# Homemade live center



## Tozguy (Jan 8, 2020)

Have any of you folks made your own live center?
If so, would you mind sharing your design and experience making it?


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## Ken from ontario (Jan 8, 2020)

I believe Mikey made a  decent one a while ago. 
searched for it but couldn't find it. it could be my old brain playing tricks on me.


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## mikey (Jan 8, 2020)

Working on the write up. Hang on.


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## ttabbal (Jan 8, 2020)

mikey said:


> Working on the write up. Hang on.



It's been 13 minutes, according to the forum. You done yet?


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## DavidR8 (Jan 8, 2020)

14 minutes and counting... 


Sent from my iPhone using Tapatalk


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## martik777 (Jan 8, 2020)

For $12 why bother, I've had this for years, works great plus it can be used as a bullnose









						17.96US $ |ABSF 1Pcs Lathe Milling Center MT2 High Accuracy Live Revolving Center Medium Lathe Machine Tool Accessory for CNC Cutter|Lathe|   - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com


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## ddickey (Jan 8, 2020)

I was going to try and beat him too it but I can't find the write up.
I did but just for a project. I use it when tolerances are not needed. 
You need to grind it in with a toolpost grinder at a minimum while spinning the center.


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## middle.road (Jan 8, 2020)

1hr, 12mins....


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## mikey (Jan 8, 2020)

You see, there's this thing called Hawaiian Time - we done when we done! Seriously, it's all wrote down, I just need to polish it up a little more.


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## darkzero (Jan 9, 2020)

My GF is from Hawaii so I know this well. She also often says to me things like "take your time but hurry up!" & "you slow ride".  Hint hint  

Filipino time & Korean time is pretty much the same that I have learned from friends.


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## mmcmdl (Jan 9, 2020)

I have a few that I made years back , couple bearings mounted in a sleeve with the center lightly pressed in . I tapped 1/2"-20 threads in the back of them for different style shanks .


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## cathead (Jan 9, 2020)

I made a huge one a few years ago for machining on pipe.



View media item 94589


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## ddickey (Jan 9, 2020)

Ray C also has a very pro write up on the bull nose he made here a few years back.








						Bull Nose Live Center
					

I've been meaning to make this live center for a while now.  The bull-nose is a special size and length that would make a particular task a little easier.  Here's an outline image.  This is a background shop project that's going to take a while.  The nose is 4140 that I plan to bring up to the...




					www.hobby-machinist.com


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## mmcmdl (Jan 9, 2020)

Here's one of the many tiny one's with 1/2"-20 threads . Just made them up for different applications . You never know what engineers dream up , and you had to ready .


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## Tozguy (Jan 9, 2020)

martik777 said:


> For $12 why bother, I've had this for years, works great plus it can be used as a bullnose


Actually I already have a live center so I don't really need another. But it has always been a lot of fun for me to make things that I don't really need at three times the cost and almost as good as a bought one.


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## Tozguy (Jan 12, 2020)

I dreaded the thought of an MT2 taper slipping .............until now.

This is a live center made up from an MT3/MT2 sleeve, a homemade MT2 center, a 3/8ths ball bearing and a couple of screws
The set screw in the MT3 tang and a ball bearing act as a stop to prevent the MT2 taper from binding, but just barely. 

The screw in the end of the MT2 center is to provide a hard cupped socket for the ball bearing to ride in. 

The tang set screw has a 5/16 NF thread that allows for adjustment of the clearance in the MT2 taper. During preliminary trials I was able to get down to .0005'' clearance and still have the center rotate easily in the sleeve. The MT2 taper was lubed with Rotella 15w40 diesel oil.The MT2 center used for the trials is a low friction ball center but it spun very well so I can only think that the Rotella was a good choice.

These results are much better than those for the live center that came with my lathe which is much more bulky and has over .003'' of slop.

 I plan to make up another MT2 center with a 60deg point instead of a ball and provide for some means of lubrication on the run.


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## RJSakowski (Jan 12, 2020)

Here is one that I made some time ago for doing miniature work.  The bearings were salvaged from a computer hard drive.  It has a 1/4" straight shank for mounting in  a 1/4 Albrecht chuck.  The chuck is adjustable similar to the Set Tru chucks for centering.


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## mmcmdl (Jan 12, 2020)

Tozguy said:


> Actually I already have a live center so I don't really need another. But it has always been a lot of fun for me to make things that I don't really need at three times the cost and almost as good as a bought one.



That's why we're all here , isn't it ?


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## Tozguy (Jan 17, 2020)

Emergency live center.........

This is a trial that was just completed with success.
Using a Weldon end mill holder and a broken four flute end mill it was fairly easy to rig an internal stop and allow the end mill to spin in the holder.
With the set screw removed from the holder and the holder installed with the hole facing up, some 0w20 synthetic engine oil was added in the hole.

Hopefully the photos are self explanatory. There is absolutely no precision required in making up the other parts. Clearances between the end mill and holder are minimal as is and once the oil fills the void there is no play. My 3/8 shank end mill was broken off near the root. The shoulder at the root is perfect at 60 deg.


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## Tozguy (Jan 18, 2020)

Used the end mill live center again today. The job was to slim down the shoulder on an MT2 center.
This was the set up.



The tip of the MT2 center was driven by friction from a 1/2 steel rod held in a collet and a relatively deep center divot drilled in it.
To ensure that enough friction was available the tailstock hand wheel was preloaded with a weighted lever. This kept some pressure on both centres.


At 330 rpm and a .005'' depth of cut it produced nice long curly chips with a bit of smoking from the cutting fluid. The resultant finish is very acceptable even though feed was manual.



The live center performed flawlessly. After the hole in the end mill holder was filled with oil a plastic sleeve was installed to keep chips out of it.
The center has very low drag and can take significant thrust. After around 20 minutes of turning there was still oil in the hole and there was no heat build up. It seems like this live center could be used all day with no problems.

Another significant discovery was that it is possible to drive work between centres without using a dog. In this case the contact surfaces at the headstock end were completely clean and dry, with a means of providing some constant pressure on the center.

Just wanted to share this with you. I am so tickled by how this live center works that I rate it totally awesome.


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## brino (Jan 18, 2020)

Very interesting.......



Tozguy said:


> There is absolutely no precision required in making up the other parts.



I guess the one place you need to get things close is the total length out the back to retain the ability to eject from the tailstock.

Thanks for sharing this!
-brino


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## Tozguy (Jan 19, 2020)

Hi Brino,
The end mill holder originally ejected well at a point within the last inch of quill travel.
Therefor I planned on adding as little as possible on the end of the holder to keep the new ejection point close to the original point.

Once the extension of the end mill in the holder is decided and the other parts measured, it is a simple matter to calculate how long the spacer rod has to be. There is also the possibility of using the set screw and jam nut somewhat for minor adjustments.

Because the end mill center is free floating I was concerned about it falling out accidentally during handling. It turns out that once the holder is filled with oil, suction will keep the end mill from falling out.

It was also interesting to note that there was no oil loss from around the end mill. I did not have to add oil at all after 20 mins of run time. This would indicate how good the parts fit.

MT3 end mill holders are currently on sale at Busy Bee Tools for 25 CAD. Broken end mills should not be too hard to come by but even a new one is only around 10$. Considering how straightforward and fun it is to make up one of these live centres there is no reason for a hobbyist to be without one for that price.

My plan now is to buy a new 1/2 - 1/2 four flute end mill and grind the end to a 60 deg point. Then dedicate my MT3 1/2 holder as a live center. With the longer end mill it should be possible to run it at the right depth in the holder.


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## SLK001 (Feb 7, 2020)

martik777 said:


> For $12 why bother, I've had this for years, works great plus it can be used as a bullnose
> 
> 
> 
> ...



I picked up one of these.  The only problem is that the taper end is too short to be knocked out by the tail stock.  I will probably have to build up the end with my MIG and then grind it down to a nice profile.


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## Tozguy (Jun 6, 2020)

ddickey said:


> I was going to try and beat him too it but I can't find the write up.
> I did but just for a project. I use it when tolerances are not needed.
> You need to grind it in with a toolpost grinder at a minimum while spinning the center.


Would you elaborate on how you set things up to grind the point while spinning the center please?
I am all ears for anyone else who has a way to do this.


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## ddickey (Jun 6, 2020)

You have to grind the point in the bearings.
If I recall I put the center in the TS and spun the tip with a cordless drill using a strong rubber band while using the tool post grinder to grind the tip. I needed someone to help hold the drill but got it done. The result was not acceptable imo with .0004" TIR.

By the way what happened to Mikey's write up? Hawaiian time can't be this slow.


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## Tozguy (Jun 6, 2020)

Thanks for the explanation.
 I think mikey's article was moved to its own thread. This is the link: https://www.hobby-machinist.com/thr...ter-for-the-sherline-lathe.81755/#post-709283


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## Tozguy (Jun 6, 2020)

mikey said:


> Here is something that is not in that article and as I mentioned earlier, it was learned from a mistake. I said that the tips must be shaped by using the housing as a mandrel, right? The reason I know that is because I made a shaping mandrel and I was really careful when I made it but those tips had so much run out that you could use it to stir coffee under power! I was trying not to risk marring the housing but eventually found that it was the only way to assure concentricity. Lesson learned.



Say mikey, is it OK if I ask you in this thread for more detail on the set up you recommend for cutting/grinding the point?


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## mikey (Jun 6, 2020)

Tozguy said:


> Say mikey, is it OK if I ask you in this thread for more detail on the set up you recommend for cutting/grinding the point?



Sure, what do you want to know?


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## Tozguy (Jun 6, 2020)

What did you use to hold the housing, an independant 4 jaw or other means? Was the housing held stationary while the center was spun? How did you spin the center and at what speed? Did you use a single point cutter or a tool post grinder? 
Sorry if its in your write up but I missed it.


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## mikey (Jun 6, 2020)

Tozguy said:


> What did you use to hold the housing, an independant 4 jaw or other means? Was the housing held stationary while the center was spun? How did you spin the center and at what speed? Did you use a single point cutter or a tool post grinder?
> Sorry if its in your write up but I missed it.



I had the advantage of the bearing housing being separate from the bearing and arbor so it was easy to hold in a 4 jaw chuck. In order for the tips to be accurate, they MUST be mounted in the housing in which they will be used. Even Royal has to do it this way, although they grind the tips instead of cut them. So yes, hold the bearing housing in a 4 jaw and get it dialed in to ZERO, not close to zero. I used aluminum flashing to protect the finish from the jaws. 

Once the housing is dialed in and locked in the 4 jaw, the tips were mounted into the housing. My tips are threaded so they just screw into the housing. The tips are made from O-1 steel. I used a compound slide set at 30 degrees to cut the taper on the tips on the backside of the part. I used a brazed carbide cutter mounted upside down to rough them out, then I switched to a very sharp HSS tool to put a nice finish on them. O-1 likes to rough slow and finish fast. By slow, I think I went with 60 sfm to rough and as fast as my lathe could go and with a slow feed when taking light finishing cuts.

Hope this helps. If this is not clear, let me know.


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## Tozguy (Jun 6, 2020)

Yes it helps, thank you. I have no idea what the maximum speed of your lathe is so if you could give me a ballpark figure that would be great.
I don't imagine that you will have to touch up the points very often since they are heat treated. But if you ever need to touch up the points from normal wear and tear or a mishap, how would you go about it?


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## mikey (Jun 6, 2020)

My Sherline tops out at 2800 rpm.

If I need to touch up the tips, I will zero the housing in the 4 jaw with the tip in place and put a diamond flat file in a tool holder and file them accurately with the compound.


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## Tozguy (Jun 7, 2020)

Thanks mikey.

The reason I ask about speeds is that I have modified the live center supplied with my lathe. The project is now at the stage of the final trueing cut on the point.

My approach for this has been to hold the MT3 taper in the lathe spindle. With the lathe spindle stationary there is a drive shaft that runs through the lathe spindle bore to drive the live center. The drill driving the center spindle has a maximum no load speed of 1350 rpm. Initial cuts have shown that the speed does not drop much when the cutting starts.

Using a very sharp HSS-Co insert and just a hint of DOC the chips amount to the finest dust I have ever produced. The first pass just hit the high spots and the second pass produced a consistently fine dust for the full length of the pass. The finish is not as shiny as I hoped but things look promising anyway.

The steel is rather tough. It is a piece of shaft from an unknown source. It seems to slip relatively easy in the 4 jaw even with the jaws are good n tight. This slipping does not marr the shaft so my impression is that it might not be the easiest steel to cut (with my equipment). Nonetheless I expect to have to touch up the point from time to time so it seems appropriate to fine tune the procedure.

There are other tools I could use to drive the center spindle. One has a variable speed control for up to 30 000 rpm. I would make that work if I thought it might be worth the effort. Making speed trials would help answer the question but I am not keen on shortening the point more than necessary.

So any guidance available from the folks here on how to improve the finish would be welcome.

For now I am focused on the final cut. Buffing/polishing could ultimately give it a mirror finish but I would like to perfect the cut first.


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## mikey (Jun 7, 2020)

I cannot see the tip of your cutting tool. Can you show me a pic?

One option might be to grind a shear tool. I haven't used them but they are said to take light cuts to produce fine finishes.


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## Tozguy (Jun 7, 2020)

Interesting......
I could not take any decent photos with my old camera so I decided to try my new Teslong borescope that has magnification. And I see things now that my old bare eyes did not pick up before.


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## mikey (Jun 7, 2020)

Mike, your tool would probably work better if you try two things:

Add some positive side and back rake. Currently, the tool looks to have zero rake, I think. Sorry about the crooked lines but if you regrind the tool to include side and back rake the tool will cut much cleaner.




Try cutting with the end cutting edge. That is, use the end edge just slightly back from the nose radius. Taking light finishing cuts with this edge will give a nice finish. Currently, you are cutting with the nose radius, which is why all those lines are showing up. You want to shave/shear the surface and using the end edge will do that for you.


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## Tozguy (Jun 9, 2020)

Your post made me think of using my tangential holder.


So I gave that a try. I set the tool as  you mentioned and got a much better finish.
The chips looked like ultra fine steel wool.




Thanks for your help mikey.

BTW the finish is better than it looks, it is very smooth to the touch.
It seems as good as can be expected with me at the hand wheel, probably feeding too quickly.


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## Downunder Bob (Jun 9, 2020)

Hawaii time sounds a bit like "territory time." with reference to the Northern Territory of Australia with Darwin as its capitol city. My late father who was based in Adelaide South Australia, had many business arrangements in the territory.

He often related a story of one such business meeting. While seated in a client's office in Darwin, the client took a phone call, hanging up, he said to my father "Excuse me, I won't be long" and left his office.

After some time contemplating his finger nails, my father got up, and went out of the office to ask the client's secretary where he was, and when will he be back. The secretary quite non plussed replied that he'd just gone down to Alice (Alice Springs) (About 1000m south) he'll be back in a couple of days.

Dad thought that it explained Territory time quite well.


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## mikey (Jun 9, 2020)

Tozguy said:


> BTW the finish is better than it looks, it is very smooth to the touch.
> It seems as good as can be expected with me at the hand wheel, probably feeding too quickly.



Isn't it interesting what happens when we use the edges on our turning tools? The finish looks good; your camera is just picking up highlights. Glad you got her done!


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## savarin (Jun 9, 2020)

We have a Swiss friend who always asks "Is that Swiss time or  Filipino  time" when we tell her we will be there at.....


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