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Re: [Amps] Workshop Danger

To: conrad@g0ruz.com, amps@contesting.com
Subject: Re: [Amps] Workshop Danger
From: TexasRF@aol.com
Date: Fri, 13 Sep 2013 11:08:30 -0400 (EDT)
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Oh for the good old days when we would drill a series if 1/4" holes around  
a circle, knock the center out with a hammer and use a half round file to 
clean  it up.
 
I still use that technique to make square holes for a blower  inlet.
 
73,
Gerald K5GW
 
 
 
In a message dated 9/13/2013 6:24:59 A.M. Pacific Daylight Time,  
conrad@g0ruz.com writes:

For tube  sized holes the Q max metal punches have always worked very 
well for me  even on 2mm aluminium. I think that biggest one I have is 
75mm. I've gone  solid state now so it's less of a problem. I have 
collected the full set  over the years and they are still going strong.

I a hole is bigger than  75mm I usually get someone with appropriate 
tools to do it for me these  days.

__________________________________________________

73

Conrad  G0RUZ IO93FR


North Wakefield Radio  Club

__________________________________________________
On  13/09/2013 12:55, peter chadwick wrote:
> Jim,
>
> I have  got from somewhere a 'circle cutter'. The difficulty with the 
plain fly cutter  is that it is inherently unbalanced and so has a tendency to 
dig into the work  and 'pick it up'. My circle cutter is effectively two fly 
cutters on opposite  sides of the central shaft: as they can be moved 
individually, they need very  careful setting up. Better to use than a drill 
press is a vertical milling  machine, because
>
> a)you can get a much finer feed to avoid  digging in and
>
> b)you are less likely to have the drill chuck  decide to part company 
with the arbor or even the arbor itself get wrenched  out and Morse taper 
damaged if it does dig in.
>
>
> If you  have a variable speed drive, that helps a lot too.
>
> Another  difficulty you can get is the drill chuck coming off the arbor. 
With a Jacobs  chuck, a good way to avoid that is  (using a lathe) drill 
through the  base of the chuck in the centre. Tap the hole 6-32. Then drill a 
corresponding  hole in the arbor and tap the arbor 4-40. A 4-40 screw and 
washer attaching  the chuck to the arbor and they won't come apart, but if you 
want them to,  removing the 4-40 screw enables you to use a 6-32 screw to 
jack them apart.  The arbors for my mill also have a drawscrew hole tapped 
10mm, so a long bolt  stops the Morse taper arbor shifting.
>
>
> A kit of  suitable clamping dogs and spacers is a good investment: even 
then, I've  things move and as a result, break a half inch diameter end  mill!
>
> But yes, fly cutters can be dangerous. So can all  workshop machines - 
other really nasty ones include a revolving wire brush (it  can spit wire 
bristles at you) and a grindstone, especially if some fatherless  wotsit has 
ground aluminium on it clogging the pores!
>
>
>  Of course, there's always the nearest smaller size hole saw and a half 
round  file....
>
>
> 73
>
> Peter G3RZP
>  _______________________________________________
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> Amps@contesting.com
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