Drilling die cast aluminium - Garrard 301

[Wakefield Turntables]

Guys, need some advice. I would like to drill 3 small holes into the chassis of my Garrard 301. I intend mounting a tuned mass damper and stiffening the Garrard's chassis at the same time. I've been looking into drill bit. Would I be right in thinking that Cobalt drill bit's are the way forward, additional what's the best advice for drilling into the 301, is it best to take things slow and steady i.e. using the drill at a slow RPM?

Thanks

Andy

[walpurgis]

Not sure what the alloy is Andy, but make sure you've got a drill depth stop to suit unless you want to go right through.

[M6NTL]

Cobalt drills are fantastic, but as brittle as buggery - if you move about slightly while drilling you WILL snap the bit. High Speed Steel will be perfectly sufficient.
I always use drilling and tapping fluid (oil), but a bit of engine oil or even olive oil will do as a lubricant while drilling, and slow is best!


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[brian2957]

Yup , agreed , Aluminium isn't that hard so HSS drills should be sufficient . How thick , or depth of hole , is the piece you want to drill Andy , and what diameter is the hole to be drilled ?

[Wakefield Turntables]

Guys, thanks for the advice. I was wanting to make a tuned mass damper (TMD) for the underside of my Garrard 301. It looks like a don't need to drill straight into the chassis as the TMD just sits in place over the area it's supposed to dampen without the need of screws to fasten it down.

[Pharos]

I've been drilling die-cast boxes since the 60s, and always used HSS, and I'm about to do another project now using one.

If a job requires care and control, and is not a lot of hard work, as in drilling alloy, I use a hand drill because they have the advantage that control is more direct, both of pressure and speed, and you can feel any extra tight cutting and ease of a little.

The real difficulty I find with using a hand held electric drill is that speed regulation is often not very controllable or fine, and they love to really grab the material especially with a sharp drill.