21:39 PM

Thanks for your replies chaps, i did check the belts and pulleys today along with the full movement on the quill and no play any where...Re: drill bit..I chucked a 10 pack in the bin a few days ago as not one was parallel....one of those impulse buys from the net 10 drill bits very cheap..
I will have another look/play tomorrow.
PS: collet was done up ok along with the mill vice so only leaves the drill bit :doh:
more anon.. 
Lyn.

Title: Re: Chester 626 help.
Post by: Joules on February 26, 2015, 04:53:27 PM

Glad it was chatter and not a broken spindle bearing.  I didn't even think about chatter for some reason  :scratch:

Pick up a drill grinding jig, they are pretty cheap and quite effective.

(http://s1.hubimg.com/u/3646514_f260.jpg)

Can turn crap drills into something workable.