Catalina - Capri - 25s International Assocaition Logo(2006)  
Assn Members Area · Join
h.jpg Home.
a.jpg Association Forum
s.jpg Ships Store
c.jpg Cruising
r.jpg Racing
t.jpg Technical Tips
g.jpg Photo Gallery - New
o.jpg Boat Search - Updated
m.jpg Manuals & Brochures
3rdrpt.jpg Swap Meet
l.jpg Links
f.jpg Officer Flag Line & Staff
b.jpg Bylaws & Constitution
 
1.jpg Members Area
1.jpg Join the Association
 
Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
 
Association Forum
Association Forum
Home | Profile | Register | Active Topics | Forum Users | Search | FAQ
Username:
 Password:
Save Password
Forgot your Password?

 All Forums
 Catalina/Capri 25/250 Sailor's Forums
 General Sailing Forum
 Drilling out stainless screws		  New Topic  Topic Locked
 Printer Friendly
Author Previous Topic Topic Next Topic  

OJ
Master Marine Consultant

Member Avatar

USA
4382 Posts
Initially Posted - 07/06/2014 :  18:25:13  Show Profile
In my exit block thread I reference the need to drill the heads off the ss screws that had seized in the mast.

I have filed what is left of the studs flush with the mast. Used a "prick punch" as a starter for the drill bit. Appears the bit has drifted as the hole is no longer dead center in the stud. I am not making much headway - very little metal bits falling out.

I plan (hope) to re-tap these holes so I need to be pretty precise with the pilot holes.

Any suggestions for keeping the bit centered? Should I source high speed steel bits to make better progress?

I purchased various Dremel bits and quickly discovered how completely under powered it is for this application.
Edited by - OJ on 07/06/2014 18:28:31

pastmember
Master Marine Consultant

Members Avatar

2402 Posts
Response Posted - 07/06/2014 :  19:32:47  Show Profile
Should you ignore the old screws now that the heads are flush, drill new holes in the exit blocks and tap fresh mast meat? The screws are not under serious loads and don't have to be in the corners of the hardware.
Edited by - pastmember on 07/06/2014 19:35:56
Go to Top of Page

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts
Response Posted - 07/07/2014 :  17:25:12  Show Profile
Thanks Frank! I would have probably never thought of that! Too logical for my brain! I made that plan "B".

Posted the same question on SailNet and received another solution that worked perfect:

"Use a true Colbalt drill bit and cutting oil (not 3-in-1 oil). If the drill wanders change the angle (naturally) until you're centered again."

Fortunately after drilling out the center of the stud, the remainder twisted out. No need to re-tap, just chase the threads to clean them out:
Edited by - OJ on 07/07/2014 17:44:27
Go to Top of Page

jduck00
Captain

Members Avatar

USA
313 Posts
Response Posted - 07/07/2014 :  18:19:26  Show Profile
Left handed drill bits. I've used them with good success.
Edited by - on
Go to Top of Page

pastmember
Master Marine Consultant

Members Avatar

2402 Posts
Response Posted - 07/07/2014 :  20:03:41  Show Profile
Well done!
Edited by - on
Go to Top of Page

PZell
Admiral

Members Avatar

USA
548 Posts
Response Posted - 07/08/2014 :  10:48:09  Show Profile
Remove the head on seized fastener. Then use nail punch to poke the threads through. Leaves the hole pretty much the same so you can go ahead and retap.
Edited by - on
Go to Top of Page

OLarryR
Master Marine Consultant

Members Avatar

USA
3466 Posts
Response Posted - 07/10/2014 :  03:37:30  Show Profile  Visit OLarryR's Homepage
I know that you are past this point already, however, I had a similar issue when I replaced my exit blocks, last year. The screws appeared to be frozen/seized and I would also have to drill them out. I wound up delaying replacing the blocks since the old ones still worked and so I just put the new ones aside for awhile.

Soon afterwards, I was replacing my standing rigging - Hired Atlantic Riggers out of Annapolis to come down and replace my standing rigging. The guy did so and with the mast remaining upright ! Anyway, since he was on my boat, I discussed with him the trouble I was having removing the exit block screws and he offered to give it a try since he had an impact power drill with a screwdriver bit. The impact power drill did the trick ! The screws came out and were able to be reused installing the new exit blocks. He did not charge for this assistance.
Edited by - OLarryR on 07/10/2014 03:39:00
Go to Top of Page

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts
Response Posted - 07/10/2014 :  09:04:39  Show Profile
quote:
Originally posted by OLarryR

. . . he had an impact power drill with a screwdriver bit. The impact power drill did the trick ! The screws came out and were able to be reused . . .


Good of you to share Larry. Yeah, sometimes it definitely pays to stop and ponder.

After I drilled the heads, I took a break and read a thread on Sailnet on this very topic. Briefly, MaineSail shared that an impact drill with ~1,200 BPM has a high percentage of success.

As others here have shared, Tef Gel is an excellent product for preventing galvanic corrosion.

As I have other machine thread screws in the mast and boom, this was the perfect justification for the new 20v impact drill I just acquired!

Edited by - OJ on 07/10/2014 09:07:35
Go to Top of Page

Akenumber
Navigator

Members Avatar

USA
247 Posts
Response Posted - 07/16/2014 :  20:56:39  Show Profile
I agree with jduck00. Quality left hand drill bit has always worked better than any other extractor for me.
Edited by - on
Go to Top of Page

Arlyn Stewart
Master Marine Consultant

Members Avatar

USA
2980 Posts
Response Posted - 07/18/2014 :  04:47:09  Show Profile  Visit Arlyn Stewart's Homepage
I'm left wondering what it is about a left hand drill bit that allows success? Could it be the sharpness of the bit? Stainless will work harden very quickly with a dull or improperly sharpened bit and once that happens the drilling process is all but shut down.

By using a left hand bit, the bit is probably sharp (not having been dulled by general use).

Cutting oil is critical as it carries heat away, which prevents or limits the work hardening.
Edited by - Arlyn Stewart on 07/18/2014 04:50:01
Go to Top of Page

TakeFive
Master Marine Consultant

Members Avatar

2272 Posts
Response Posted - 07/18/2014 :  05:52:29  Show Profile
quote:
Originally posted by Arlyn Stewart

I'm left wondering what it is about a left hand drill bit that allows success? Could it be the sharpness of the bit? Stainless will work harden very quickly with a dull or improperly sharpened bit and once that happens the drilling process is all but shut down.

By using a left hand bit, the bit is probably sharp (not having been dulled by general use).

Cutting oil is critical as it carries heat away, which prevents or limits the work hardening.

I think the left hand bit prevents the drilling from driving the threads further into the hole. Once you've drilled out the core and the threads are more flexible, the reverse rotation helps to extract the threads from the original tap.
Edited by - on
Go to Top of Page

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts
Response Posted - 07/18/2014 :  07:46:09  Show Profile
And it is a fair screw extractor if it binds.
Edited by - on
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Topic Locked
 Printer Friendly
Jump To:
Association Forum © since 1999 Catalina Capri 25s International Association Go To Top Of Page
Powered By: Snitz Forums 2000 Version 3.4.06
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.