RF-30 plus stubby drills equals Nirvana?

[WCraig]

It comes up again and again how moving the head on an RF-30 style mill-drill is such a pain because of losing positional accuracy.

So don't do that!

I hope this thread might collect some of the strategies people use to avoid having to change the height of the head. For example, use stubby drills instead of jobber length. My 1/2" ∅ stubby is 4 inches long versus 6 inches for the jobber drill*. Being shorter and less flexible, the stubby often doesn't need a spot drill to start. Even if it does, it is short enough that one set up can do both the centre drill starter and finish the hole with the stubby.

Even better, use actual spotting drills rather than a centre drill to start. Spotting drills are generally close to stubby length so the head can stay in one position for both operations. Spotting drills are also fine for chamfering in many cases so again you can avoid switching to a really short chamfer bit.

Another common situation is where you want to set up a piece and drill some holes and mill some features without moving the part. The obvious approach is to switch between a drill chuck for drilling and collets for milling. The trouble is that a typical 5/8" drill chuck often eats up 3 to 4 inches of the vertical travel. One way to avoid that problem is...don't use a drill chuck. Mount your drill in a collet, if possible. Again, stubby drills are close enough to the length of common end mills that you will have sufficient travel to do the required operations. Another option is to use a smaller drill chuck when appropriate. A 1/4 or 3/8 inch capacity chuck generally occupies a bit less vertical height and may keep you within the Z envelope.

So, what do you say? Any more strategies on getting stuff done without having to reposition the head on an RF-30?

Craig

* my stubby 1/2" drill has 2 inches of flute length. For most of my projects, the stubby is sufficiently long but, from time to time, you're going to need the extra length of a jobber (or longer) drill. Can't win them all!

 

[DavidR8]

I have a few TTS tool holders one of which is a (1/6"-1/4"drill chuck) that I've been using more frequently and finding that I'm not needing to raise or lower then head nearly as much.
I have a set of stubby drills in my KBC cart but haven't committed to them yet.

 

[Manual Mac]

I have a couple each of 1/4, 5/16, 3/8 & 1/2” Stubby bits.
I actually use them quite often on my machines.

 

[MrWhoopee]

I am a huge fan of stub drills, so much so that I actually bought a full 3-in-1 set. I also shorten the shanks on my drill chucks. I have a knee mill, but it's still a pain to have to crank up and down.

 

[Larry$]

I have a knee mill but use screw machine drills (stubbies) most of the time.

 

[Cadillac STS]

I have a set that is separate and only used if really needed. That way when I need one it is more likely sharp. Have many other drill bits.

 

[C-Bag]

Somewhere early on in my research of the RF30 the big downvote was loosing register when moving the head. It was pointed out planning ahead to understand what tooling you'd need was just as important as plotting out sequence of operations. And one of the best ways was understanding what each tool does for Z height. So it became very apparent that going to screw length drills would, depending on what all was involved, make it so I wouldn't have to change height. The added benefit of getting a set of number drills, and letter drills has been so handy. I didn't have a really good drill chuck for the mill so instead of plowing $$ into a drill chuck it went into drills and complete collet sets. Money well spent.

 

[C-Bag]

I have a few TTS tool holders one of which is a (1/6"-1/4"drill chuck) that I've been using more frequently and finding that I'm not needing to raise or lower then head nearly as much.
I have a set of stubby drills in my KBC cart but haven't committed to them yet.

I've been meaning to ask you David, in one of your threads I noticed you installed one of the head guides like one of the members here came up with on your mill. Doesn't that pretty much make it so you don't lose register when raising and lowering the head? Or is it just that it's kind of a pain to raise and lower the head, or just you had adapted to not messing with the Z?

 

[DavidR8]

I've been meaning to ask you David, in one of your threads I noticed you installed one of the head guides like one of the members here came up with on your mill. Doesn't that pretty much make it so you don't lose register when raising and lowering the head? Or is it just that it's kind of a pain to raise and lower the head, or just you had adapted to not messing with the Z?

The guide works like a charm, repeatable to .001 pretty much every time.
The challenge (and it's kinda trivial TBH) is the bolts that lock the head. The previous owner wrench welded a wrench to the lower bolt but I still need a wrench for the top bolt. And the space is limited because I have my DRO display mounted on the same side as the bolts.
I may move the DRO display mount to the wall so I have better access to the bolts.
I'd love to figure out some sort of cam action thing to lock the head down.

 

[C-Bag]

The guide works like a charm, repeatable to .001 pretty much every time.
The challenge (and it's kinda trivial TBH) is the bolts that lock the head. The previous owner wrench welded a wrench to the lower bolt but I still need a wrench for the top bolt. And the space is limited because I have my DRO display mounted on the same side as the bolts.
I may move the DRO display mount to the wall so I have better access to the bolts.
I'd love to figure out some sort of cam action thing to lock the head down.

Did you ever post pic's of details of your guide? I periodically think about making something like it but my mill doesn't have the same places to attach to and I've got so many other projects I need. If I'd not already had my ways of dealing with it already I think it would be at the top of the list.