[Kludge]

Hi,

TM6 vs TM8 Selection Help wanted.

I will be making parts primarily for my own business.
At least 12 different parts all in small lots, typically 10 to 50 parts per batch.

The highest volume part is 1.5" Delrin/Acetal, the typical parts range from 5/8" diameter Stainless to 2.0" 4130, low volume parts are 4.5" 4130 and 6.5" diameter 6061. Most parts will involve face, profile and bore some with ID/OD threading see list at end of this post

I'm coming from a background of low HP manual lathes with an 1800 RPM maximum, so I don't have any experience with CNC lathes. I do have some g-code experience with a low HP CNC mill.

I originally priced up the Haas TL-1 and TL-2 and talked with a few folks who have them. My conclusion was that by the time I had configured up the Haas machines in a ready to work configuration, I could buy a Hurco Slant Bed TM6 for basically the same money. The TM8 is $10,000 more.

I have studied the specs for the TM6 and TM8.
The significant differences to me are:
TM6 6" chuck, 1.75" bar capacity, 6000RPM, 3/4" tooling, 12 tool turret
TM6 8" chuck, 2" bar capacity, 4500RPM, 1" tooling, 10 tool turret

TM6 fits the budget better
TM8 chuck would handle the larger but low volume stock easier.

How important is the extra RPM range of the TM6?
Or will I regret being limited to 4500 RPM on the TM8 for the smaller parts.

How well will I be able to chuck a 6.5" piece of raw 6061 on the 6" chuck?

Should I budget for a Quick Change chuck jaw (or Chuck) system?

How repeatable (TIR) is swapping soft jaws on a power chuck? (I would like to avoid a re-bore of soft jaws on every setup.

How repeatable (TIR) is swapping the power collet closer for the power Chuck ?

List of materials and raw stock length.

Highest Volume parts (batches of 40 to 100)
1.25", 1.5" and 1.75" Delrin/Acetal profile and bore less than 2" length

Medium Volume Parts (batches of 10 to 25)
5/8" and 3/4" diameter SS 303 less than 2" in length
1" diameter 4140 ID and OD threads
1.25" 1040 ID threads 1.4" deep
1.5" 4130 less than 4" length (precisely parted tubing)
2" 4130 5" long 5/8 OD threads, profile from 5/8 to 1.9"
2" 1040 5" long 5/8 OD threads, profile from 5/8 to 1.9"

Low volume parts: (batches of 4 to 8 parts per batch)
4.5" 4130 2" long
6.5" 6061 4" long, Deep 1." diameter bore, (initial profiling will quickly reduce one end to 5" and the other to3.5", could rough down on end on mill prior to chucking)


/Frank

[68sixspeed]

I'd think TM8; I have a TM6, great machine, but one reason we went that way is that we do a lot of small work with it, 3/8"od, smaller where the high rpm is needed or at least makes life easier. We've also done some 2-1/2 and 3" dia steel rollers no problem too. We've never pulled the chuck though, soft jaws, or a master-jaw setup to use 5c collets in the 3 jaw chuck. It's a lot faster changeover and it saves the risk of cross threading the chuck or collet unit when swapping.

[Kludge]

I'd think TM8; I have a TM6, great machine, but one reason we went that way is that we do a lot of small work with it, 3/8"od, smaller where the high rpm is needed or at least makes life easier..........

Hi 68sixspeed,

I appreciate your response. Your advice confirms my thinking.

I actually had a chance to see a TM6 in use locally and talk with the machinist that programs and runs it. He really likes the machine and does all the programming in the conversational mode (he has many years of experience programing their other lathes in G-code).

I've decided to go for the TM8, it's a bit painful on the budget, but I'm not expecting to need a larger capacity machine in the future, as the TM8 is rated to swing a 12" diameter part (carefully I assume). I believe it will give me the most flexibly in the future while easily handling all of my current parts.

If come to a point in time that I need to turn a large quantity of small diameter parts, I'll look at a 5C gang tool machine.

I plan to start with soft jaws, then look at a the master jaw system for 5C like you have and the J-LOC system.

Now I need to find a 1" shank tooling setup for this machine that will give me good flexibility without having to change out most of the tools in the turret (I.E. just change the inserts for the different materials).


/Frank

[68sixspeed]

Contact any of the major tooling places - they will likely lend a hand on tooling; I had MSC in and they brought the Kennametal guy, spent a few hours going over tooling, made a package deal for a better price too. Usually if you buy enough inserts they will give or practically give you the tool holders.

[HurcoLatheGuy]

Guys,

I work for Hurco and found a company with a terrific tool holder that's extremely quick to change out inserts, e.g., going from one grade to another for different material. We have no affiliation with them other than I saw them at a show and they gave me a few tools to try. They work great! I've done heavy turning with them and no problems whatsoever.

Axian Technologies, Click-Change tool holders. www.clickchange.com