So I got this cheap live center on eBay, and have some questions

[ChazzC]

I have the MT2 version of (what I believe is) Wobbly's live center - $24 all-in on eBay 2 years ago but the listing is no longer assessable, but it's like this one:



can confirm once Wobbly has a chance to upload photo. Mine was fine, no roughness or discernible issues. I also have one of these sets (eBay, from India, around $60 IIRC):


The box was a little wonky, but I got a partial refund and fixed it; nothing wrong with the tooling.

I got this MT2 bullnose (1/2" – 2-1/2") live center early this year primarily to use for rough alignment of existing large holes on the mill (using an R8/MT2 adapter), but chose the MT2 so I could also use it on the lathe. Also good quality with no roughness:



I don't expect these live centers to perform as well as name brand tools, but I do expect them to be as described and be fit for purpose (meaning that I shouldn't have to fix manufacturing issues. I have the same expectations for any tools/tooling that I purchase, regardless of the source. I have returned problem tools/tooling purchased on eBay, Amazon, Zoro and McMaster-Carr, with either replacements or refunds (and in some cases, refunds plus replacements). I got no push-back on these returns, and continue to buy from them.

 

[RaisedByWolves]

I also have one of these sets (eBay, from India, around $60 IIRC):

View attachment 503875
The box was a little wonky, but I got a partial refund and fixed it; nothing wrong with the tooling.

Link?

 

[WobblyHand]

Here's my live center, blued.
The taper angle is roughly correct. Might be 40-50% contact, which is kinda ok for the price range. My tail stock taper is still a little messed up, even after running a MT3 reamer through it a while back. I feel some stuff sticking sticking out with my finger. Think it marred the new taper, kind of soft? Anyways, what do your experienced eyes tell you?

Hard for me to tell sometimes on this non drying blue.

 

[ChazzC]

Link?

Unfortunately, this is the only listing that is still active:

1 NEW BULL NOSE LIVE LATHE CENTER. MT2. #2 MORSE TAPER. 2.5" HEAD (W316) | eBay

1 NEW BULL NOSE LIVE LATHE CENTER. HEAVY DUTY. #2 MORSE TAPER. We describe our tooling as it is, we do not hide anything. OVERALL LENGTH FROM ONE END TO THE OTHER IS ABOUT 5-1/2".

www.ebay.com

The extended nose is similar to this one ($4 less than I paid 2-1/2 years ago):

MT2 Live Center Morse Taper Precision 0.000197'' CNC Long Spindle Lathe Tool 2MT | eBay

For high speed lathe and CNC lathe. Shank Size: Morse taper #2. Triple ball bearing design with extended long spindle with CNC point to enhance grinding wheel clearance. Center Point: 60 degree. 1 x Live Center.

www.ebay.com

And the multi-tip kit is like this one:

MT2 Multi Purpose Live Center Set with 7 Interchangeable Multi Points New Boxed | eBay

Made of hardened & ground steel. Supplied in a Quality Wooden Box.

www.ebay.com

 

[Jake M]

Yes, I should know better.

Me too, but let me tell you about my dirt cheap live center...

All gritty when it turned, four times the advertised accuracy, heap o' crap.....

First, I came to grips with the error (eccentricity) versus the TIR. Fair enough, mine showed two tenths TIR as well, but it was advertised as only one tenth TIR. But in my world, that's plenty close enough. Hard to swallow at first (tolerances and all...), but in all cold, hard, factual piece of crap seller junk offshore crap shoot.... It's pretty good for a cheapie. I kept it.

Two tenths TIR on mine, versus 4 on yours? It's a live center and a cheap one at that. If you're gonna work to anything that requires 4 decimal places, a live center isn't the way to do it. Dead centers do that, live ones don't. (in the hobby realm anyhow, I'm sure there's some ten thousand dollar CNC robot attachment that could do it...) So long as you're still in the "ball bearing" class of live centers, they just don't do that.
And yet, if we don't pay attention to how much floppier they are than a dead center..... They turn out good parts and and you don't even notice how floppy they are, because at that level, you're watching and adjusting over the whole length of the part anyhow.....

As for the "grittyness"...
How long is the return window? If it's not "now"..., here's what I did with mine. I stuck a piece of half inch EMT tubing in the lathe chuck (pipe cutter cut, zero precision), I ran the dead center up into the end of it, turned it at something like (probably, it was a long time ago), but probably 6 or 800 RPMs, and just let it run for (probably) a half an hour or so while I worked on providing proper power to my new at the time lathe. I remember being scared to death of the "two headed snake" extension cord that I used for temporary 240 volt power, running back and forth across the basement, Conduit clip in the concrete, go see if the lathe is gonna burn my house down, go do another conduit clip, go see if the house is on fire yet, go install another clip, check the whole house because there must be a fire somewhere by now... Anyhow, by the time I chickened out, it ran smooth. My intention (and my recommendation to you) is to do that ( or similar), right off the bat. Wear it in or wear it out, BEFORE the return window closes.

Honestly, I couldn't tell you what the initial TIR was, I never measured that until AFTER I'd run the bearings in to see if they'd shut up, which they did... It "might" even straighten out a little if the bearings are running "smoother".

Just asking for an opinion on what this means.

The actual error statement, actual vsrsus TIR, it is what it says on the tin. What does that error mean in your shop? Probably nothing. 4 tenths (two tenth of eccentricity), divide that over a part that needs tail stock support, and you probably wont' find it. But you won't get that close anyhow, because the part will more than likely deflect enough to make it a moot point, and a live center's going to have some deflection as well. You'll naturally and inherently be looking for that anyway. Or, use that "wobbly) live center on a part that's short enough to not need tailstock support, but you do it anyhow? It'll probably deflect the center or the whole tailstock enough to bury most of that eccentricity anyhow.

So yeah... Give it a hot supper, see if it survives, and go from there.

 

[WobblyHand]

Me too, but let me tell you about my dirt cheap live center...

All gritty when it turned, four times the advertised accuracy, heap o' crap.....

First, I came to grips with the error (eccentricity) versus the TIR. Fair enough, mine showed two tenths TIR as well, but it was advertised as only one tenth TIR. But in my world, that's plenty close enough. Hard to swallow at first (tolerances and all...), but in all cold, hard, factual piece of crap seller junk offshore crap shoot.... It's pretty good for a cheapie. I kept it.

Two tenths TIR on mine, versus 4 on yours? It's a live center and a cheap one at that. If you're gonna work to anything that requires 4 decimal places, a live center isn't the way to do it. Dead centers do that, live ones don't. (in the hobby realm anyhow, I'm sure there's some ten thousand dollar CNC robot attachment that could do it...) So long as you're still in the "ball bearing" class of live centers, they just don't do that.
And yet, if we don't pay attention to how much floppier they are than a dead center..... They turn out good parts and and you don't even notice how floppy they are, because at that level, you're watching and adjusting over the whole length of the part anyhow.....

As for the "grittyness"...
How long is the return window? If it's not "now"..., here's what I did with mine. I stuck a piece of half inch EMT tubing in the lathe chuck (pipe cutter cut, zero precision), I ran the dead center up into the end of it, turned it at something like (probably, it was a long time ago), but probably 6 or 800 RPMs, and just let it run for (probably) a half an hour or so while I worked on providing proper power to my new at the time lathe. I remember being scared to death of the "two headed snake" extension cord that I used for temporary 240 volt power, running back and forth across the basement, Conduit clip in the concrete, go see if the lathe is gonna burn my house down, go do another conduit clip, go see if the house is on fire yet, go install another clip, check the whole house because there must be a fire somewhere by now... Anyhow, by the time I chickened out, it ran smooth. My intention (and my recommendation to you) is to do that ( or similar), right off the bat. Wear it in or wear it out, BEFORE the return window closes.

Honestly, I couldn't tell you what the initial TIR was, I never measured that until AFTER I'd run the bearings in to see if they'd shut up, which they did... It "might" even straighten out a little if the bearings are running "smoother".



The actual error statement, actual vsrsus TIR, it is what it says on the tin. What does that error mean in your shop? Probably nothing. 4 tenths (two tenth of eccentricity), divide that over a part that needs tail stock support, and you probably wont' find it. But you won't get that close anyhow, because the part will more than likely deflect enough to make it a moot point, and a live center's going to have some deflection as well. You'll naturally and inherently be looking for that anyway. Or, use that "wobbly) live center on a part that's short enough to not need tailstock support, but you do it anyhow? It'll probably deflect the center or the whole tailstock enough to bury most of that eccentricity anyhow.

So yeah... Give it a hot supper, see if it survives, and go from there.

I can try something like that. The point is probably so soft, that I'd better center drill a cone for it, and let it run a while. If the bearings self destruct, I'll say defective bearings - since they shouldn't have worn out - this is considered normal use for the part.

Return window ends October 23.

 

[WobblyHand]

The Royal's and Riten's look mighty fine, but alas they are far too expensive for me to justify for my blundering hobby use.

 

[RaisedByWolves]

Me too, but let me tell you about my dirt cheap live center...

All gritty when it turned, four times the advertised accuracy, heap o' crap.....

First, I came to grips with the error (eccentricity) versus the TIR. Fair enough, mine showed two tenths TIR as well, but it was advertised as only one tenth TIR. But in my world, that's plenty close enough. Hard to swallow at first (tolerances and all...), but in all cold, hard, factual piece of crap seller junk offshore crap shoot.... It's pretty good for a cheapie. I kept it.

Two tenths TIR on mine, versus 4 on yours? It's a live center and a cheap one at that. If you're gonna work to anything that requires 4 decimal places, a live center isn't the way to do it. Dead centers do that, live ones don't. (in the hobby realm anyhow, I'm sure there's some ten thousand dollar CNC robot attachment that could do it...) So long as you're still in the "ball bearing" class of live centers, they just don't do that.
And yet, if we don't pay attention to how much floppier they are than a dead center..... They turn out good parts and and you don't even notice how floppy they are, because at that level, you're watching and adjusting over the whole length of the part anyhow.....

As for the "grittyness"...
How long is the return window? If it's not "now"..., here's what I did with mine. I stuck a piece of half inch EMT tubing in the lathe chuck (pipe cutter cut, zero precision), I ran the dead center up into the end of it, turned it at something like (probably, it was a long time ago), but probably 6 or 800 RPMs, and just let it run for (probably) a half an hour or so while I worked on providing proper power to my new at the time lathe. I remember being scared to death of the "two headed snake" extension cord that I used for temporary 240 volt power, running back and forth across the basement, Conduit clip in the concrete, go see if the lathe is gonna burn my house down, go do another conduit clip, go see if the house is on fire yet, go install another clip, check the whole house because there must be a fire somewhere by now... Anyhow, by the time I chickened out, it ran smooth. My intention (and my recommendation to you) is to do that ( or similar), right off the bat. Wear it in or wear it out, BEFORE the return window closes.

Honestly, I couldn't tell you what the initial TIR was, I never measured that until AFTER I'd run the bearings in to see if they'd shut up, which they did... It "might" even straighten out a little if the bearings are running "smoother".



The actual error statement, actual vsrsus TIR, it is what it says on the tin. What does that error mean in your shop? Probably nothing. 4 tenths (two tenth of eccentricity), divide that over a part that needs tail stock support, and you probably wont' find it. But you won't get that close anyhow, because the part will more than likely deflect enough to make it a moot point, and a live center's going to have some deflection as well. You'll naturally and inherently be looking for that anyway. Or, use that "wobbly) live center on a part that's short enough to not need tailstock support, but you do it anyhow? It'll probably deflect the center or the whole tailstock enough to bury most of that eccentricity anyhow.

So yeah... Give it a hot supper, see if it survives, and go from there.

It is possible to grind your toolbit so it minimizes deflection, and makes the main force of the cutting action want to lift the part rather than push it to the rear which lessens the amount of deviation in size over the length of the part .

Both positive take and your chip breaker can play a part in this.

 

[tobnpr]

Two tenths TIR on mine, versus 4 on yours? It's a live center and a cheap one at that. If you're gonna work to anything that requires 4 decimal places, a live center isn't the way to do it. Dead centers do that, live ones don't. (in the hobby realm anyhow, I'm sure there's some ten thousand dollar CNC robot attachment that could do it...) So long as you're still in the "ball bearing" class of live centers, they just don't do that.
And yet, if we don't pay attention to how much floppier they are than a dead center..... They turn out good parts and and you don't even notice how floppy they are, because at that level, you're watching and adjusting over the whole length of the part anyhow.....

My take as well. I just don't use a live center when I need near zero runout- which isn't often enough to justify the hundreds of dollars for one.
I use a dead center, plenty of STP lube on the part/center and turn at as slow an rpm as I can to get the results needed.

 

[G-ManBart]

The Royal's and Riten's look mighty fine, but alas they are far too expensive for me to justify for my blundering hobby use.

I've bought two extended nose live centers in the past year or two. I started with an inexpensive one for my Logan that used 3MT and it was smooth as can be, no issues:

3MT MT3 Bearing Long Nose Turning Revolving Live Center Accuracy 0.000197'' | eBay

1x MT3 Live Center. Airless Paint Spray Accessory. Airless Paint Spray. Auto Door Lock. Triple ball bearing design with extended long spindle with CNC point to enhance grinding wheel clearance. Switch Parts & Accessory.

www.ebay.com

I recently bought a Victor with a 4MT tailstock and needed an extended nose center for it as well. I realized how much I was using the extended nose center on the other machine so I went one step nicer and bought a Z Live Center for the Victor. They get really good reviews as being one of the better import centers and the one I got is smooth as can be as well. This is the 3MT version of what I bought. Come to think of it, I haven't put an indicator on it, but I did use it when I centered the tailstock and the results have been good, so I'm not overly worried....guess I'll have to check it just out of curiosity. The other live center I have for that lathe is a Rohm which is really nice, but a much fatter profile.

NEW 3MT 0.000197" CNC PRECISION LONG SPINDLE LATHE LIVE CENTER MORSE TAPER #3 | eBay

Designed for high speed lathe and CNC lathe to achieve high precision. Shank Size: Morse taper #3. We are carrying over 200 different types of high quality lathe live centers and dead centers. All of our products are 100% inspected.

www.ebay.com