|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

02-05-2017, 08:47 AM
|
 |
|
|
Join Date: Feb 2005
Location: Westland, MI
Posts: 311
|
|
Jagged Countersinks
I know I've seen a thread or two on this before, but the search didn't turn up the threads.
I am countersinking some holes in a piece of aluminum on a different airplane and they are coming out really jagged.
In the pic you will see the jagged hole, and the other hole I've smoothed out with the hand held debur tool.
But I've used the bit shown on the RV-7 and all the holes came out absolutely smooth and perfect.
What's going on now? Is the bit dull? I've tried high speed and low speed and the speed makes no difference. I've tried light pressure and high pressure and they all come out jagged. I can smooth them with the debur tool, but I'd rather them just come out smooth from the countersink tool!
Any thoughts?
Thanks

|

02-05-2017, 08:53 AM
|
|
|
|
Join Date: May 2012
Location: Harrisburg, Pa
Posts: 759
|
|
Generally when I've had chattering while counter sinking it has been when I'm not properly backing up the work piece. This allows the pilot to wander causing the results you're seeing.
|

02-05-2017, 08:55 AM
|
 |
|
|
Join Date: Feb 2005
Location: Westland, MI
Posts: 311
|
|
I don't think that's the case here as I have two pieces of wood underneath the hole right up to the hole. So it's pretty solid under.
|

02-05-2017, 09:36 AM
|
|
|
|
Join Date: Apr 2009
Location: Stockton, California
Posts: 296
|
|
Advise you look at the cutting edges with a loupe or inspection microscope?
|

02-05-2017, 09:44 AM
|
|
|
|
Join Date: Oct 2005
Posts: 1,516
|
|
Single flute
These single flute countersinks produced better results for me.
http://www.cleavelandtool.com/Single.../#.WJdVxlu8Zao
__________________
Ernst Freitag
RV-8 finished (sold)
RV-10 Flyer 600 plus hours
Running on E10 mogas
Don't believe everything you know.
|

02-05-2017, 10:02 AM
|
|
|
|
Join Date: May 2012
Location: Harrisburg, Pa
Posts: 759
|
|
Quote:
Originally Posted by s10sakota
I don't think that's the case here as I have two pieces of wood underneath the hole right up to the hole. So it's pretty solid under.
|
You know, right after I posted that, I looked at your signature and assumed you had covered that base  . If every hole does it with that cutter, I would guess the cutter...
|

02-05-2017, 10:37 AM
|
|
|
|
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,435
|
|
Quote:
Originally Posted by s10sakota
I don't think that's the case here as I have two pieces of wood underneath the hole right up to the hole. So it's pretty solid under.
|
Try a piece of 1/8" aluminum instead. That worked for me. I'd let the countersink go into the aluminum, which was thick enough that the pilot remained constrained.
I use a very low speed for countersinking. I use a Dewalt battery drill.
The 1/8" aluminum part had other holes in it so that I could cleco it to the work using adjacent holes.
Dave
|

02-05-2017, 11:03 AM
|
|
|
|
Join Date: May 2012
Location: Harrisburg, Pa
Posts: 759
|
|
Quote:
Originally Posted by David Paule
Try a piece of 1/8" aluminum instead. That worked for me. I'd let the countersink go into the aluminum, which was thick enough that the pilot remained constrained.
I use a very low speed for countersinking. I use a Dewalt battery drill.
The 1/8" aluminum part had other holes in it so that I could cleco it to the work using adjacent holes.
Dave
|
Same technique here - start very slowly and end fast once I know the cut has been initiated smoothly; always use the electric for this. Good call on using aluminum to back up the work. If countersinking a lot and using wood, I usually have to make a fresh hole fairly often as the hole quickly gets slightly enlarged and doesn't hold the pilot as well as necessary.
|

02-05-2017, 11:14 AM
|
 |
|
|
Join Date: Apr 2011
Location: Cincinnati, OH
Posts: 2,791
|
|
Quote:
Originally Posted by N427EF
|
ditto, these worked much better for me.
you owe it to yourself to try one of these debur tools, you will never go back
http://www.cleavelandtool.com/Deburr.../#.WJds29QrKys
__________________
Steve Melton
Cincinnati, OH
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 800+ for all
Simplicity is the art in design.
My Artwork is freely given and published and cannot be patented.
www.rvplasticparts.com
Last edited by Steve Melton : 02-05-2017 at 11:21 AM.
|

02-05-2017, 11:19 AM
|
 |
|
|
Join Date: Aug 2009
Location: Southern California
Posts: 882
|
|
Chatter
Quote:
Originally Posted by s10sakota
I know I've seen a thread or two on this before, but the search didn't turn up the threads.
I am countersinking some holes in a piece of aluminum on a different airplane and they are coming out really jagged.
In the pic you will see the jagged hole, and the other hole I've smoothed out with the hand held debur tool.
But I've used the bit shown on the RV-7 and all the holes came out absolutely smooth and perfect.
What's going on now? Is the bit dull? I've tried high speed and low speed and the speed makes no difference. I've tried light pressure and high pressure and they all come out jagged. I can smooth them with the debur tool, but I'd rather them just come out smooth from the countersink tool!
Any thoughts?
Thanks

|
Chatter is often the result of a combination of too high of a tool speed combined with too little cutting pressure. If you are already backing up your work with a piece of metal or wood, match drilled and rigidly clamped, then I would suggest using more pressure on the drill. Also pull the cutter off of the hole as soon as it bottoms against the stop.
Skylor
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 03:10 AM.
|