The Home Machinist!

Um, lot to digest there I'll get back to you a little later with a fuller reply. In meantime I'll order some more 3mm sheet to practise drililing on and some drill bits including centering bits.
Big thanks to you

Once again, thank you very much, for a very detailed, informed reply. Oh, you didn't mention, Helex angle, would this be a consideration? Centering drill bits. " Centre drill bits are often referred to as Slocomb drill bits which is used as counter sink holes or starter holes for bigger drill b...

OK, how does one determine the direction of the grain? Should be quite obvious by simply looking at the surface of the material. It tends to be directional (generally parallels the long side, or the rolling direction), but may be difficult to see if the surface has received any kind of treatment af...

Um, ok, some interesting stuff on the link.
Cheers.

OK, how does one determine the direction of the grain?

Harold_ V. Very knowledgable and complete reply. Thank you. I will try the twist drill approach as mentioned in your earlier post. I've been reading up on center drill bits and spotting hole drill bits. I will read up and research twist drill bits, a bit.... sorry :) I bent an offcut of 2mm aluminiu...

Very reasonable, single purchase, perpetual license, 2D layout for £59. Does anyone use this version, views opinions? I wonder if will release a 2024 version and when?
Thanks

" For ultimate results, you can use an end mill to open an existing undersized hole if size and roundness are critical. That is the optimum way to create the hole you desire, short of boring. You can also use an undersized center cutting end mill to open the holes, but be advised that they oft...

If the other methods don't produce an acceptable result I'll give a Diablo bimetal hole saw a try.
Thanks.

Thanks for your replies Harold and everyone else.

Charles. Have a look at, small tube amp build - step by step (2 - Chassis) https://www.youtube.com/watch?v=tHILcE6iEv4 01:12,08:48 and 09:15 Ps. I ordered the 14 inch x 14 inch sheet of aluminium, delivered a couple of days ago. Was a 400mm x 400mm sheet, asked for the offcuts so could practice bend...

I saw someone drilling 19mm diameter holes using a Forstner bit, successfully in 2mm aluminium. I want to do the same but in 3mm aluminium. I have a 3/4 Hp pillar drill which has a speed range of 195-3645 rpm. Do I change the speed for different size bits? Any advice on technique, method,use of cutt...