Haas GT 20 First impressions

[Geof]

First impression? It is small. But it packs a large spindle bore of almost 3". We got the 8 tool turret option but went for the manual 8" chuck, slightly bored out for 2-1/4" bar work and will be adapting a 10" chuck to it for parting off discs from 2-3/4" leaded. Working area is nicely accessible for loading except impossible to use a chuck key in the conventional above the chuck position. A bracket bolted to the headstock with a hole to align the chuck key and hold it horizontal solved that problem. It is not going to look this clean for very long.

[Ken_Shea]

Nice Geof,
I would love to have a GT-20, very nicely laid out shop as well, lots of room, clean, well lit and lots of Haas

Ken

[miljnor]

Nice shop man!

I havn't been keeping up on the newer Haas's! I haven't even heard of the Gt-20.

By the way what is all the air conditioner like ducting for? Fume control?

[Geof]

The GT came out last year. Yes ducting is central mist collector system.

[Geof]

I did say it would not stay clean for long. This machine was purchased for mostly very mundane operations; parting discs off leaded steel round bar. Being small it is only possible to have a 5" length out from the chuck and it handles the parting out at the end perfectly. Six discs; faced, chamfered, drilled and parted in just less than 6 minutes.

Determined that the spindle bore is indeed less than 3"; 2.996" to be precise. I suppose the "spindle bore 3.00 inches" on the Haas website is technically correct; 3.00 implies +/-0.01 so they are within spec. We will have to be creative to get 3" round bar through the spindle.

Only glitch so far is the red alarm light; which lights up and stays lit up constantly no matter what the machine is doing.

[Kool Parts]

Geof,
Since I got back into race cars I havent even looked at new machine stuff in quite a while. But that little dude might just be perfect for some parts I run. That sucks about the bore size though. I do like that little bracket for the key though, cant leave the key in by accident
Gary

[Geof]

Originally Posted by Kool Parts ...That sucks about the bore size ....

That problem will be solved but don't tell anyone. The purists will be horrified at the thought of taking a long boring bar to the machine spindle bore. It will wait until the warranty expires though.

[JPMach]

Except that it would require a special built tool. Couldn't you basically gun drill with the turret doing the work?

JP

[Geof]

Originally Posted by JPMach Except that it would require a special built tool. Couldn't you basically gun drill with the turret doing the work? JP

I was going to rig up something equivalent to a line boring setup. One end held in the turret the other end supported by a bearing mounted on the big flange on the end of the spindle. I want to take out something like 0.008, maybe a bit more.

I had thought about a big hone but I have this thing about getting abrasive particles around my machines.

[JWK42]

We had to do something like that a long time ago. We mounted a pilot about .002 under the hole on the end of a long bar. We the cross drilled a hole through the far end of the pilot and mounted a brazed carbide TSE style tool in the hole with cross set screws. We let the tool protrode out of the pilot the desired amount. We secured the bar to the crossslde and turned on the spindle (very slow to start) We engaged the power feed and pulled the pilot with the tool protruding through the bore and rebored the bore to the new size. This worked on bronze material. I don't know how hard your spindle is so this might not work for you. We actual rebored a 105" long bar .062 per side in one pass. Not a very practical thing to do but we saved an account.

Edit
The chips stayed in the bore behind the pilot and were not a problem.

[Chuck Reamer]

Originally Posted by Geof will be adapting a 10" chuck to it for parting off discs from 2-3/4" leaded.

Have you mounted the 10" chuck yet, I am wondering if its possible. If you have what kind of chuck was it and did you have to do anything special?

I also plan to use a 8" manual chuck, but would prefer a 10" to get more diameter from the chuck bore.

[Geof]

Originally Posted by Chuck Reamer Have you mounted the 10" chuck yet, I am wondering if its possible. If you have what kind of chuck was it and did you have to do anything special? I also plan to use a 8" manual chuck, but would prefer a 10" to get more diameter from the chuck bore.

I used a 10" Bison on an aluminum adapter plate. The adapter plate bolts onto the mounting flange for the 8" Bison Set Tru chuck.

This setup is used for machining 2-3/4" down to 2-5/8" so really good chuck accuracy is not important. I machined the adapter plate to the final spigot size for the 10" chuck on the machine and the chuck is running better than 5 thou TIR.

The spindle spends a bit longer accelerating and stopping but this has not caused any problems.