Newbie on a TL-2

[JohnJW]

I am slowly, very slowly, learning how to operate the TL-2. I don't have the skill to build my own pneumatic closer like Geof, but I've seen pictures of Mark Hockett's Royal 5C setup and that's what I ended up with.

I setup the pneumatic collet closer and I am ready to diy the spindle liner. I want to turn 1" and 1/2" aluminum bar stock and I am wondering how deep into the spindle do the liners have to extend? What about the for the 1" diameter bar? The draw tube is only 1.06" ID.

I don't know if this is doable, but I plan on building a support stand, kind of like Haas's bar stock feeder but without the feed mechanism, so I can use longer bar stock, ie 4'~6' bars. The bars will be resting in a obtuse V groove supported on roller bearing.

Also, the according to the rpm formula, at 1" diameter and ~600sfm for aluminum, I should be at ~2200rpm and if I go down to 1/2" dia the rpm requirement doubles but the spindle max out at 3500rpm.

My limited machining experience so far are all with milling aluminum so I did not have a fear of high spindle rpm until I read the horror stories of unsupported steel bars whipping and bending and saw the videos on youtube of work pieces flying off. Now I have an almost unhealthy fear of the lathe spindle. Last night I was running G97 at 1000rpm and that was kind scary.

The Royal 5C pneumatic closer has a max operating rpm of 4,000 and right now I am turning small pieces, 1" diameter, 1.8" in length with ~.5" in the collet. Is it safe for me to use G96 and slowly increase to max speed? How much stock should be clamped in the collet to be safe?

What if I switch to continuous bar stock 4'~6' long. Is it safe to go up toward 3500rpm with half of the bar handing out the back of the closer but supported by support stand,

thanks,

John

[tennsmith07]

well i cant give you much advice on if it is safe to just have .500 in the collet being i dont know your speed and feed rates but i do know i would not have more than 1' of material hanging out supported or not i i dont run anything longer than 6' but my lathe is pretty large and no more than a foot ever hangs out

[Geof]

So many questions.

First answer/comment: Do not, I repeat do not run the machine with un-supported bar stock protruding out of the end of the spindle.

For small diameters such as 1" or less it is even necessary to support the bar inside the spindle. Although of course the collet draw tube does provide this support. If you are using a chuck and the bar is in the almost 3" diameter spindle bore, it will likely deflect off to the side at high rpm and be badly out of balance.

Initially you should stick to bar lengths that do not protrude beyond the end of the draw tube.

Minimum length to clamp in collet for best grip should be about equal to or greater than the diameter. You can get by with less but not if it is sticking out much. Gripping on 1/2" for 1.8" sticking out is on the borderline and you should stick with small depth of cut (0.03") and light feed (0.005 ipr) until you have gained a bit of experience. Gripping more than about a length of one diameter does not improve thing because the collet gripping length is about that.


Building a support stand for longer bars is a good idea but to have something 1" diameter spinning at 3500 rpm while it is sticking out over three feet (i.e. a bar six feet long) needs a substantial support. In addition it is not really adequate just to run the bar through a bearing that is mounted on a stand. With this arrangement the bar can whip between the support bearing and the end of the spindle and be just about as hazardous as an un-supported bar.

The safest is to have a carrier tube supported by bearings at each end mount on a sturdy frame either bolted to the floor, secured to the end of the machine and just standing on the floor or heavy enough that it will stay put just from its own weight. Think several hundred pounds.

The bearings for the carrier tube need a bit of adjustment, or the frame needs adjustable feet to the tube can be aligned parallel and concentric to the spindle within 0.01" or better.

If the largest size bar to be run is only 1" the tube itself only needs to be a bit larger than 1" inside but it needs a substantial wall thickness (1/4" or so) so the tube does not tend to whip between its bearings.

It is also necessary to devise some sort of connection between the spindle and the carrier tube so it spins with the spindle and this might need some creativity with the Royal collet closer.

[JohnJW]

Okay, long protrusion out of the spindle is a not a good idea and building a support stand is none trivial. . . . I got it.

. . . and Goef, I have a few more questions again. . .

1. I was having problem with the closer not holding the stock tight enough. . . turn out I just screw the collet in a couple more turns and that' it. However, how far should I screw the collet in? All the way in? back off a turn? just enough to hold the stock tight?

2. I read about coolant leaks on TL2 with enclosure and now I have first hand experience with the hospital gown inspired design. I got puddles all around the lathe and a nice 4' splatter pattern out the back, and this is with me cutting an inch from the spindle nose. . . I will be searching the forum archive to see how you position the acrylic/Plexiglas panel on your TL2. Any area I should pay particular attention to? and is there a better way to deliver the coolant onto the cutting tool? Right I have to manual adjust the single coolant line. Mark Hockett's coolant through turret mod is beyond my current ability, but that is a nice mod.

3. I remember seeing how you and others mount multiple tools on the tool turret. How do you clear the servo box to the rear of the turret when you do a tool change? I want to drill and tap. if I can mount them side by side, I can save a tool position, but it looks like there's only about ~1" of vertical clearance from spindle center to the top of the servo box.

4. I tried the G96 and slowly ramp up the rpm to 3200. While running it I noticed the collet closer does get warm to the touch and while I can't see the vibration, I can feel it when I touch the closer. Is this normal? By the time I started using G96 the bar length was around 6 or 7 inches and I'm not using a spindle liner. Is that enough to cause the vibration. I do like the collet closer. It's pretty consistent. After the parting cut, I just pull out another 1.5" , close the collet, and repeat.

[djr76]

answer to #1 - Usually collet chucks have a dog nose set screw that rides in the slot parallel to the collet itself to keep it from rotating in the chuck. Turn the collet till snug, then back it off till it lines up with the cross hole in the chuck body.

answer to #4 - Id use a bar liner for support.

[Geof]

#1.

The Royal collet nose has two holes for the locking screw that goes into the keyway in the collet. To install the collet with the air valve in the open position screw the collet in until it just makes contact with the taper. Then back it off and stop as soon as the keyway is inline with one of the screw holes. Insert the locking screw in this hole.

If the stock still slips check that the air pressure is at the maximum allowed for the closer.

#2

The factory supplied coolant nozzle setup is almost useless. I drilled and tapped two holes into the base of the tool turret and bolted on a bracket that goes up and over the turret. There is a manifold attached to the bracket with four coolant nozzles so I can aim one for each tool. There is a picture in one of the threads I have linked showing this.

One of the links also shows my coolant screens.

#3

Yes very little clearance. See Post #43 in the link near the bottom below.

#4

If you can feel vibration only on the collet closer attached to the end of the spindle it is probably just that part wobbling slightly. The Royal collet closer is interesting because the air cylinder operates the drawtube through some big thrust bearings. The tube has to rotate of course and the air cylinder is stationary. Probably that is why it gets warm and there is no reason to worry unless it gets to hot to hold your hand on for a minute or so.


It is a good idea to use liner tubes because not only do they stop the bar whipping when it is long they also keep it better aligned in the collet.

Here are several links to threads or posts I have done on the TL2

Easy Turn Chuck Handle on TL2

homemade pneumatic bar feeder

http://www.cnczone.com/forums/haas_l...s_coolant.html

TL bar feed design.

http://www.cnczone.com/forums/haas_l..._up_slack.html

Tool Shift for gang tooling

Whoops (see post #43)

http://www.cnczone.com/forums/haas_l...find_home.html

TL-2 Noisy Spindle

[JohnJW]

Goef,

Thanks for the links. They will give me some ideas on how to modify the TL-2 enclosure and coolant line. The enclosure and coolant option for how much they cost relative to the machine and how they actually perform, is really quite a crummy deal, but I guess they're better than nothing.

Another thing I discover is that the TL2 doesn't have a low air pressure alarm. The only warning is the grinding noise from the turret as it try to change tool. . . . ouch.

Do you any suggestion on how I can make the spindle liner for the 1" bar stock in the 1.06" draw tube? I thought about machining it out of plastic rod sections, but the wall thickness will be around .03", is that doable?

John

[Geof]

I agree the enclosure is a bit makeshift but I guess that is mostly because the machine was originally conceived as an open design. In addition to my baffles and deflectors to limit the amount of coolant that escaped I also have large trays under the machine to catch drips.

I also have heard that horrible noise when you attempt a toolchange without air. Scared the hell out of me the first time.

You may also get it if you have a long tool in the turret when the machine is home and you zero the tool changer. The tool will probably hit the tailstock.

Which reminds me; I have a parking program that I run at the end of the day. This takes the Z axis to Z-4. in machine coordinates and rotates the turret to tool position 1 before I turn the power off. Then when I power up I zero the tool changer first and it is well clear of the tailstock, then the Z and finally the X.

I also run the same program in the morning because it includes a short warm up cycle to get the grease distributed in the spindle bearings. The machine makes much less noise when I then run at high speed. I will copy it and post it if you like.

It is hardly worth making spindle liners for the 1.06 bore on the draw tube but it might help a bit. The least expensive way might be to get some PVC water pipe or conduit. Turn and bore short lengths and slide them into the draw tube.

[JohnJW]

Thank Geof,

I made some simple acrylic coolant shielding base on your images. I managed to stop coolant from splashing out behind the spindle and caught most of the coolant splashing out the wide gap pass the tail stock.

I still have a pretty big coolant leak somewhere in the the back of the machine, but they are hard get to. The enclosure was pretty good at keeping me out but not too good at keeping the coolant in.

I noticed one of your splash guard is mounted directly to the saddle casting and spans the entire width of the machine. Currently I mount my 1/8" acrylic shield to the turret motor mount. Because the of the x travel, my splash guard only catches half of the backsplash. The other half splashed toward the back of the machine and escape out the large gap.

It'll probably be a while before I work up the nerves and skill to drill into the saddle casting. But just in case, how do you drill and tap the saddle casting? Do I have to worry about inadvertently drilling into anything important?

and if possible, can you post your warm up program? thanks.

[Geof]

I will download the Warm Up program next time I have the machine running. (If my old brain remembers)

For the splash guards attached to the saddle I did not drill into the casting I used the holes the apron was bolted to. I took the hand wheels off my machine because I never use then and then when I speeded up the Z axis rapid I had to take off the apron with the gear running in the rack because it gave too much drag.

In the last picture showing the splash guards you can see the big length of 1" x 2" cold rolled steel that is bolted onto the apron mounting holes. Then there is a length of 1/2" x 2" (or 3") which runs across the back of the saddle. This is bolted to the other piece with a spacer block. This way the guard stays still when the X axis moves.

I still have a bit of a leak out the back somewhere and this is what I catch in my drip trays.