A quick look at the Drill Service website shows a long series 1/2" endmill with flutes that are 49mm long. That's almost 2". It doesn't matter if you go a bit deeper than the flute length, provided that you've cut the upper part of the slot to full length first.

I'd probably go for a carbide cutter, as they're stiffer than HSS. I'd rough out as much of the slot as possible with drills a bit under 1/2". I'd also use a centre cutting tool and plunge cut at the ends of the slot first to get a clean finish.

Andrew

"I need to machine a slot .5" x 2.9" thru in a steel block 2" deep.

I think the longest end mill is a long series which can cut to 1-1/2" deep, so I

can't break through."

Look in J &L advantage April 2016 page 10 .
12 mm mm HSS-e flute length 53 mm JDCAA-22112K uncoated
@ £8.99 +vat or TiCN coated JDCAT-62112M @ £12.60 +vat,
Both 4 flute centre cutting.

There is an additional one off per order postage charge with J & L .

John

Hi Cameron,

I've never tried to machine a narrow'ish slot quite as deep as that but if you know anyone with a shaper – then a tool similar to a heavy duty parting-tool might well manage it and is the simplest solution. A bit like 'linear' parting. I also use slitting saws for deep, very thin slots but my s/saws are mostly only 3" diameter, so wouldn't handle this case. I do have larger diameter side and face cutters (for my big horizontal mill) that could probably be used but obviously this is a very much meatier machine than your smaller vertical mill.

However, I think you should look at these alternatives (to using a long reach mill) as although it wouldn't be done "in industry" – anything that works in practice is usually OK by me. In this case, either a large diameter saw or face cutter held in a suitable mandrel would probably work. Whatever you use it would have to be done in multiple passes of course, just nibbling away at the work piece – very light cuts but I assume time is not an issue for you in this case.

Just a thought.

Regards,

IanT