[Shop-talk] hole sawed 1/4" thick steel post undersized

[john niolon]

clamp a piece of thinner plate (say 1/8") that is larger than the hole 
enough to get two good clamps on it. I'd cross mark it to get the center 
then do the same to the hole in the post.  line up the cross marks... drill 
the pilot hole in the center of the clamped plate which is also the center 
of the existing hole.  when you drill thru the clamped plate it will act as 
your pilot hole for the thicker post material

It might be quicker and easier to just predrill the clamped plate  then just 
center it on the smaller post hole... same difference but you can predrill 
with a press and save your back leaning on the hand drill.  Keep it oiled

john


Chinese Proverb
When someone shares something of value with you and you benefit from
it,  you have a moral obligation to share it with others. Pay it forward

----- Original Message ----- 
From: "old dirtbeard" <dirtbeard at pacbell.net>
To: <shop-talk at autox.team.net>
Sent: Sunday, July 08, 2007 5:36 PM
Subject: [Shop-talk] hole sawed 1/4" thick steel post undersized


> Hey guys,
>
> Well the subject line sort of tells it all. I was following instructions 
> for
> installing a fire department emergency open switch for our electric 
> driveway
> gate (I got cited and was given until next week to install it). The
> instructions said drill/bore 3/4" hole for mounting the switch, which I 
> did in
> a 6" by 6", 1/4" thick steel square gate post.
>
> Well it is big enough for the switch, but not the nut that holds it in 
> (they
> were assuming access to the back of he plate, but this is a blind 
> location). I
> have a face plate that will hold it to the post.
>
> Anyway, I have a 3/4" hole where it really needs to be about 1" (it is has 
> a
> very thick 7/8" across the flats nut).
>
> I need a different way to attach the 3/4" cylinder switch to the stainless
> steel face plate or a way to open up the hole about 1/4".
>
> I could look for a very thin nut, but that will take some time. I probably
> could epoxy the switch to the plate and forgo the nut (this may be my
> best/easiest solution). I don't think I can hole saw it again as I would 
> not
> have a pilot. I can try grinding it out, but that will take some time with
> that thick steel. I can get a blade for the Roto Zip, or the jig saw or 
> the
> Sawzall. I could take the air hammer to it. Of course I can go out there 
> with
> the torch and cut it open, but then I would have to repaint the post, and
> probably the gate and the other post so it would match.
>
> I am just thinking somebody here has a clever solution for increasing the
> diameter of an undersized hole in a thick piece of steel in a very visible
> location. Thanks in advance...
>
> best,
>
> doug
>
> '72 BSA B50SS
> '74 Triumph TR6
> '01 Harley XLH883
> '03 GMC Cargo Van
> _______________________________________________
> jniolon at bham.rr.com
>
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