countersink – PH-MNX http://ph-mnx.nl Building and Flying my π in the Sky Wed, 09 Jan 2019 20:10:58 +0000 en-US hourly 1 https://wordpress.org/?v=6.2.6 http://ph-mnx.nl/wp-content/uploads/sites/7/2023/01/cropped-maverick_150-32x32.png countersink – PH-MNX http://ph-mnx.nl 32 32 Aileron Dimple – Countersink http://ph-mnx.nl/2019/01/09/aileron-dimple-countersink/ http://ph-mnx.nl/2019/01/09/aileron-dimple-countersink/#respond Wed, 09 Jan 2019 20:10:58 +0000 http://ph-mnx.nl/?p=1440 I underestimated the amount of work with respect to deburring, scuffing, dimpling, countersinking, degreasing and priming. I thought I could do all this in one straight session. Especially priming is something I need to plan, because after that I can’t use the workshop for a few days (insufficient ventilation).
It took me more than double of what I expected for the Ailerons.

After deburring I use the Scotch brite pads to scuff the Aluminum, before dimpling. I specifically use this order to minimize the damage on the pads. You can only use them for one such a session, but scuffing without deburring will rip the pads apart quickly. Also scuffing after dimpling has similar effects, because the dimple rips the pad.

To dimple the skins, I really like the DRDT-2. According to some fellow builders the C-Frame is “better” because of the impact, but I don’t think Aluminum is affected that way. The DRDT-2 provides consistent dimples and is fast. Also if you give me a hammer, I might hit other stuff then just the plunger of the C-Frame.

I always check the other side if I got all holes. Sometimes I skip one (mostly due to printing on the blueing).

The same dimple sets that are used in the DRDT-2 can be used in the squeezer, with the same result. Due to the limited reach through the length of the yoke, this method is not applicable for skins. But stiffeners and ribs are easy dimpled this way. Ribs are almost impossible to dimple with the DRDT-2 because of the flanges.
The pneumatic squeezer is very versatile, because you can dimple and rivet with it. You have to be careful though, if you misfire it will punch holes in Aluminum of this thickness.

The narrow parts of the ribs are even for the squeezer unreachable. Here I use the dimple set with ordinary pliers. It’s really slow and cumbersome, but it is only a few holes that need this treatment.

The Spars and the doubler plates are too thick to dimple. It would distort, deform and probably damage the parts. Fortunately because of its thickness you can use the countersink drill (called machine countersink in the manual). Setting the depth of the drill once and then drill away.

Time: 5 Hours, Rivets: 0/0 (2019-01-09)
Time: 5 Hours, Rivets: 0/0 (2019-01-12)

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Wing Dimple & Countersink http://ph-mnx.nl/2018/10/07/wing-dimple-countersink/ http://ph-mnx.nl/2018/10/07/wing-dimple-countersink/#respond Sun, 07 Oct 2018 19:27:38 +0000 http://ph-mnx.nl/?p=1257 In between sealing and riveting Tanks, I took the time to dimple and countersink the wings. The main spar should NOT be dimpled, as the material thickness is to high.
It will either fail or you will damage the main spar.

Since the material is thick enough it is easy to countersink.
The ribs on the contrary can easily be dimpled. In this case with the every so beautiful squeezer. If you would try to countersink the ribs that would go horribly wrong because of the thin material.

The rear spar of the wing is a special case, the thickness of the Aluminum is somewhere between the ribs and the main spar. You can dimple it, but it will not be as “deep” as the rib dimple. So I do both dimple AND countersink the rear spar. Although the countersinking doesn’t take away that much material.

Afterwards I spot-primed all the countersunk holes. Again probably not necessary, but better save than sorry. Also on the Sunday I primed the leading edge skin and some trailing edge parts I forgot earlier.

Time: 5 Hours, Rivets: 0/0 (2018-10-03)
Time: 3 Hours, Rivets: 0/0 (2018-10-06)
Time: 3 Hours, Rivets: 47/0 (2018-10-07)

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