Countersinking

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AaronG
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Location: Dallas-Fort Worth Area

Countersinking

Post by AaronG »

Before doing some of the initial countersinking with the micro-stop tool, I have been practicing on some test material ( to get the depth right for the #30 120 degree cutter.

For consistency, have others used a drill press where possible rather than a hand drill with the micro-stop tool? Also is there a particular target RPM that yields the most consistent countersunk holes from your experience?
ebrunye
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Location: San Diego

Re: Countersinking

Post by ebrunye »

Different materials countersink differently, but I have done all the countersinking with my hand drill set to the faster speed. The micro stop tool does a good job of keeping the countersinks round. Are you preparing to countersink your main spars or what? I was able to countersink my main spars, seat rails (plastic and metal), and all the nutplate locations no problem just by hand. A few places, such as the gas tank caps, have a lip that makes you unable to use the whole micro-stop tool. For these holes, I take off the stop part of the tool and just use the countersink bit and the holder for it, and attach that to the drill press. Then you can adjust the stop on your drill press to keep the appropriate depth and squareness.
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PhilipRueker
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Re: Countersinking

Post by PhilipRueker »

AaronG wrote: Wed Dec 18, 2019 9:40 am For consistency, have others used a drill press where possible rather than a hand drill with the micro-stop tool? Also is there a particular target RPM that yields the most consistent countersunk holes from your experience?
I don't have a drill press, so I just do all of them with my hand drill and the micro-stop (unless the micro stop can't be used as Evan mentioned in some rare cases).

As for RPM - generally speaking you want high RPM for a quick and clean process for both countersinking, as well as drilling in general.
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Caddy1820
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Re: Countersinking

Post by Caddy1820 »

Have you guys had problems with the holes turning oblong while countersinking? I am using high speed and a micro stop but the pilot holes are getting ovaled. Not sure what I’m doing wrong.
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PhilipRueker
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Re: Countersinking

Post by PhilipRueker »

Caddy1820 wrote: Sun Dec 12, 2021 6:06 pm Have you guys had problems with the holes turning oblong while countersinking? I am using high speed and a micro stop but the pilot holes are getting ovaled. Not sure what I’m doing wrong.
You need to make sure you have the stop calibrated correctly with the micro-stop, then if you are correctly straight, it should yield a nice and round countersunk hole.
You have to be careful that you're not angled and nice and straight down, or that may yield uneven results that might be what is leading to your oval holes.
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Caddy1820
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Re: Countersinking

Post by Caddy1820 »

Thanks for the advice. What ended up working for me is putting another piece underneath it so the pilot part of the bit has more surface area. I’m thinking I should not have to do that for the spars as they are a lot thicker.
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ibgarrett
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Re: Countersinking

Post by ibgarrett »

What I found that worked for me was to ease the bit into the calibrated micro-stop bit slowly into the hole at a slight angle. If I tried going straight down I almost inevitably had a wonky hole. If I had an angle and slowly eased into the hole it would be perfect every time.

It's a little hard to tell because of the time lapse, but this is where I discussed it at when I drilled mine out -
Brian Garrett
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