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Drill Dilemma - Long Winded Story

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biglar

Joined: 14 Jan 2006
Posts: 457

Posted: Wed Apr 26, 2006 6:24 pm Post subject: Drill Dilemma - Long Winded Story

Long winded Lar in full cry.  Sorry for the length of this, but it makes =

a good story, even if at my expense.



I finally found the problem causing Vamoose' oil leak, and it's turning =

out to be a bear to fix.  In a nutshell, a machined piece is held onto =

the end of the crankshaft with four 8mm dowel pins, and four 3/8" =

hardened cap screws.  This one goes into the engine's rear oil seal.  A =

2nd piece with the splines for the output shaft bolts onto that with six =

1/4" AN bolts, and clamps the flex plate for the starter.=20



The 3/8" cap screws didn't hold torque, and were loose when I =

dis-assembled the parts.  One dowel pin had broken in half.  Apparently =

the six 1/4" bolts had bottomed out just as they were coming tight, and =

all had seemed well, but all 6 were broken off about 1/4" into the =

threads.  Safety wire on those was fine.  Getting the broken stubs out =

was....interesting.  They just grinned at an easy-out.  The oil seal had =

a tear in it.  The engine had only run for about 5 or 10 minutes before =

it started leaking the 1st time.  All subsequent runs were made without =

the prop, so's to see what was happening without getting my head knocked =

off.  Torque out of that engine must be awesome. =20



Original dowel pins are .314" (8mm) dia. x .620" long.  There are =

oversize pins available that are .343" x .756, and I want to use these =

for more shear strength but I've got to get the original pins out, and =

they're a press fit.  OK, 3 of them I drilled and tapped and used a =

home-made slide hammer and yanked them out.  No problem.....not too =

much....that a little creative language didn't take care of.  The 4th =

one - the broken one - is hardened somewhat.  Using the same pilot bit =

as on the others, it went about 1/4" into that broken pin before =

dulling.  I have no idea what kind of bit it was.  Kinda grey/shiny.  I =

then used every small bit I owned trying to drill deeper into that =

thing.  Not a chance.  Ruined every one of them.  Went to Lowe's today =

and bought 1/2 doz. assorted bits - cobalt, titanium, etc., etc.  Even a =

Hitachi one that claims to "last twice as long as others."  None of them =

even touched it.  Now, the big question - what can I use to drill that =

pin out of there ??  If I can't tap threads into it after drilling, (and =

I'll be very careful, believe me) I'll hafta go larger and drill it out =

completely.  What kind of bits will do this job ??  I know something =

can, cause that small pilot bit went in 1/4".       Help ! ! !



For re-assembly - I've already thoroughly cleaned the 3/8" threads, male =

and female, and will loctite them this time.  Suggestions for which =

version of loctite to use would be welcome.  I've drilled and tapped 6 =

more holes in the 2nd part, for a total of twelve 1/4" AN bolts.  They =

came in from A/C Spruce yesterday.  I drilled .2" (2/10ths) into the =

threads so's to put the shank of the bolts in shear rather than the =

threads as had been done.  Also drilled and tapped them deeper to =

eliminate any possibility of bottoming again.



I guess this has all been for the better, for all the frustration, =

because it would certainly have failed completely in a very short time =

in the air.  I never thought to even check it out, because the oil was =

clearly leaking from the input shaft of the re-drive on prior runs.  =

Only after installing the Speedi-Sleeve did that leak dry up and stop =

masking this 2nd one.  What a raging pain in the neck........but at =

least I've got a solution in sight now - if I can get that 4th dowel pin =

out of there.                              Lar.=20



Larry Bourne

Palm Springs, CA

Building Kolb Mk III

N78LB  Vamoose

www.gogittum.com

_________________
Larry Bourne
Palm Springs, CA
Building Kolb Mk IIIC
"Vamoose"

jadamson

Joined: 23 Mar 2006
Posts: 13

Posted: Wed Apr 26, 2006 7:41 pm Post subject: Re: Drill Dilemma - Long Winded Story

 	  Quote: 	
		  Now, the big question - what can I use to drill that =

pin out of there ?? If I can't tap threads into it after drilling, (and =

I'll be very careful, believe me) I'll hafta go larger and drill it out =

completely. What kind of bits will do this job ?? I know something =

can, cause that small pilot bit went in 1/4". Help ! ! ! 	




Hmm, trying to visualize & am thinking about some numbers here.  The dowel pin is 0.620" long but it's broken off in the machined piece.  So say half of the pin is left inside (~ 0.310" stuck).  And you've drilled into it 1/4", so you're not far from the end of the pin.



If I'm on track so far, seems like the best course - assuming you didn't break the bit off in the pilot hole - is simply to be patient & keep looking for better quality bits.  I'd try to find a good tool supply place .. Lowe's is my Sunday afternoon last resort.  Where I live, a local welding supply place has all kinds of quality tools.



If you did break the bit off in the pin, then a couple of other thoughts that come to mind are:

a) If the pin broke off fairly flush with - or above - the surface it's stuck in, would it be possible to weld a head onto it?  Have seen that done on occasion.  8mm's pretty small but might still be do-able.

b) Have you tried applying mild heat and/or cold to the parts?  Obviously want to be careful here so as not to introduce new problems.



Good luck!

WhiskeyVictor36(at)aol.co
Guest

Posted: Wed Apr 26, 2006 7:42 pm Post subject: Drill Dilemma - Long Winded Story

In a message dated 4/26/2006 10:25:39 P.M. Eastern Standard Time,  

biglar(at)gogittum.com writes:



Now, the  big question - what can I use to drill that =

pin out of there  ?? 

Larry,

 

I read about a method, somewhere a long time ago, that will permit one to  

drill through hard material, even spring steel.  The trick is to use a  VERY 

slow drill speed, along with VERY high pressure.  Using a drill press  would be 

the best way, but if that is not possible, perhaps you could enlist the  help 

of some beefy friends to assist you in using a handheld drill  motor.

 

Good luck,  



Bill  Varnes

Original Kolb FireStar

Audubon  NJ

DAquaNut(at)aol.com
Guest

Posted: Wed Apr 26, 2006 7:43 pm Post subject: Drill Dilemma - Long Winded Story

In a message dated 4/26/2006 9:25:39 P.M. Central Standard Time,  

biglar(at)gogittum.com writes:



Only  after installing the Speedi-Sleeve did that leak dry up and stop =

masking  this 2nd one.  What a raging pain in the neck........but at =

least  I've got a solution in sight now - if I can get that 4th dowel pin =

out of  there.                     Lar.=20



Larry  Bourne

      Lar,

 Seems I remember In my dune buggy building days we drilled the crank  for a 

total of 8 dowel pins. Maybe that would help your situation??? Hope you  get 

it solved.

 

          Ed      Do Not Archive

biglar

Joined: 14 Jan 2006
Posts: 457

Posted: Wed Apr 26, 2006 8:05 pm Post subject: Re: Drill Dilemma - Long Winded Story

Nope, the broken piece is in the crankshaft, and, thankfully, I was careful and didn't break off a drill bit.  I tried heating the 1st one I pulled, but didn't notice any difference, and don't really like to heat that component.  I'm not crazy about Lowe's myself, but figured brands like Bosch, DeWalt, etc., would be the same in any store.  I like the welding shop idea, I'll try it tomorrow.  Thanks.                   

Lar.

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_________________
Larry Bourne
Palm Springs, CA
Building Kolb Mk IIIC
"Vamoose"

DAquaNut(at)aol.com
Guest

Posted: Wed Apr 26, 2006 8:33 pm Post subject: Drill Dilemma - Long Winded Story

In a message dated 4/26/2006 11:06:51 P.M. Central Standard Time,  

biglar(at)gogittum.com writes:



I like  the welding shop idea, I'll try it tomorrow.  Thanks.        

Lar.





Lar,

 If you can find a someone with a tig machine he will be more likely  to have 

success in tacking only where it needs to go, verses mig or stick  

welding.With tig the welder has more precise control than mig or stick.

 

          Ed                       Do Not Archieve

NeilsenRM(at)comcast.net
Guest

Posted: Wed Apr 26, 2006 8:41 pm Post subject: Drill Dilemma - Long Winded Story

Lar



I had a similar problem drilling thru the bellcrank on my tail wheel. Just 

couldn't get the bit to even scratch the surface. I went to a tool store 

called Production Tool and bought a drill bit for hardened steel. It just 

about pulled its self thru the steel. The guy that sold it to me said to be 

careful with the bit because it was very brittle. Seems like he said it 

would shatter if dropped on a hard surface. It was a bit pricey but well 

worth the aggravation it saved.



Hope this helps.



Rick Neilsen

Redrive VW powered MKIIIc



---

slyck(at)frontiernet.net
Guest

Posted: Wed Apr 26, 2006 8:58 pm Post subject: Drill Dilemma - Long Winded Story

The slow turning drill at high pressure is good advice, as is the

special bit.  In addition a little bit of "tap magic" will help the

bit take a bite.

-BB

On 26, Apr 2006, at 10:22 PM, Larry Bourne wrote:



 	  Quote: 	
		   



 Long winded Lar in full cry.  Sorry for the length of this, but it 

 makes =

 a good story, even if at my expense.



 I finally found the problem causing Vamoose' oil leak, and it's 

 turning =

 out to be a bear to fix.  In a nutshell, a machined piece is held onto 

 =

 the end of the crankshaft with four 8mm dowel pins, and four 3/8" =

 hardened cap screws.  This one goes into the engine's rear oil seal.  

 A =

 2nd piece with the splines for the output shaft bolts onto that with 

 six =

 1/4" AN bolts, and clamps the flex plate for the starter.=20



 The 3/8" cap screws didn't hold torque, and were loose when I =

 dis-assembled the parts.  One dowel pin had broken in half.  

 Apparently =

 the six 1/4" bolts had bottomed out just as they were coming tight, 

 and =

 all had seemed well, but all 6 were broken off about 1/4" into the =

 threads.  Safety wire on those was fine.  Getting the broken stubs out 

 =

 was....interesting.  They just grinned at an easy-out.  The oil seal 

 had =

 a tear in it.  The engine had only run for about 5 or 10 minutes 

 before =

 it started leaking the 1st time.  All subsequent runs were made 

 without =

 the prop, so's to see what was happening without getting my head 

 knocked =

 off.  Torque out of that engine must be awesome. =20



 Original dowel pins are .314" (8mm) dia. x .620" long.  There are =

 oversize pins available that are .343" x .756, and I want to use these 

 =

 for more shear strength but I've got to get the original pins out, and 

 =

 they're a press fit.  OK, 3 of them I drilled and tapped and used a =

 home-made slide hammer and yanked them out.  No problem.....not too =

 much....that a little creative language didn't take care of.  The 4th =

 one - the broken one - is hardened somewhat.  Using the same pilot bit 

 =

 as on the others, it went about 1/4" into that broken pin before =

 dulling.  I have no idea what kind of bit it was.  Kinda grey/shiny.  

 I =

 then used every small bit I owned trying to drill deeper into that =

 thing.  Not a chance.  Ruined every one of them.  Went to Lowe's today 

 =

 and bought 1/2 doz. assorted bits - cobalt, titanium, etc., etc.  Even 

 a =

 Hitachi one that claims to "last twice as long as others."  None of 

 them =

 even touched it.  Now, the big question - what can I use to drill that 

 =

 pin out of there ??  If I can't tap threads into it after drilling, 

 (and =

 I'll be very careful, believe me) I'll hafta go larger and drill it 

 out =

 completely.  What kind of bits will do this job ??  I know something =

 can, cause that small pilot bit went in 1/4".       Help ! ! !



 For re-assembly - I've already thoroughly cleaned the 3/8" threads, 

 male =

 and female, and will loctite them this time.  Suggestions for which =

 version of loctite to use would be welcome.  I've drilled and tapped 6 

 =

 more holes in the 2nd part, for a total of twelve 1/4" AN bolts.  They 

 =

 came in from A/C Spruce yesterday.  I drilled .2" (2/10ths) into the =

 threads so's to put the shank of the bolts in shear rather than the =

 threads as had been done.  Also drilled and tapped them deeper to =

 eliminate any possibility of bottoming again.



 I guess this has all been for the better, for all the frustration, =

 because it would certainly have failed completely in a very short time 

 =

 in the air.  I never thought to even check it out, because the oil was 

 =

 clearly leaking from the input shaft of the re-drive on prior runs.  =

 Only after installing the Speedi-Sleeve did that leak dry up and stop =

 masking this 2nd one.  What a raging pain in the neck........but at =

 least I've got a solution in sight now - if I can get that 4th dowel 

 pin =

 out of there.                              Lar.=20



 Larry Bourne

 Palm Springs, CA

 Building Kolb Mk III

 N78LB  Vamoose

 www.gogittum.com

terry(at)juliaswartz.com
Guest

Posted: Thu Apr 27, 2006 3:22 am Post subject: Drill Dilemma - Long Winded Story

Larry



If you can't use heat maybe you could try cold. Get some liquid nitrogen, it

boils at -325F degrees. Sounds dangerous but really isn't. I used to

distribute bull semen for artificial insemination of cows and we used liquid

nitrogen by the gallons. We bought it at the local welding supply where they

sell oxygen and acetylene and transported it vacuum insulated storage tanks.

For very small quantities you could use a thermos, vacuum insulated type,

preferably stainless steel, but the glass type will work for transporting.

You will have to use it right away as it will boil away in about 24 hours.

Chilling the pin may be the challenge. I removed all warts from family and

friends by dipping a drift punch in the nitrogen until it was chilled, then

holding the punch on a wart for just a few seconds until frozen. The warts

then fell of in a couple days. This process may work for you. I've used it

for other press fit applications and it worked very well. Liquid nitrogen

can be dipped with a plastic pitcher and poured but it will be boiling

continuously in the pitcher. Of course avoid contact with skin or you will

have instant frost bite. I don't recall the price, maybe $1.00 per gallon.

Another source would be your local artificial inseminator, check yellow

pages. Your local welding supply may not be interested in filling a thermos.



Good luck



Terry



--

biglar

Joined: 14 Jan 2006
Posts: 457

Posted: Thu Apr 27, 2006 4:54 am Post subject: Drill Dilemma - Long Winded Story

I didn't, and can't use my drill press.  The engine is on the plane.  That 

drill bit yesterday walked right into it........for a while, so I know it's 

possible................??   I'm familiar with, and did try, the slow speed, 

high pressure idea.       Thanks.             Lar.                Do not 

Archive.



Larry Bourne

Palm Springs, CA

Building Kolb Mk III

N78LB  Vamoose

www.gogittum.com



---

_________________
Larry Bourne
Palm Springs, CA
Building Kolb Mk IIIC
"Vamoose"

biglar

Joined: 14 Jan 2006
Posts: 457

Posted: Thu Apr 27, 2006 4:54 am Post subject: Drill Dilemma - Long Winded Story

Yah, this crank was drilled for 8, but 4 were drilled and tapped for 3/8 

fine thread for the cap screws.                       Lar.



Larry Bourne

Palm Springs, CA

Building Kolb Mk III

N78LB  Vamoose

www.gogittum.com



---

_________________
Larry Bourne
Palm Springs, CA
Building Kolb Mk IIIC
"Vamoose"

jr(at)rometool.com
Guest

Posted: Thu Apr 27, 2006 5:36 am Post subject: Drill Dilemma - Long Winded Story

Being an ole Tool maker, many times I have used this method to remove 

hardened broken dowel pins and even bolts.....use a short piece of steel 

tubing, alittle less in diameter than the dowel or screw, position the 

end of the tubing on the broken dowel and using a stick welder and a 

small welding rod, reach through the tubing with the welding rod and 

puddle weld the tube to the dowel and walah, most of the time anyway.



Larry Bourne wrote:

[quote] 



 Yah, this crank was drilled for 8, but 4 were drilled and tapped for 3/8 

 fine thread for the cap screws.                       Lar.



 Larry Bourne

 Palm Springs, CA

 Building Kolb Mk III

 N78LB  Vamoose

 www.gogittum.com



 ---

jadamson

Joined: 23 Mar 2006
Posts: 13

Posted: Thu Apr 27, 2006 11:38 am Post subject: Re: Drill Dilemma - Long Winded Story

 	  jr(at)rometool.com wrote: 	
		   .....use a short piece of steel 

tubing, alittle less in diameter than the dowel or screw, position the 

end of the tubing on the broken dowel and using a stick welder and a 

small welding rod, reach through the tubing with the welding rod and 

puddle weld the tube to the dowel and ...



 --- 	




Now that's clever!  Really adds a nice refinement to the welding idea, especially when the break is down in the threads.



John A

eagle1(at)commspeed.net
Guest

Posted: Fri Apr 28, 2006 11:48 am Post subject: Drill Dilemma - Long Winded Story

Lar, Your local dermatologist has those little nitrogen bottles that they 

burn off warts etc. You might go to one and buy an extra.

   Az Bald Eagle



---

slyck(at)frontiernet.net
Guest

Posted: Fri Apr 28, 2006 1:31 pm Post subject: Drill Dilemma - Long Winded Story

Yeah!  Lar's a real warty old guy..........



On 28, Apr 2006, at 3:45 PM, George E. Thompson wrote:



[quote] 

 <eagle1(at)commspeed.net>



 Lar, Your local dermatologist has those little nitrogen bottles that 

 they

 burn off warts etc. You might go to one and buy an extra.

    Az Bald Eagle



 ---

biglar

Joined: 14 Jan 2006
Posts: 457

Posted: Fri Apr 28, 2006 2:58 pm Post subject: Drill Dilemma - Long Winded Story

But cool, for alla that.                       Do not Archive.



Larry Bourne

Palm Springs, CA

Building Kolb Mk III

N78LB  Vamoose

www.gogittum.com



---

_________________
Larry Bourne
Palm Springs, CA
Building Kolb Mk IIIC
"Vamoose"

jindoguy(at)gmail.com
Guest

Posted: Fri Apr 28, 2006 7:35 pm Post subject: Drill Dilemma - Long Winded Story

In my haste to extoll the virtues of masonry bits, I forgot one other

option. Call some local machine shops and ask them who burns out taps in th=

e

area. Some shop always has an electric discharge tap burner. Worth a try.



On 4/28/06, George E. Thompson <eagle1(at)commspeed.net> wrote:

[quote]

 

 eagle1(at)commspeed.net>



 Lar, Your local dermatologist has those little nitrogen bottles that they

 burn off warts etc. You might go to one and buy an extra.

    Az Bald Eagle



 ---

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