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Spindle liner extensions

Ianagos

Stainless
Joined
Sep 23, 2014
Location
Atlanta
Looking to get some spindle liners for my machine and I’m curious as to how far out the back of the spindle they can be extended. I got a quote from trusty cook and they said 4” max. But those are plastic.

My machine has a 52mm spindle bore and the drawtube is only 30.75” long. There is about an extra 4” by the time it gets to the front of the jaws or collet Chuck though. Basically I can fit a 36” bar no problem as it sits.

I would really like to run 4 foot bars though.

Can the spindle line be extended say 10”?
That way with my part extending into the machine a few inches practically nothing sticks out the back of the liner. I would like 11” extension as then I could just make a 1.75” liner and use a set of haas liners I was planning on purchasing as they are 42” long

Whether I extend them or not I got .109” wall tube .030” over size for all my common bar stock. Got 10 sizes and it ran me about $300. For 48” lengths. I figure I can make the biggest first and work my way down one at a time.


So what are the thoughts?

Is .109 thick stock heavy enough wall?

Is 11” too much extension?

Will making my own be a terrible idea?

Should press the collars on or weld( figured welding would distort the tubing. May just use bearing retainer.)

Figure it will take me a day tô do and a full set would be over $3000 so I’m still making sop rate.
 
I talked to someone at JF Berns about this, but I can't remember what they said. I think they mentioned a limit that OSHA allows. They make spindle liners and extended liners. I think it would be worth a call to them to see how much longer they think you could extend out of your spindle.
 
I would think it’s more a length/dia ratio. I wouldn’t have an issue sticking out 10” if it was 1-1/2” liner, but I don’t think I’d be comfortable if it was a 1/2” liner.
 
I dont know the company name, but they make steel spindle liners. They advertise they make an extended version, perhaps you can check out the website and use their recommendations as a starting point?

Charles
 
I will be designing a seriously heavy weldment with many large anchor bolts into the concrete floor. Using 10" castors like a steady rest. Plan is for castors to almost touch the extended liner.
I asked the operator about a half moon punch through a .75 thick press board wall panel. He said it happened when he turned around with a 2" bar of acetal, 60 inches long. Sure, turned around like some Ninja fighter? That does not explain the peened over corner of the roll away toolbox parked next to the back of the lathe.
My guess he heard the lathe finish a 2" bar 60+", grabbed another and stuffed it into the spindle. Then he walked over to the control to open the chuck, saw that there was a stub long enough to make one more part. Set counter to 1 and green button. Then he shit himself as bad things happened.
My guess is that the tool chest took a serious hit that launched the bar. I'll confront him with this Monday.
 
Called jt burns and they answered and sent me to a guy that would help and he didn’t answer. Left a voicemail and didn’t hear back all week.

Was planning on buying one from jt burns and making the rest myself but they don’t answer or call back.

Figure I’ll save a few pennies making them all myself.

Also I may make it to where the smaller lines fit inside say the 1.75” liner that way they have lots of support.

Or I can order up a special thick wall 2” of pipe with 1.5” bore and use that as the “master” liner.

The haas liners I was looking at are all plastic and fit in a 1.75” liner.

For now all I really need is a 1.5” and 1.25” liner
 
I have thick wall aluminum tubing for a few liners. Like really thick wall and use outer rings to keep it centered, and inner acetal bushings to keep rod centered. Be aware that very thick wall aluminum may not have the "bore" very well centered on the OD. Not feeling it to bore out a 48" "tube" to center the bore.
 
I have thick wall aluminum tubing for a few liners. Like really thick wall and use outer rings to keep it centered, and inner acetal bushings to keep rod centered. Be aware that very thick wall aluminum may not have the "bore" very well centered on the OD. Not feeling it to bore out a 48" "tube" to center the bore.

I purchased all steel dom tube.
 
I got .109” wall tube .030” over size for all my common bar stock. Is .109 thick stock heavy enough wall?

I purchased all steel dom tube.

If these quotes correspond? It is good you plan to use steel. But, I would want a heavier wall!
And less than .030" clearance. I know that sounds tight. But, I have pulled ALLOT of bar in my day. I always make simple collars for the tail end of the bar (no spindle liners).
Like you, I can fit a 36" bar "all in" the spindle. Any time I get sloppy with the OD of the collar? It shows up in the finish (and noise!). ​
I'm talking more than .010/.015" clearance to the draw-tube. No matter how good the jaws, or high the clamping pressure. Vibration is a powerful mo-fo!
Obviously, the issues lessen as the bar gets shorter. But, it can be a bitch to deal with sometimes.
Also, I never liked haas spindle liners, and they sure wore out fast! I don't know if they have changed them since I last used them? (around 2006)
Back then they were hard plastic with hollow voids between the inside and outside solid material.
We had one machine that ran a production job from 6061 about 50 hrs/week. We would only get about 2 months before the liner was sloppy enough to cause finish issues.
I don't think what you are planning (10"~12" extended) is necessarily dangerous. But, I think you may be setting yourself up for some PITA issues.
 
If these quotes correspond? It is good you plan to use steel. But, I would want a heavier wall!
And less than .030" clearance. I know that sounds tight. But, I have pulled ALLOT of bar in my day. I always make simple collars for the tail end of the bar (no spindle liners).
Like you, I can fit a 36" bar "all in" the spindle. Any time I get sloppy with the OD of the collar? It shows up in the finish (and noise!). ​
I'm talking more than .010/.015" clearance to the draw-tube. No matter how good the jaws, or high the clamping pressure. Vibration is a powerful mo-fo!
Obviously, the issues lessen as the bar gets shorter. But, it can be a bitch to deal with sometimes.
Also, I never liked haas spindle liners, and they sure wore out fast! I don't know if they have changed them since I last used them? (around 2006)
Back then they were hard plastic with hollow voids between the inside and outside solid material.
We had one machine that ran a production job from 6061 about 50 hrs/week. We would only get about 2 months before the liner was sloppy enough to cause finish issues.
I don't think what you are planning (10"~12" extended) is necessarily dangerous. But, I think you may be setting yourself up for some PITA issues.

Thank you so much for some of this information.

I was going to get .010” over tube with slightly thicker walls but jt burns website stated they make their liners .03”-.06” oversized so i figured I’d go with the small end of that.

I had a full set of liners for my old machine sqt18ms and it would take 4ft in the tube I sold all those liners with the machine but I remember them being very sloppy. Also wall were about .1” maybe a few were thicker. Liners were ancient but seemed factory made.

I may order up some more steel tube try to find around 1/4 wall and .01” over stock diameter. Especially for the smaller sizes. Pretty easy to get .12” wall tube in normal sizes.

Also been looking for a simple bar loader (don’t need a full feeder) currently I’m the simple bar loader.

I also thought about sending a cylinder hove through the tubes to smooth them.

Edit

I thought .01” may be too tight for some bar aswell and if things were not perfectly straight it wouldn’t work. That’s why I got the bigger material
 
Thank you so much for some of this information.

I was going to get .010” over tube with slightly thicker walls but jt burns website stated they make their liners .03”-.06” oversized so i figured I’d go with the small end of that.

I had a full set of liners for my old machine sqt18ms and it would take 4ft in the tube I sold all those liners with the machine but I remember them being very sloppy. Also wall were about .1” maybe a few were thicker. Liners were ancient but seemed factory made.

I may order up some more steel tube try to find around 1/4 wall and .01” over stock diameter. Especially for the smaller sizes. Pretty easy to get .12” wall tube in normal sizes.

Also been looking for a simple bar loader (don’t need a full feeder) currently I’m the simple bar loader.

I also thought about sending a cylinder hove through the tubes to smooth them.

Edit

I thought .01” may be too tight for some bar aswell and if things were not perfectly straight it wouldn’t work. That’s why I got the bigger material

After I made my post I thought about it a little more. And have to say, some of my experience may not apply to what you are trying to do.
I can imagine that .010" in a full-length liner would be pretty tight. My post is based on making a collar that is only 1" long and gets snugged up on the tail end of a bar with a set-screw.
That is probably 75% of my experience pulling bar. So, if a bar is not perfectly straight, it will still pull without too much drag. In a full length liner, that tight might be an issue?
Regardless, like I said, I don't think 10"~12" is dangerous. As long as your "stuff" is rigid, and fairly tight. I don't really think anything with a .109" wall is particularly rigid.
I actually think once the material is far enough along that your liner is empty it will be worse off than no extension at all.
The problem is: if it does start to whip? Once it starts, it will only get worse until either you stop it, or it goes ugly.
 
In my experience, .010" clearance is too tight. Slight bends in the material, oversized extruded aluminum, and slight bends in the liner will make feeding bars smoothly an issue. Industry standard seems to be about 1 mm clearance, so that's what I try to stick with.

I'm assuming the collar at the back of the spindle will have a flange and be drilled for screws to attach it to the spindle? You could make this piece longer so that it extends out the spindle. That would give the tube more support. Maybe extend the collar 5" so the tube only needs to extend out 5" from it to get the full 10"? A lot of my liners extend past the spindle around 5", so I wouldn't expect that to be a problem.

Will the extension be outside of the guards of the machine? I'd recommend making a cover to protect anyone from making contact with the spinning liner.

You might get coolant coming out the end of your liner and spraying everywhere. A coolant catcher extension might be needed. You can make or buy them.
 
In my experience, .010" clearance is too tight. Slight bends in the material, oversized extruded aluminum, and slight bends in the liner will make feeding bars smoothly an issue. Industry standard seems to be about 1 mm clearance, so that's what I try to stick with.

I'm assuming the collar at the back of the spindle will have a flange and be drilled for screws to attach it to the spindle? You could make this piece longer so that it extends out the spindle. That would give the tube more support. Maybe extend the collar 5" so the tube only needs to extend out 5" from it to get the full 10"? A lot of my liners extend past the spindle around 5", so I wouldn't expect that to be a problem.

Will the extension be outside of the guards of the machine? I'd recommend making a cover to protect anyone from making contact with the spinning liner.

You might get coolant coming out the end of your liner and spraying everywhere. A coolant catcher extension might be needed. You can make or buy them.

Some good pints here.

It will stick a few inches past the guarding on the machine. But there is other obstacles such that for someone to touch it they would have to run directly into a large red toolbox.

That’s a good idea on extending the flange I’ll check run out on it and see if it viable to extend or if it’s not flat I’ll consider how to make it flat.

I did plan on eventually making an extended coolant collector aswell for 2 reasons on being safety so nobody could touch the spinning liner and to keep the coolant mist away.

For a coming up job where I really need this I’ll be running pretty clean stainless bar stock. I’m thinking I’m going to put an oring groove in the very top of the liner where the bar rides to prevent an coolant from getting through into the liner. Although now that I think about it that will fail on the last bar segment.

Glad to know your liners extend 5” I could get away with that really.

People make think it way too unsafe but I think letting 1.25” bar stick out 5” is not a problem heck it will be sticking out almost that far on the spindle side.

I have run some sketchy thing on my old machine when I was a little more ignorant.

Another note I always set my max rpm to around 2500 the machine is capable of 6k.
For this job I may need to have that around 3500-4000 that’s were things get sketchy and I’m curious if this extension will be ok.
 
Did you check with the machine manufacturer. About 20 years ago we bought from Mazack a spindle extension that bolted on so we could use 4’ bars. I think the extension was about 10” long.

Bruce
 
Did you check with the machine manufacturer. About 20 years ago we bought from Mazack a spindle extension that bolted on so we could use 4’ bars. I think the extension was about 10” long.

Bruce

Did not check with Mazak but not sure I could afford it if I did. Got a quote on some boring bar holders for the lower turret and they were almost $2000 each
 
This is a Berns liner.............12" beyond the actuator............the tube is 2.25" IDx 2.50" OD. Bought this one new with a machine..............liner and a coolant catcher extender.............their extened liners are $$$$$ so I'm currently making my own from 5/8"Ø to 2"Ø by 1/8" increments. I'll buy some Trusty Cook liners in 2-3/8"Ø and 2-1/2"Ø to cover the whole range of stock sizes I run.................

IMG_0567.jpg



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This is a Berns liner.............12" beyond the actuator............the tube is 2.25" IDx 2.50" OD. Bought this one new with a machine..............liner and a coolant catcher extender.............their extened liners are $$$$$ so I'm currently making my own from 5/8"Ø to 2"Ø by 1/8" increments. I'll buy some Trusty Cook liners in 2-3/8"Ø and 2-1/2"Ø to cover the whole range of stock sizes I run.................

View attachment 321714



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I appreciate this.

Im considering purchasing a liner from them.
$400 for the liner $300 for the coolant collector.

They told me it would be fine with 4ft bars. But couldn’t give an rpm it would be safe at.
 
This is a Berns liner.............12" beyond the actuator............the tube is 2.25" IDx 2.50" OD. Bought this one new with a machine..............liner and a coolant catcher extender.............their extened liners are $$$$$ so I'm currently making my own from 5/8"Ø to 2"Ø by 1/8" increments. I'll buy some Trusty Cook liners in 2-3/8"Ø and 2-1/2"Ø to cover the whole range of stock sizes I run.................

View attachment 321714



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How is that liner held in the spindle? Does it just slide in and that's it?

For the smaller diameter liners you make, will they still have 12" extension? Assuming the OD of your smallest liner to be around 1", that seems like a lot hanging out.
 
I'd be VERY leery of taking a chance like that. I used to work for a major MTB and about once every few weeks, a bunch of pictures would make the rounds in the office of the latest spindle/barstock disaster. I saw some really mangled machines and some real eye opening invoices. Me? I'd keep the stock length to 36".
 








 
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