Drilling 5/8 holes in stainless.

[GILow]

Hi all,

I need to drill holes in the new chainplates but I’m having trouble finding a 5/8 drill bit capable of the job.

Does anyone know of a vendor/manufacturer of something suitable?

Matt

[dlj]

Mcmaster Carr has several options. If you don't have a tapered chuck, they do have 1/2" turned shank drill bits. they aren't cheap.

https://www.mcmaster.com/products/dr...nk-drill-bits/

dj

p.s. I see you may be in Australia - I don't think they ship there, but I don't know.

[deblen]

Dormer HSS https://www.dormerpramet.com/us/en_US/

[Orion Jim]

Originally Posted by GILow

Hi all,

I need to drill holes in the new chainplates but I’m having trouble finding a 5/8 drill bit capable of the job.

Does anyone know of a vendor/manufacturer of something suitable?

Matt

I had decent luck with cobalt coated drills but it would be well worth letting a local machine shop (or whatever the equivalent business is called down under which employs machinists) since they have already invested in the cutting tools and equipment necessary to perform such work. It’s so easy to work harden stainless and go through drills needlessly that it’s cheaper to let the pro’s take it on.

[massnspace]

Start with a super small drill….then just keep using larger and larger bits until you get to 5/8”.

Takes a long time but works. I just did this to make a stainless plate extension for an anchor roller….1/2” final holes, but same idea….and use cutting fluid.

[Onthewater222]

I’ve had great success using water in a spray bottle to keep the bit cool and drilling slow, even with non cobalt bits

[Peregrine1983]

Cobalt tipped bits. Use ample amounts of drilling lubricant like Mach Blue Goo. Go super, super slow with lots of pressure, and put a fan on it while you work to keep the drill and the work piece cool.

You'll be shocked how the steel just flakes away.

[Wotname]

Surely you can get a 5/8" HSS twist drill with a reduced shank (1/2' or 13mm) in Adelaide (Bunnings etc).

However if you want something more upmarket and can accept a 16mm hole (i.e. 5 thou bigger than 5/8") and assuming the thickness of the chainplate is less than 12mm, then this TCT hole saw will do the job (and is available on line in Oz) https://qualitycuttingtools.com.au/p...th-12mm-d16mm/

Of course you will have to buy the arbor etc.

I haven't searched for a 5/8" TCT hole saw but I am sure you could find one.

If you are using hand tools, the TCT hole saw is a better option than a HSS twist drill but if you have access to a pedestal drill press, the HSS twist drill is all you need.

[kayakerChuck]

I second Jim's comment above.

Unless you are familiar with working with it and have the proper tools, have a shop drill the holes.

At a minimum, you'll need the drill bits, good workholding, and a decently powerful pedestal drill press or vertical mill.

[Bowdrie]

Most any of the more-or-less "normal" drill presses on the consumer market have too high of spindle speeds even at their lowest setting, and just don't have enough quill pressure unless you basically put your weight on the handles.
Let alone the rigidity to hold the workpiece immovable.
Get a shop to do it, they'll use a milling machine or a heavy duty geared-head drill press, probably with a spray coolant/lubricant device.
It's worth it.
If you're concerned about a shop getting the holes exactly where you want them then drill small. (~1/8",) where you want the holes.

[skipperpete]

Originally Posted by GILow

Hi all,

I need to drill holes in the new chainplates but I’m having trouble finding a 5/8 drill bit capable of the job.

Does anyone know of a vendor/manufacturer of something suitable?

Matt

Trefolex ( the magic cutting compound) and a drill speed as slow as you can get. I’ve also used a carbide step drill but only on 4 or 5mm plate, I’m thinking your chainplates would be thicker than that. I had good success with a masonry drill, cemented carbide tip, if you sharpen one of these the same as you would an ordinary drill bit, you can bore into just about any steel. Use a diamond angle grinder disc though, sharpening a carbide bit doesn’t work on a conventional grinding wheel. I didn’t invent the “carbide drill for steel” idea, I saw them on a telemarketing channel ….. “buy now and get a second set completely free”…and decided I could make my own.

[GILow]

Hi all,

Some great responses, thank you all.

Not often I envy our cousins in the US, but it is true that you do have a way better set of consumer options than us poor antipodeans.

I rarely advocate the “call a professional” approach but I’m close to conceding defeat in this instance. Bloody annoying really because I’ve got a fancy 1/2 inch drill bit that goes through the stainless fine with my existing setup of a budget friendly drill press and Trefolex cutting compound (tips hat to Skipper Pete). But the manufacturer of that drill bit (Sutton) seems to stop at 1/2 inch.

I got a call from a wise engineering type today and I’ll try his approach with the existing gear. But I’m not all that optimistic.

I ended up asking a CNC outfit I contacted over a year ago to refresh their quote, I think I’ll end up going down that path at the end of the day.

Thank you all again.

Matt

[GILow]

Originally Posted by skipperpete

Trefolex ( the magic cutting compound) and a drill speed as slow as you can get. I’ve also used a carbide step drill but only on 4 or 5mm plate, I’m thinking your chainplates would be thicker than that. I had good success with a masonry drill, cemented carbide tip, if you sharpen one of these the same as you would an ordinary drill bit, you can bore into just about any steel. Use a diamond angle grinder disc though, sharpening a carbide bit doesn’t work on a conventional grinding wheel. I didn’t invent the “carbide drill for steel” idea, I saw them on a telemarketing channel ….. “buy now and get a second set completely free”…and decided I could make my own.

Particularly fascinating idea. Regardless of how I tackle this project I’m going to give this a try. Thank you.

[coopec43]

Matt

5/8 in HSS drills are easy to find.

BUT to drill SS you need a very low 300 RPM drill press. And I agree with Bowdrie that drill presses that we would normally buy are far too fast. Additionally you need a LOT of down force otherwise the SS will work harden (as others have mentioned) Because my chain-plates were already installed in the yacht I couldn't use a drill press so I levered the big old drill down with a length of 3X2 timber while my BIL worked the drill.

On a few occasions I have work hardened the SS (because I couldn't exert enough pressure) so I sharpened up a masonry drill and completed the hole. (Masonry drills are tungsten tipped)

https://www.youtube.com/watch?v=burt-941AXQ

[Lepke]

To get nice holes in stainless you need either a hole punch or a hole cutter.
Drilling stainless requires a stainless or better bit, lots of cutting oil or water for cooling and a slow speed. Best to start with a small hole. If the drill bit gets hot it looses its' temper and goes dull fast. Otherwise take the stainless to a machine shop.

Cutter shown is about $9 on ebay. Didn't check AU ebay.

https://www.ebay.com/itm/16622181849...Bk9SR8y7tdnpYw