Drilling through lead keel
John Redmond
I'm seeking information on how to drill through a lead keel for keel bolts.
In particular, I must drill down through approximately nineteen inches of
wood before reaching my seven inch thick lead keel. The bolt holes must be
3/4 of an inch, and I'm not sure what type of drill bit or bits I should
use. I've been told that high speed drill bits with modified cutting angles
can be used. Information on drilling speeds, lubrication, and clearing the
chips would be helpful as well.
Gerrie Warner
had a very big industrial drill with adjustable speeds and high tourqe
value. You can use just regular high speed bits but keep the speed very
low. Are you using some sort of jig to facilitate a staight run? There
is a lot of resistance involved so go slow and be carefull.
--
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742 92 Östhammar, Sweden
Tel. Country code then: 17310899
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Bryon Kass
John Redmond wrote:
>
> I'm seeking information on how to drill through a lead keel for keel bolts.
> In particular, I must drill down through approximately nineteen inches of
> wood before reaching my seven inch thick lead keel. The bolt holes must be
> 3/4 of an inch, and I'm not sure what type of drill bit or bits I should
> use. I've been told that high speed drill bits with modified cutting angles
> can be used. Information on drilling speeds, lubrication, and clearing the
> chips would be helpful as well.
are you going to keep the bolts in the lead. You cannot tap the
lead as it is much too soft. You should cross drill a large hole
in the keel to meet your down drilled holes and stuff a nut there
to thread on your bolts. I also suggest using stainless.
Bryon Kass
webmaster and
Custom Design
150 Mechanic St.
Foxboro, MA 02035
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in THE ENGINE ROOM http://www.ici.net/customers/cusdn
macnaughton.com
I hate to flatly contradict anyone but I would not use stainless bolts
through a wood keel into lead. Stainless is often very susceptible to
crevice corrosion, especially where it goes through two pieces of wood or
between wood and something bolted to it. I have personally seen quite a
number of bolts in sizes up to 1/2" diameter eaten completely through in a
nice neat line just like they'd been cut with a hack saw. In my opinion the
best choice is silicon bronze bolts, preferably the Everdur formulation.
These are very long lived.
Sincerely,
Tom MacNaughton
http://www.macnaughtongroup.com
Jon Etheredge
Bryon Kass wrote:
>
> Normal high speed steel bits should work OK. The question is how
> are you going to keep the bolts in the lead. You cannot tap the
> lead as it is much too soft. You should cross drill a large hole
> in the keel to meet your down drilled holes and stuff a nut there
> to thread on your bolts. I also suggest using stainless.
Keel bolts can be threaded into a lead keel. To cite one example, L. F.
Herreshoff specs keel bolts of Tobin Bronze 1/2" with 13 tpi to be
threaded into the lead keel to a depth of 6-8 times their diameter on
the Rozinante design. He specified similar keel fastenings on many of
his designs. It may be that L. Francis was atypical in this regard but I
believe I have seen this in the work of other designers as well.
One other point, stainless steel keel bolts are not always a good idea.
They are probably a down right bad idea on a wood boat with bronze and
copper fastenings. Tobin bronze or Everdur bronze may be a better choice
in this case. The point here is that the choice of keel fastening
material should take several factors in to account and these factors
vary from boat to boat. There is no one "right" choice for all
situations.
Jon Etheredge
Paul and Cindy Kruse
"John Redmond" <reed...@email.msn.com> wrote:
< I'm seeking information on how to drill through a lead keel for keel bolts.
< In particular, I must drill down through approximately nineteen inches of
< wood before reaching my seven inch thick lead keel. The bolt holes must be
< 3/4 of an inch, and I'm not sure what type of drill bit or bits I should
< use. I've been told that high speed drill bits with modified cutting angles
< can be used. Information on drilling speeds, lubrication, and clearing the
< chips would be helpful as well.
I have never done this sort of job, but I have drill many hundreds of holes into
lead over the years. Sharpen your drill bit with the same angle recommended for
wood. This is a much greater angle than you would normally use for steel.
Machinery Handbook is a good reference. For holes the size you are talking
about, I personally would even increase the angle from what is recommended in
the book. (If you do not know how to sharpen a drill bit, I would pay a
machinist to do it for you. If you to not grind both sides exactly the same, it
may drift.)
Then follow the other advice that you have already gotten. Go slow and make a
jig so you can also go straight. Back out often to clear the chips. I do not
normally use any lubricant at all for lead.
Paul Kruse
While I do monitor this newsgroup, my server is
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Have a great day,
plk...@iu.net (Paul Kruse)