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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

drilling cast iron keel for adding bolts

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Garboard
Deckhand

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USA
13 Posts

Initially Posted - 04/09/2018 : 15:37:13

I have a 1980 C-25 with keel bolt worries (I posted a few days ago regarding this and my plans/concerns)...
Now I have begun drilling into the top of the keel from inside the boat. (after considering how to add more support to the fixed cast iron keel and hearing from the helpful folks on this forum, I have decided to bore and tap holes in the keel...this is the method suggested by Catalina Direct who offer a kit.
However being a penny pincher (and an experienced tradesman) I've decided to come up with my own "kit"...
So I have begun boring several 1/2" holes into the keel...the first approx 4" down from the bilge are an easy chore consisting of fiberglass and wood (teak?)...
However beginning to bore into the cast iron is proving "impossible"! I have started with new bits, black oxide and cobalt...and have experimented with smaller diameter pilot holes...but in each case I am making no measurable progress...
I talked with a relative who is a machinist, looked online too and common wisdom seems to be: --that cast iron should drill fairly easily...
-that black oxide bits should work fine...
-that lubricate (cutting oil) is/isn't a good idea...(yes, I've tried both ways)...
SO CAN ANYBODY SHARE THEIR INSIGHTS ON THIS SUBJECT, PLEASE!

JLR

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 04/09/2018 : 16:18:33

Try the Search feature looking for the words "keel bolt drill oil" in the C-25 forum, including the archives.

One suggestion I've heard is to drill pilot holes--another is to use cutting oil. I have no personal experience.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

SKS
Navigator

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USA
161 Posts

Response Posted - 04/09/2018 : 17:26:27

I've read about drilling into the cast iron keels.
From what I've gleaned, Catalina wasn't very particular about the grade of cast iron they used, since the keels are there for ballast, not structural support.
The issue is, the keels may have a lot of slag in them. Not iron, but more like rock. Maybe a hammer drill is needed ?
I wish I had more to offer.

"Lady E" 1986 Catalina 25: Fin Keel, Standard Rig, Inboard M12 Diesel, Sail No. 5339
Sailing out of Norwalk Cove Marina, Connecticut

dasreboot
Admiral

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803 Posts

Response Posted - 04/10/2018 : 04:05:57

i did it and treaded it for zincs. it's not really hard. pilot hole and cutting oil. I just sprayed the bit and hole occasionally with spray lubricant, may have been pb blaster. not the best , but it worked. have an extra bit with you unless you are close enough to a store to get one. btw to tell you how soft it is, I did it with a ryobi cordless drill. EDIT:oops reading more i see that you have fixed keel. This was a swing keel. perhaps cast by a different company.

Todd Lewis
Eowyn 87 TR/WK C25 #5656
ARWEN 84 TR/SK C25 #4031
www.mainsailsailingschool.com

Edited by - dasreboot on 04/10/2018 04:08:13

odonnellryanc
Navigator

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108 Posts

Response Posted - 04/10/2018 : 07:37:46

I've had to drill through not a keel, but thick steel a few times.

From what I understand heat is really bad for this. The oil helps dissipate the heat slightly, but I believe it is more important to not operate an an extreme RPM. Go very slow. If you can't control the speed well with your drill look into a drill that makes that easier.

And of course the right bits...

But yeah, just from googling around about this issue it seems that a lot of people have problems here due to slag, as mentioned. That sounds rough.... and probably takes some creativity...

islander
Master Marine Consultant

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USA
3992 Posts

Response Posted - 04/10/2018 : 09:28:56

As mentioned, Slow RPM with oil removing the drill to clear the hole of the shavings frequently. Your not drilling through a 1'4" plate so it will take time and patience. You also do not want to break a bit off down in the hole. That would be a real PIA.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Dave5041
Former Mainsheet Editor

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USA
3754 Posts

Response Posted - 04/10/2018 : 10:06:30

I agree with the above. Plenty of oil to wash out the debris and keep the bit cool. Pull the bit out frequently and wipe it down because the debris is more like sludge than spirals. I had no problem drilling and tapping my swing keel for zincs. Pilot holes are essential and do it in stages, maybe 1/8, 1/4, 3/8, and 1/2.

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

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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.