Rookie questions

Please bear with me, I'm almost ready for retirement, I've had 45+ years of *limited* experience on manual lathes/mills, but never as a full-time job so I consider myself a mix between a total rookie and novice. So please be kind to me, I'm still learning....

We're a small engineering company and have problems finding shops to machine prototypes in a timely fashion. So to expedite R&D time we purchased a used Ganesh GT1323 CNC lathe. All of our work is small parts, 2" dia x 6" long or less, a mix of aluminum and some stainless steel. Most of it will be a one-of-a-kind, but we have a few low volume parts we will make on it.

1. One of the low volume parts (less than 100/year) will require a #1 Morse taper hole (thru hole) in both aluminum and SS303. Would it be better to use a ream or a boring bar to cut the taper? The small end of the hole is only .369" dia. so it would have to be a small boring bar. If I use a ream would I drill it slightly less than the small size and ream the rest?

2. I need to cut a M6x1.0 male thread on several aluminum parts but need to have a tool that is very narrow and will need to cut the threads on the chuck-side of the part. The right-hand threading insert holder we have will not work for this operation so I'll be purchasing a left-hand threading tool but would like to have it as narrow as possible to minimize waste and have minimum overhang out of the chuck. I see some cut-off tool holders that say they can also thread and appear to be narrower than a threading tool holder. Any suggestions?

3. What is a good source of lathe tooling (3/4" square)? The lathe came with four Shars tooling kits and seem to hold up fine for what we do, but they have a very limited selection of tooling.

1. I've never had to cut a morse taper before. That being said, the taper reamers seem like a good option. Though, I'd be a little worried about the reamer chattering when cutting stainless. You'd just have to try it unless someone else can chime in on that. I imagine that you would drill to the 0.369" diameter or smaller, as you say, if having that 0.369" diameter is critical. Actually, drill as large a hole as you can get away with to help yourself out.
Boring it is another option. You would need a 5/16" carbide shank "minimum clearance" bar to get that depth to diameter ratio. It could be done, but you'd have to take a lot of small cuts. The carbide boring bar would be a lot less forgiving than the reamer.

2. Not knowing the size and shape of your part, it's hard to recommend an exact tool. Take a look at the Vargus Slim Throat tools as I believe this might be what you're looking for.

3. Most all major brands make decent lathe tooling. Take a look at Ultra-Dex and Dorian for some more budget friendly options (that aren't made in China).

Good luck!

Either step drill the taper or rough some of it out with a boring bar that you can get to. Then finish with a ream. If you get a roughing ream and then a finishing one you should have good results. I often bore similar size or smaller holes with carbide bars but it takes forever since the bar is sticking out so far and you need to spin the part slowly to avoid chatter and take very light cuts.

I agree with Hardplates^ on the MT procedure, for tooling I would check with your local suppliers. That way you have options for more expensive tooling when required and offshore when trying to save a $... more importantly being able to run out and pick up tooling in a pinch can be a lifesaver at times.

Boy - I question the validity of a [long/tapered] reamer in SS.

I would love to hear the results.

But also - I wouldn't be lookin' fwd to borin' that either.




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Think Snow Eh!
Ox

We regularly do a #2 B&S taper about 1.25" deep in 4140. We use a spot drill and then three drills to make steps and then ream. I barely even know what stainless is, though, so I don't know if it will work there. Good luck!