Clubbed shop heads...again!!

[cjensen]

ok, i have squeezed these few rivets twice with the same results. the second pic is a little blurry, but the first one shows them pretty well. i can't get the pneu squeezer in there for some reason (i could on the other spar, but not this side ), and the clubbed heads are coming from my hand squeezer. i am being as steady as i possibly can...the one's on the bottom of the pic are set just right, but the top ones are clubbed.





i've had this issue before with this squeezer. i've squeezed good rivets with it before, but i CAN'T seem to set these correctly. i don't like drilling these out being on the spar...

so, should they get drilled again, or are they acceptable for holding platenuts on? if i drill 'em, i think the only other thing to try is to buck 'em...

[Wicked Stick]

From the looks of the pictures, I'd say leave them alone.
They are only holding on the plate nut. Once the screw gets inserted and you tighten it down, then the plate nut itself is acting as the structural part.

No worries Mate

[tshort]

Ditto what he said - they look fine. I would not mess with drilling them out as you'll make things worse and it ain't cheap to replace the spar!

Thomas
-8 wings

[jim_geo]

Exactly, the plate nut isn't going anywhere. The more I hear about the hassles with pneumatic squeezers the more I take what I was told to heart. "Buy yourself some avionics instead".

[captain_john]

OH! BTW...

I *think* I know the problem...

The flush set is riding down the nut plate and when it contactes the flare of the nut plate, it cants the rivet over.

Note, the clubbed rivet is in going away from the nut plate.

ALSO note, the nut plate on the right has a bite on it from the squeezer!

Soooo, here's whatcha do: Grind a flush set so it will fit into the location nicely. Basically you will need to zip off one side of the flush set.

Sorry I forgot to mention this earlier. Thermos just had the same problem and he borrowed my flush set that I used to do mine.

I will try to stay ahead of you from now on. Sorry, Chad!

CJ

[tshort]

I did those rivets with the thin nose yoke; put the flush set on the manufactured head and use the thin nose yoke to form the shop head. I didn't have any trouble getting in there.

Chad said he did those with his hand squeezer ... I have not had any trouble with my pneumatic squeezer and it is one my favorite tools ... no hassles at all!

Thomas
-8 wings

[cjensen]

totally agree thomas! (sorry jim! )i couldn't get my pneu squeezer in there for those for some reason...

CJ, strangely enough, i was using a modified c yoke and set...

anyway, it sounds like it's nothing to worry about since the structural strength comes from the screw.

[tshort]

Do you have a thin nose yoke? I get tons of use out of mine. It is far easier to get into some of those small spaces.

Incidentally, what hand squeezer do you guys have? I don't have one but was thinking of getting one for some of those rivets where it is tough to get the pneumatic squeezer in and balance everything...

Thomas

[captain_john]

Well then, Chad... this needs to be ironed out before you get too far along in the project.

Perhaps the problem is technique. Last time around you confirmed for us that the alignment if the yoke and the requisite rivet sets are in perfect alignment. This leaves operator error as a variable and I am guessing that your technique needs attention.

When you line up on the rivet be certain the travelling set's polished surface is sitting completely FLAT against the manufactured head. Also, perfectly in line with the length of the rivet.

I know this sounds simplistic in nature and is usually taken for granted, but I can't think of another reason for the clubbing.

Do you think it is technique?

CJ

[captain_john]

Oh, and Jim... Congrats on becoming Class Delta!!!

CJ

[cjensen]

my hand squeezer is a martin aircraft surplus.

it very well could be technique CJ, but i have to think it's the squeezer now. after looking at it's movement again with pressure being applied, i think the yoke's strength has been compromised by the removal of some of the nose area to fit in to tight places (it appears to be flexing, creating a non parallel movement). i'm always very aware of the squeezer being square to the work since i ruined all those rivets on the HS spar last summer. i actually couldn't believe what i was seeing yesterday while squeezing those 'cuz the squeezer was square left-right, fore-aft, and top-bottom

i don't have a thin nose yoke, but i'll get one. i need to get a longeron yoke anyway...maybe an adjustable set holder as well. washers seem to work fine, but i'd get more fine tuning out of the adjustable one.

SO, since we are talking about the spar, is the general consensus to leave 'em and avoid drilling the spar? i'll drill 'em if i need to, but i tend to agree that it's not structural in anyway.

[tshort]

I love my adjustable set (Avery) ; I have heard that the one from clearairtools.com is better:

http://clearairtools.com/Merchant2/merc ... y_Code=PRS

I would definitely leave those rivets as is.

Thomas
-8 wings

[captain_john]

Yes, I would agree about leaving them as it too.

CJ

[cjensen]

do you have do disassemble the pneu squeezer to install the adjustable set?

[tshort]

Nope-
When you take the yoke off it just drops in to replace the one that is there now. Quick and easy.

T.

[jim_geo]

So Chad am I understanding that what was happening is the rivet set was moving downward and sideways against the Conical nut portion of the plate nut?

[cjensen]

yep.

this morning i looked closer at the hand squeezer to see if it really was moving non parallel. i shaved some of the c yoke and the flush set to gain access to tight areas, and it seems to have allowed some flex that wasn't there previously. when i applied pressure, i can plainly see the yoke moving away.

maybe the pins that hold the yoke in place are moving a little from repeated removing to get dimple dies in and out??

that's the only thing i can think of.

[jim_geo]

Oh so the tool is flexing?

[cjensen]

i THINK that is what's happening. what i can't tell, is if the flex is coming from the yoke tip (meaning where the set is inserted) or from the base (where the three pins are holding the yoke to the squeezer).

i'm gonna run some more practice rivets, hopefully tonight, and i'll take pics to show you what i'm talking about.

[cjensen]

well, i didn't get to checking my hand squeezer...maybe tomorrow...