Hardened screw holes
#1
Senior Member
Thread Starter
My Feedback: (9)
Join Date: Apr 2003
Location: Manvel,
TX
Posts: 1,337
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
To harden the threads in hardwood servo mounting blocks or wing mounting blocks, drill the screw hole, install the screw or tap the hole, remove the screw and put a drop or two of thin ca in the hole and you now have a hardened thread. In the case of wing mounting blocks, you may need to re-tap the threads after you ca the threads.
Tom
Tom
#2
![](/forum/images/badges/premium_member.png)
My Feedback: (1)
Join Date: Mar 2003
Location: Mt. Pleasant,
OH
Posts: 1,249
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
One small caveat........When you clean up the threads, always use the tap, not a nylon bolt. Sometimes that thin CA doesn't all 'fire' and you'll have a permanently installed nylon bolt. Don't ask how I know this.
#3
Senior Member
Thread Starter
My Feedback: (9)
Join Date: Apr 2003
Location: Manvel,
TX
Posts: 1,337
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
Tis true, tis true. In fact even though I mentioned in my post about re tapping the hole, I should have also mentioned that you should spray a little kicker in the hole or even a tap can seize up if the ca has not all gone off.
Tom
Tom
#4
Senior Member
Join Date: Jan 2003
Location: Spring Hill,
FL
Posts: 4,734
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
Good tip!
I mentioned what you said in the article on my site about how to mount a wing. You really do need to wait for the CA to totally set up even if using a tap. I've had wood chips glued in my tap thread before and picking it out isn't any fun. I just let it set up over night and work on something else. Then I re-tap the threads.
Good tip!
I mentioned what you said in the article on my site about how to mount a wing. You really do need to wait for the CA to totally set up even if using a tap. I've had wood chips glued in my tap thread before and picking it out isn't any fun. I just let it set up over night and work on something else. Then I re-tap the threads.
Good tip!
#5
Senior Member
Join Date: May 2003
Location: east coast
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
For wing bolts, I perfer a brass insert w/ the proper thread glued into the wood.
Haven't had much luck w/ CA hardened threads...
Just my .02 worths...
Allen
Haven't had much luck w/ CA hardened threads...
Just my .02 worths...
Allen
#6
Member
My Feedback: (1)
Join Date: Aug 2003
Location: Shawnee,
KS
Posts: 70
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
I have a different way of doing Servo blocks.
I drill a hole to fit the yellow nyrod and then insert
the yellow nyrod in the hole. Then CA the yellow nyrod
in place and you have a screw holder that will hold.
Works for me.
HLC
I drill a hole to fit the yellow nyrod and then insert
the yellow nyrod in the hole. Then CA the yellow nyrod
in place and you have a screw holder that will hold.
Works for me.
HLC
#7
Senior Member
![Default](images/icons/icon1.gif)
CafeenMan
Had small experience with the tap...decided picking it out was too time consuming..dropped tap in acetone 20 mins. later it was clean. relubed it and will wait longer next time.
Had small experience with the tap...decided picking it out was too time consuming..dropped tap in acetone 20 mins. later it was clean. relubed it and will wait longer next time.
#8
![](/forum/images/badges/trading_plus_member.png)
My Feedback: (34)
![Default](images/icons/icon1.gif)
After adding some thin CA I like (after 5-10 min) to spray in some 'Kicker' and WAIT for another 5 minutes before 're-tapping'. I think when you squeeze the wood with either the tap or the bolt, some of the uncured CA is squeezed out of the wood and now you get to re-drill, re-tap and #^@$%%^*$%( one more time ![Smile](images/smilies/smile.gif)
Jerry
![Smile](images/smilies/smile.gif)
Jerry
#9
Junior Member
My Feedback: (2)
Join Date: Dec 2003
Location: Acworth, GA,
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
I find where it is necessary to harden the screw hole I use "All Threads" These are plastic pieces specifically sized to take all sizes of small screws. All you do is drill a hole, insert the All Thread and thin CA it in place. The screw goes into the plastic hole and requires torque to screw in and remove. Great for cowl screws.....they won't vibrate out. All Threads are available from Great Planes in sizes #2 to #10. More optins in size than using a piece of yellow Ni Rod. Best i have found so far
#10
Senior Member
Join Date: Aug 2003
Location: Port Orchard,
WA
Posts: 687
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
I have to admit, I prefer using blind nuts and #8 button head stainless hex screws with a wide flat washer. They are small, strong, and have a rounded head so they don't have such a protruding look to them. For really large planes, #10 screws. Besides the shiny stainless looks nicer.![Big Grin](images/smilies/biggrin.gif)
Patriot
![Big Grin](images/smilies/biggrin.gif)
Patriot
#12
Senior Member
Join Date: Jan 2003
Location: Spring Hill,
FL
Posts: 4,734
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
ORIGINAL: Jim Messer
I use those plastic dry-wall anchors. Buy a box of assorted sizes - drill a hole - pound in the correct size, secure with thin CA, then screw away. These hold tight - won't vibrate loose, and are relatively cheap.
I use those plastic dry-wall anchors. Buy a box of assorted sizes - drill a hole - pound in the correct size, secure with thin CA, then screw away. These hold tight - won't vibrate loose, and are relatively cheap.
#13
Senior Member
Join Date: Aug 2003
Location: Port Orchard,
WA
Posts: 687
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
I don't want to sound insulting but can't help it here.
I have to agree with cafeen-man. It may work, but for how long? I would rather use some old baling twine and bubble gum if that's the case.
Sorry, but I had to say it.
Patriot
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
Patriot
#14
Senior Member
Join Date: Nov 2003
Location: Freeport, TX
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
Staying with the original subject.... The CA works well as a thread hardener on hardwood and balsa too. I've been doing that since my first plane. Another use for CA in wood, is around the hinge points and control horn mounting area. I have never screwed a control horn onto a control surface since I've been in this hobby. I think it looks tacky and adds to the drag. Instead, I carve a indent into the control surface a bit deeper than the thickness of the base of the horn, cut a cover plate from 1/64 aircraft ply and CA it all together. I then take thin CA and "harden" the balsa for about 1/4" all around the horn. I have never had a failure, even after a crash the control horns were still intact. I'd post a pic but I'm not at home.
#18
![](/forum/images/badges/premium_member.png)
My Feedback: (2)
Join Date: Mar 2002
Location: Jamestown,
NY
Posts: 660
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
I can see using thin Ca to harden balsa and perhaps soft (pine, etc.) wood or ply thd's but why is it necessary in hardwood.? Used hardwood for years and never had a problem with the thd's pulling out? Usually, if you tighten nylon bolts down too much, the nylon breaks but the hardwood thd's, never! Another approach is to glue a steel "T" nut on the backside of the hole like you may do for motor mount bolts in a ply firewall and leave the hole smooth in the wing mounting block, then the nylon bolt engages the steel "T" nut th'd. only. Have used steel 1/4-20 "T" nuts and smaller th'd. sizes for years in ply blocks for wing mounts, motor mounts, cowls and landing gear blocks with great success!
Overkill can sometimes cause important airframe parts to break as a result of a crash and not easily replaced parts like mounting blocks, etc. A further thought is maybe your th'd taps are dull which cause poor quality thd's to be cut in hardwood blocks?? Just thoughts from an old frustrated machinist and engineer.![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
Overkill can sometimes cause important airframe parts to break as a result of a crash and not easily replaced parts like mounting blocks, etc. A further thought is maybe your th'd taps are dull which cause poor quality thd's to be cut in hardwood blocks?? Just thoughts from an old frustrated machinist and engineer.
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
#19
Senior Member
Join Date: Jan 2003
Location: Spring Hill,
FL
Posts: 4,734
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
flicka - I put CA in hardwood to oil-proof the threads more than anything else. I agree with you about hardwood. It's strong enough to hold a thread without help, but oil seems to be able to creep everywhere - under landing gear, into holes, etc.
#20
Senior Member
Join Date: Aug 2003
Location: Port Orchard,
WA
Posts: 687
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
cafeenman is right. i once say a little p-51 kit that really tore up the sky. Then, one day tore off the wing while doing and outside turn. ![Frown](images/smilies/frown.gif)
Crash investigation showed the bolt holes in the hardwood mount were stripped out cuz just a wheee bit of nitro got in there one way or another, and over time, oops.[:@]
Patriot
![Frown](images/smilies/frown.gif)
Crash investigation showed the bolt holes in the hardwood mount were stripped out cuz just a wheee bit of nitro got in there one way or another, and over time, oops.[:@]
Patriot
#21
Member
Join Date: Feb 2003
Location: Vancouver, BC, CANADA
Posts: 92
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
Skeletor. That sounds like a superb and clean looking way of mounting control horns. Would you be so kind as to post a photo essay on the subject?
Brad
Brad
#22
Senior Member
Join Date: Jun 2003
Location: Somewhere in,
TX
Posts: 642
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
Well the way I did it was to first make the holes the way I wanted them. Then put some thin CA in it to harden it up. Give it about an hour, then use a tap are clean the threads from any expanding CA effects. Worked for me.
#25
Senior Member
Join Date: Jan 2003
Location: Spring Hill,
FL
Posts: 4,734
Likes: 0
Received 0 Likes
on
0 Posts
![Default](images/icons/icon1.gif)
ORIGINAL: flicka5
Ca in hardwood th'ds for oil proofing is a good thought but something I have never done: maybe because my models don't last that long to be a problem?![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
Ca in hardwood th'ds for oil proofing is a good thought but something I have never done: maybe because my models don't last that long to be a problem?
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
![Big Grin](images/smilies/biggrin.gif)
what else.... Stuck My Stick 30 into the ground on a touch and go - rolled it too much and the turf caught a wing tip causing it to cartwheel 75 yards across the field. One broken turbulator spar, two dented wing tips and a totalled fuselage. If you look at this plane on the site, you'll see two different fins. Those are actually two completely different fuselages.
Oh yeah.... I lost Great Gonzo in the statosphere. Had her so high that all I could see was a little dot - no color, no shape. Took my eyes off her and haven't seen her since. I think she's still up there somewhere.
So, I started out last year with 5 planes and am down to 2 - one of which is retired.
An exerpt from the inlays article on my web site that goes along with your comment which I can certainly related to:
The next problem is deciding what glue to use. Water-based glue is dismissed because of warpage problems. Additionally, the inlay will be sandwiched between waxed paper which will slow down the drying process.
Epoxy is also a bad choice due to weight. Spray glue hardens and crumbles after a year or two. It's possible that eventually one of my planes will last that long, so spray glue is also a poor choice.
Epoxy is also a bad choice due to weight. Spray glue hardens and crumbles after a year or two. It's possible that eventually one of my planes will last that long, so spray glue is also a poor choice.