Belly Screws

[acronut]

So we recently purchased a 67 M20F that had gotten a fresh paint job.  I've been wondering how I was going to remove all the belly pan screws that were mostly fulll of paint.  I thought I would end up having to grind the heads off of many of them to remove them.  I've worked on a lot of aircraft and built a lot of things and never had much luck with any of the gimic tools.  Well today I found a tool and decided to give it a try.  I bought a Craftsman impact driver and figured it would be a waste of $99.00.  All I can say it that it payed for itself today and I'm pretty sure it's only begun to see it's full use!  It works great and lets you apply a lot of pressure onto the screw while it hammers it out.  I ended up only stripping out 3 of the screws and then I fugured out an easy way to remove those as well.  I simply made a new slot in the screws with my dremmel tool and used a straigt screwdriver for a good solid grip.  Worked way better than I could of imagined.  Hope these tips might help someone else out sometime.

Kendal

 

[thinwing]

hey acronut..thanks for the tool report...I will add the impact driver to my tool chest.Yes grinding a slot on screw heads really works...but,try that trick on a countersunk screwhead...ouch!!I use an old dentists airpowered drill for the countersunk screws...sinc kp couch

[KSMooniac]

You should purchase a bunch of replacement screws to fit the belly panels and other inspection panels and just keep them handy when working on the plane...sooner or later you'll need them!  Ditto for some tinnerman nuts.

[HopePilot]

I have an annual coming up in a month.  Would you recommend getting some of these:

http://www.ddaircraft.com/sskits.cfm or is there a more flush replacement?

[N9937c]

When you run across a screw that the drive is rounded just chuck up a LEFT handed drill bit. Start slow and when the drill point is engaged fully apply more force. The screw will spin out

larry

[acronut]

Quote: KSMooniac

You should purchase a bunch of replacement screws to fit the belly panels and other inspection panels and just keep them handy when working on the plane...sooner or later you'll need them!  Ditto for some tinnerman nuts.

[Sabremech]

Some tricks to get screws out. Clean any paint out of the screw head. Use a speedhandle to break them loose. Use some valve grinding compound on the tip of the bit for tough screws. If all else fails get a set of easy outs. I'd only use power tools once the screws are broken loose. You will end up replacing less screws if you hold off on the cordless drills and impacts.

 David

[acronut]

Quote: Sabremech

Some tricks to get screws out. Clean any paint out of the screw head. Use a speedhandle to break them loose. Use some valve grinding compound on the tip of the bit for tough screws. If all else fails get a set of easy outs. I'd only use power tools once the screws are broken loose. You will end up replacing less screws if you hold off on the cordless drills and impacts.

 David

[acronut]

Quote: HopePilot

I have an annual coming up in a month.  Would you recommend getting some of these:

http://www.ddaircraft.com/sskits.cfm or is there a more flush replacement?

[carusoam]

In My M20C, I found replacing the oriiginal hardware with SS screws made them easy to remove on the following year (or as required).  Hand turning the first 1/4 on each fastener is a must for non SS.  Not so critical once replaced with SS.  On the M20R, they are all SS already...whatever happened to the windy dissimilar metals debate?

Replacing many tinnerman nuts with matching (non-pointy) sheet metal screws will make life easier the next time around also.  It seams the springy nature of the tinnermans gets lost over thirty plus years.

Rule #1 on replacement.  If the screw driver slips the least bit on removal, toss the screw and replace with new.  Reminder: Get new driver tips.  Slipping out of the screw head may lead to a dissapointing paint scratch.

Belly screws are not all the same size.  Check the manual and you may find that a few are smaller diameter than others.

When putting all this stuff back:  Hold the panels in place with a few screws at first.  Don't tighten any until all screws are in place.  This will help position the sheet metal properly.  If you were to start tightening screws in one place and move your way around, each hole gets more in more out of alignment.  When this happens, loosen them all back up and devise a new "cross the sheet" tightening pattern.

1/4 turn fastener cores (camlocs and dzus) are easy to exchange with SS pieces.  camlocs require a special pliers to make a simple replacement.  (pliers are available with the cores)  Core sizes also can vary in length on the cowling (check your manual)

When re-using screws: clean by leaving in bag with oil or WD-40, set on paper towel to dry.  The're not really that dirty, if they are....toss as required.

Overall, old rusty fasteners can leave you heavy hearted on the ramp....One stripped screw or camloc can keep you from gaining the access that you would really like to have.

Best regards,

-a-

PS.  Stripped out truss head screws can actually be grabbed with a very small grippy pair of plyers available from the tool truck that stops by the airport.  One of the best things I learned from working with my A&P.  See Snapon.com.  This tool can also grab whatever is left after you are done left hand drilling, easy outing or just plain ripping the head off of a fastener....

[Hank]

Just measure the screws you want to replace, and order a bag of 100 from Spruce. If memory serves, there is mostly one size on my one-piece belly, except for some little ones behind the front wheel, and a different size for the wing panels. Some go into struts, some tinnermans. I bought two sizes of SS screws [100 ea], and the smallest bag of tinnermans that they carry, in time for the '09 annual. Ran about $50. Any screw I don't like on removal is thrown away.

At re-install, I start at one end and put screws in about every fourth or fifth hole, alternating sides the ful length. Use a small pick to get everything lined up for the screw. Then I remove the support, run these screws about halfway in, put in the rest about halfway. Run every 3rd or 4th one until it touches, alternating sides, then touch all of them. Then alternate again snugging them up, then finish snugging. Don't forget to recheck, as I've found one of the 52 belly screws sometimes gets missed . . .

Panels are similar but much easier. With the tinnermans, the pick is even more important. Work the star pattern like on your tires, there's just more screws. Start, seat, snug, check.

Do I want Bill Wheat's new one-piece belly with cam-locks? You bet! Am I prepared to pay 3 AMU's plus crating, shipping and install labor on the cam lock kit? Not any time soon . . . But I'm getting faster removing and replacing the belly, and I use a simply Craftsman replacable tip screwdriver, with a standard #2 Phillips on standby for the stubborn ones. It's a good forrearm workout, but at least I'm not doing it in July any more!

[richardheitzman]

the best advice I have seen is REPLACE OLD HARDWARE. Screws wear out. When you are putting them in, spray with a little CPC and in they go. Next time you pull them out, they will come out a lot easier. Mouse milk is a nice compond to have handy, it will "creep" up and into threads to help loosen up old hardware for removal.

"impact" wrenches and sheet metal do not go well together. The speedhandle, valve grit, vice grip method will not cause any secondary damage. "painted" screws should be cleared out by taking a pick for the screw head and running a razer blade around the outside. It will also save your paint from chipping and peeling away from the screw area.

[MooneyMitch]

"So we recently purchased a 67 M20F that had gotten a fresh paint job.  I've been wondering how I was going to remove all the belly pan screws that were mostly fulll of paint."

I realize this is after the fact for those that have already had their Mooney painted.  For those contemplating having your airplane painted, with my experience, I removed or requested that the paint shop, remove all panels or covers that were fastened with screws.  All these covers/panels were then painted individually and installled after the aircraft was painted.

This action prevents any paint chipping screw removal at a later date.  So far, so good.