I put the crank arm on an old square taper axle and use that to indicate from so the hole is parallel to the axle. Clamping the axle in a vertically mounted rotary chuck clamped to the table is the best but a vice will do.
If you're using a drill press, once you drill the hole, put the tap in the chuck to hold it in alignment when you tap the threads. Don't use the drill motor though. Just rotate the chuck by hand to get the thread started. Once its going straight and too tight to turn then loosen the chuck, get it out of the way and finish the thread.
@SummitFever thanks, pretty much what I was planning to do, also is that your site I referenced at the beginning? if so thanks very much it's a great resource. My old man had a general engineering business for most of my life and I ended up as a fridgy so understand tapping. I probably didn't explain myself originally, but have attached a sketch of my proposed setup.
If I drill every hole in the block of whatever I can find on the table of the drill press it will all have to be in the same plane. Then bolt the crank to the taper of the cut down bb axle and set up the length. Once that's in the right place clamp the block to the table of the press and drill and tap one arm, use an extractor to get the arm off and then attach the other and drill and tap that and job done. It would probably work with a block of hardwood if I can't find a decent chunk of aluminium at the scrap yard. I have the Hozan C-401 taps with the parallel leads at the beginning so tapping should not be too much drama. I'll probably use a step drill to face the outside edge of the hole flat.
@moorey let me know what you think of the pics and what you have please?
@kip01 what BB width are the Hussefelts and what BB style, do you have any pics?
@PJO the ebay ones you quoted, are currently looking like the best choice depending what Moorey and Kipo1 come up with. I have found a "supposedly local" seller but trying to confirm if they actually post from Aus and I can get them in a reasonable time frame.
Find many great new & used options and get the best deals for 104/64BCD 24/32/42t 3x10S 170mm Aluminum MTB Road Bike Chainring Crank Chainset at the best online prices at eBay!
www.ebay.com.au