9x20 Lathe question

[ccm]

Ok, I'm puzzled with this, maybe someone can shed some light for me. I have the Enco 9x20 Lathe, and I'm looking to swap out the 3 jaw chuck for the 4 jaw that it comes with, yes granted I've read all the reviews out there that it's not the best unit, or sometimes can be a real bear to dial it in at first, but I'm trying to turn down some dies for a tubing bender, and I'm using 5.5 inch round solid stock, so I need to use the larger chuck. Here's my dilemma....how the hell does this come off ???? I've looked at it for hours, and can't for the life of me figure this out, plus I'm fairly new at this, and don't want to damage it doing it the wrong way.
Can someone point me in a direction on this please ?....

thanks in advance!!

-Arthur

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[HuFlungDung]

Hi Arthur,

Most likely, it has a threaded spindle nose. If you have both chucks, or a faceplate, just look at the back side of one of them to find out

They are a right hand thread, if it is a threaded mount. This can sometimes get pretty tight. The method to remove, is to first shut off the power to the machine, since you do not want it to start accidentally while you have a wrench on the chuck.

Engage the back gear and the direct drive gear at the same time. This locks the spindle up solid so you have something to work against when you try to loosen the chuck. Take a large wrench and adjust it to fit one of the jaws of the chuck and pull down on it, rotating counterclockwise. As soon as it is loose, it should come off easily.

Take plenty of care of your spindle nose threads and the shoulder at the back of the threads: this is what determines how true your chuck will run.

[lsfoils]

Hi CMM,
Did you get the chuck off? Just wanted to mention that some of these smaller lathes have a set screw on the shoulder of the mounting plate which must be loosened before trying to unscrew the chuck. You will have to back the set screw off quite a lot to clear the mounting threads.... also, I suspect that your machine does not have a back gear. In this case, open the belt cover door and hold onto the largest pulley on the spindle. If the chuck is really tight, place the chuck key in the chuck and use a RUBBER OR WOODEN mallet to tap on the key. If you use a steel hammer you could break the chuck and/or key off in the chuck. And when you put a chuck on a threaded spindle ALWAYS get it as tight as you can. Its seems backwards but if you leave the chuck a little loose you will loose your regestration (accuracy) and the machine will tighten it onto the spindle for you. This will make it very difficult to get it back off... Hope this helps. -Doug

[ccm]

Well after looking for the back gear, and the direct drive gear for a little while, I realized.... that there must be an all gear drive version of this beast running around. ( blonde moment ) my bad.
Anyway, this has two drive belts, one from the motor to the main driving pulley, and one from the drive pulley to the spindle shaft ( powering the lathe chuck ).
The best I can come up with is: use the extra interchangable gears that they give you to lock up the rest of the gear box. But I'm concerned with wiping out the delrin gear in the process.
Anyone else with this same lathe ? how do you go about changing chucks ?

-art

[HomeCNC]

I have the Enco 9x20. When I remove the chuck I just remove the screw from the side of the spindle. Then I find a rubber hammer and with the chuck wrench in the chuck I use sharp blows to the wrench in the Counter Clockwise direction. About two or three of the wacks with the rubber hammer will loosen the chuck without the need to lock up the spindle.

[ccm]

Okay...... any other suggestions on removing this chuck ?
I tried your method HomeCnC, but it wouldn't work either..... I even went to the point of holding the spindle pulley on the gearbox, and the only headway I made was loosening the pulley on the shaft......the chuck, she won't move sir.

-art

[lsfoils]

Hi CCM,

Wow, thats no good. A couple of questions:

1. Is there a set screw on the shoulder just behind the chuck? It would be right next to where the chuck visually touches the spindle.

2. Is there more than one set screw along this shoulder?

3. Are there 3 bolts or three nuts on the back of the chuck to secure the chuck to the face plate? If you see nuts you may find that your "back plate" is an intregal part of the spindle and the only way to remove the chuck is to remove the nuts. Some smaller lathes are produced this way. If the back plate is not part of the spindle you will see a definate line and change of color between the plate and the spindle.

4. Can you post a photo? Might help to determine what style of mount you have if it is not a threaded mount.

Let me know what you find out and I will be glad to share any info I can on it. Doug

[HomeCNC]

WOW! someone or something really put that chuck on thight!

Isfoils: He has the same machine as mine. There is only one screw on the side of the spindle with a clip that needs to be removed before the chuck can be unscrewed.

CCM: did you buy this machine new or used? I take it that you have never had the chuck off this machine.

Could there be any rust on the threads? Maybe spray with anti seize and let it soak for a few hours.

You can remove the spindle from the bearings and try to heat the spindle and chuck and then place the spindle in Ice water to shrink it and then try to remove the spindle from the chuck.

That's all I can think of for now. If and when you do get if off, I can say that when you place a chuck on the spindle, do to the weight of the chuck don't spin it fast and let it slam into the stop collar. You will have the same problem again.

[HuFlungDung]

If you want to try the heat solution, I'd suggest that you simply take the chuck off its backplate, then, heat the rim of the backplate with a ordinary propane torch. It may take a few minutes of heating to allow it to get hot enough in the center to expand.

Do not try to expand the backplate by heating only around the center of it. The outside rim will act like a vise, and this will not allow the center to expand in a direction that will give you clearance.

You should attempt to heat it as rapidly as possible, to maintain the highest differential in temperature between the spindle nose and the backplate. You could even help keep the spindle nose cool by putting a wet rag inside of it.

You are still going to have to "hit it" to break it loose, even with heat. You can improvise by bolting a piece of flat iron to the chuck backplate. Make it as long as possible, and use a 2 or 3 lb hammer, no use working hard

You will have to find a way to adequately lock the spindle up solid, how you would do this without a backgear, I don't know. You don't want to break any gear teeth, so maybe you can provide counterforce on the outboard end of the spindle with a pipe wrench, or something, at the moment of impact.

[lsfoils]

Hello Hu,

Jeff has some pictures of an arm attached to a gear on the back end of the spindle on his web site. Maybe this could be used with your idea to maximize leverage? Doug (off to work, hi ho...)

[JOE65]

cutting torch?

[ccm]

HomeCNC, it worked it worked your idea of the rubber mallet and knocking it loose finally worked. It ended up with a friend of mine doing the hitting, with me holding the spindle pulley.
What a disappointment though, all that to get the freakin chuck off, to mount the Larger chuck, only to realize, that it's next to impossible to get the workpiece running true in the chuck...... I spent about an hour on it, then put the other chuck back on out of frustration of trying to get a piece of 5.5 in dia. 6061 mounted in the large chuck.
Any recommendations on a nice large chuck that won't break the bank ?

thanks to all for your suggestions and ideas!!

-arthur

[HomeCNC]

This is why I got the 6" Bison chuck and blank back plate to mount it. I also needed to hold larger things and the 4 jaw is crap! I believe that now you can get blank back plates with the metric thread for the 9 x 20's. I had to single point my threads. See my web site on how I mounted the bison chuck.

Just to note: The bison chuck is not too expensive and is of good quality. I really like the reversable jaw teeth that you take off with bolts not remove from the chuck.

[Alan T.]

Even if you can get the chuck changed, 5.5in stock is "ALOT" of metal to turn on a 9in lathe. I question if the machine is capable of turning the stock without damage to the lathe, motor ect.....
I have turned 4in leaded steel on my 9in lathe and it did ok but I would not have tried anything larger. I would certainly recommend a cautious approach.

Alan T.