[Amps] Workshop Danger

[Conrad Farlow]

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
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps