Turning between centers - another way

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Texatdurango

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There has been a fair amount of discussion of turning between centers and questions always pop up and it seems like we've never really sat down and discussed the process from start to finish. Many folks are still confused as to what exactly is required to turn "center to center".

So, I took the time to photograph some steps today as I turned a pen and hopefully the following photo guide will help some to better understand what is involved and how simple this method of turning pen blanks really is.

As with anything else, this is not THE WAY of doing this, it's just ANOTHER WAY.... my way!:smile: Take from it what you will, modify as you see fit and hopefully this will be of some benefit. If you see something I left out or something you think will work better, by all means speak up and I'll add it in. This is designed as a guide to turning center to center not just showing my personal methods.

Step1. To turn between centers will take a few tools you may not have, namely a 60 degree "dead center" (lower right) and a 60 degree "live center" (also lower right). Other tools that you may find handy are the Beall collet chuck and a Sorby "steb center (both shown lower left). Here are most of the tools I will be using for this demo.



Step 2. First, mark a center on each side of your blank. This little tool is called a "Pen Pal" and I have no idea where I bought it but it is SO handy! The round thing you see is a magnet I glued to it because it hangs on the side of my shop fridge.



Step 3. I use an automatic center punch to mark a dimple in the blank for the centers to zero in on.



Step 4. Mount the square blank between the steb center (left) and a live center (right). Here I use a 6" tool rest.



Step 5. Through the magic of the internet, the blank is now round. That was SO easy! I turn all my blanks to just under .750" so they fit nice and snug in the 3/4" collet and don't allow for any wobble.



Step 6. A benefit of rounding the blank before drilling is that I can see exactly what the pen will look like as I decide how to position the tubes before cutting. Here I decided I want the darker pattern on the cap.



Step 7. Again, the blanks mysteriously cut themselves on the band saw and one of them hopped into the Beall collet chuck for drilling. I find this method of drilling to be very accurate and alllows me to drill larger holes in narrower blanks than I would on the drill press. The bit shown is a 37/64" but I drill 39/64" holes into 3/4" blanks with no worry. To aid in accuracy I always start the hole with a center drill which is shown in photo one just under and to the left of the twist drill bits. These specialized short bits allow for no wobble or flexing when finding the dead center of a blank. It's nice to see a hole dead center at the entry side AND be dead center at the opposite end.



Step 8. After drilling I square up the ends with a little sanding tool I made. I make little delrin bushings for every pen kit I make. The little bushings keep the blank centered on the sander post.



Step 9. Now we have a squared up blank ready to mount on the lathe and turn to size. Oops, I need to remove my little bushing first!



Step 10. Here we have a top and bottom blank with their bushings inserted, ready to turn. Note the red markings on the blanks, these make sure I keep the top and bottom oriented. It's hard to see in the first photo but these centers have 60 degree holes in the ends which allow the 60 degree centers to center up the blanks when turning. These special bushings are available from several forum members but I just take a 60 degree center drill and drill out the bushings I buy from my kit vendors or make my own on my metal lathe.



Step 11. Here we go turning a blank mounted between a dead and live 60 degree center. The blank is snugged up with the tailstock and not much pressure is required to hold the blank and to keep it from slipping. You may recognize the tool I am using, it is my favorite for turning down a blank but use whatever you are comfortable with. Also note the short tool rest, which I think is a key tool in turning between centers since it allows you to get up close to your work without fowling on the centers. Rick Herrel (rherrell) on the forum makes these neat little tool rests.



Step 12. Here we are with the blanks turned down just proud of the bushings. The blank now comes off and we say adios the the bushings.



Step 13. With the blank mounted back on the lathe between the two centers, I sand the blank down to size. Please note that sanding this way keeps any metal dust from contaminating the blank since the sand paper doesn't even touch any metal. I like Abranet and will sand the blank starting with 400 then 600 before removing. Note: I apply only enough pressure to make sure the live center rotates freely as it doesn't take much to hold the blank between the centers. DO NOT over tighten the tailstock else you might stretch the brass so it doesn't fit properly over mating kit parts.



Step 14. Since kit parts can vary from kit to kit and rather than rely on bushings, I measure the mating kit parts then check the blank to make sure it is where I want it to be. When doing a CA finish I will sand the blank slightly undersize then build up the blank with CA.



Step 15. When I'm satisfied with the diameter, I clean the blank with alcohol and do a quick wipe with Mylands Sanding sealer which REALLY brings out the colors of the wood. Again, notice that the towel comes no where near the metal centers.



Step 16. Now for the CA and thanks to Don Ward aka it's virgil, they are Bounty towels! :biggrin: Again... Look ma, no bushings! No bushings for the CA to stick to, neither metal nor delrin! The delrin bushings fall into the 'to each their own" category, personally I don't see the need since they just add a bit of hassle with the CA trying to stick to them and I want this to be as hassle free as possible.



Step 17. Here we go, a few good coats of CA and ready to sand. At this point I have learned to sit the blanks aside and cure for at least a day before sanding. I got to thinking once that if CA outgasses enough to fog over plating on a kit a day or two after assembly, then the CA is still curing. I have a theory that sanding freshly set CA causes deeper scratch marks in the soft CA than letting it sit and get harder. So it is my belief that letting the blank sit a day before sanding makes the blank harder and doesn't get scratched as easily so you get a better finish with less deep scratches to remove.



Step 18. In my opinion, applying CA without bushings also allows CA to roll over the edge, and soaking up into the blank thus sealing the ends of the blank as well. This MIGHT help in the long run by keeping moisture out of the blank during actual use but has not been clinically proven! :biggrin:



Step 19. So, here we go, two blanks turned, sanded and a snappy finish applied all between two centers.



Step 20. Before sanding the CA, here is a little step I like to do and it REALLY smoothes the blanks out allowing me to start sanding with 600 grit rather than coarser grit paper. Running a skew across the CA turns away many of the ridges left from applying the CA and allows one to start with finer grits thus doing away with the deeper coarser scratches left by the coarser grits. This only works if you build up the CA a bit over the finished diameter then trim and sand it down to the final diameter. I find that this gives a killer DEEP looking finish to the pen. After skewing the blank I'll do away with 400 or 500 grit and start with dry 600, 800, 1000 Abranet, plastic polish (to check for minor scratches) then off to the buffer.



Step 21. Now and then I get carried away with my paper towels and get a little CA on the centers. I insert a 7mm bushing between them and using a knife, clean the glue off. The bushing between them also rotates the live center for cleaning.



Step 22. A little 400 grit abranet and the centers are shiny as new even if the lousy photo doesn't show it!



Step 23. Here is the result of my efforts, another nice pen and I didn't even have to stop and try to remember where on earth my mandrels are hidden these days! :biggrin:



Hope you enjoyed reading but more importantly I hope this will provide some answers for someone.
 
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rjwolfe3

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Wow! George, that is one of the best tutorials I have ever read. I enjoyed every bit and even learned what I have been doing wrong. Thank you so much!
 

Rangertrek

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Very Nice

You did a great job with the step-by-step instructions on "your' method of turning between centers. The photos are a great help with understanding the method. I have been trying something very similar to this on my last few pens, based on some of (I think) your prior posts on this subject. I am gradually moving away from the mandrels.

I will need to give that last skew technique a try. It will seam hard for me to go back on a finished blank with a tool.
Thanks again for the demonstration. :smile::smile: Well done!!
 

Rmartin

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That's an excellent post, but I have 1 very very important question!


You have a fridge in your shop?

That is too cool!​

Seriously, I ended up with a groove in my live center while turning between center. Is this due to a poor quality live center, or am I tighting too much?​
 

jleiwig

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If you remember where you got that penpal I'd sure love to know!

Great job George. I do mine almost exactly the same way, although I'm partial to Viva myself!
 

PTownSubbie

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George,

Are those normal bushings that you would use on a mandrel or the special between center bushings?

Great instructions BTW! Thanks a ton. I have tried a few of these things before but have been afraid of too much pressure on the blank causing the tube ends to flare.
 

Texatdurango

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That's an excellent post, but I have 1 very very important question!


You have a fridge in your shop?

That is too cool!​


Seriously, I ended up with a groove in my live center while turning between center. Is this due to a poor quality live center, or am I tighting too much?​
Well yes But... it's a small one, just large enough to hold the microwave and toaster oven! Any larger and I couldn't sit my tea water dispenser next to it. When I go out to the shop for the day... I don't have to go back in the house for much ! :smile:

A groove in your live center! You mean where the brass tube actually cut a groove in the 60 degree point? If that's the case I would say you're live center is dead. I had one last year that had a bad bearing and there was no way to lubricate or change it so I just tossed it. You have to have it snug enough to at least put tension on the center and make it spin but I have mine loose enough that a heavy hand during sanding would stop the blank.
 

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Texatdurango

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George,

Are those normal bushings that you would use on a mandrel or the special between center bushings?

Great instructions BTW! Thanks a ton. I have tried a few of these things before but have been afraid of too much pressure on the blank causing the tube ends to flare.
I have a hodgepodge of bushings, most of which are the $3 variety that you buy from Craft Supply, Beartooth, etc. I just mount them in a collet chuck and drill them with a 60 degree center drill bit.

I stopped ordering bushings with the newer kits I try and just make my own from steel or aluminum rod.

As far as pressure on the blanks, that's a good point, I think I'll add a note on the tutorial. I only apply enough pressure to keep the live center spinning. When I first started turning this way I was always checking the tubes to see if I was spreading them but never noticed any problems.

Everyone just remember... don't crank the tailstock down!
 
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Great tutorial George. Basically the way I turn blanks and I also have been using factory kit bushings center drilled. I've got some of Johnnycnc's bushings coming that I can't wait to test drive
I use the small bags that kit parts come in over the centers (held with small elastics) when sealing and finishing to keep the centers cleaner. Less cleanup, just slip off the bags and throw them out.
 
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For those of you turning between centers, I wonder if you find it an issue when doing slims or similar pens with two halves. Since I'm new, when I'm turning the slims, I like to see the top and bottom halves together so I can make sure their contours match each other. Is this not and issue for most of you?

Mike
 

Rmartin

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A groove in your live center! You mean where the brass tube actually cut a groove in the 60 degree point? If that's the case I would say you're live center is dead. I had one last year that had a bad bearing and there was no way to lubricate or change it so I just tossed it. You have to have it snug enough to at least put tension on the center and make it spin but I have mine loose enough that a heavy hand during sanding would stop the blank.
I think the groove was caused by the bushing. I didn't even notice it until turning between centers one day and started getting a vibration, which I knew couldn't be. But it was. I am still able to use the center with a mandrel with no vibration. I have since replaced that center, but I'm kinda afraid to ruin another turning between centers.
 

tgraytn

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George,

This is FANTASTIC and much appreciated! Thanks again for taking all of the time to photo each step and follow that with the instructions.
 

mick

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George, FANTASTIC tutorial! Anyone thats reads this thread should have no questions about turning between centers or TBC. :biggrin: Our methods are basically alike EXCEPT I don't round my blanks before drilling as I use a 4 jaw chuck to hold them. HOWEVER after reading that one of the reasons you round them is to see what they will look like ....I may be converted. Too many times I've got a pen roughed out and wished I'd have cut it or oriented it differently.
 

Texatdurango

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George, FANTASTIC tutorial! Anyone thats reads this thread should have no questions about turning between centers or TBC. :biggrin: Our methods are basically alike EXCEPT I don't round my blanks before drilling as I use a 4 jaw chuck to hold them. HOWEVER after reading that one of the reasons you round them is to see what they will look like ....I may be converted. Too many times I've got a pen roughed out and wished I'd have cut it or oriented it differently.
Join the club! I can't remember how many times I became frustrated after guessing at which end of a blank would look best as a cap or bottom then cutting, drilling a blank in the vice, glueing the tubes in, squaring the ends and putting it on the lathe turning it down only to find the "inside" of the blank wasn't as nice as the outside!

I sure wasted a lot of good glue and tubes that way!
 

leehljp

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'Bout time someone did full a tutorial with picts, and it couldn't have come from a nicer guy! :rolleyes: :wink: :biggrin: Thanks and congratulations for doing such a great job!

Sure was nice looking at all the picts and I am sure this one will be linked in answers to TBC in the future.
 

cnirenberg

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George,
This is one of the best tutorials I have read in a while. Fantastic job. And for the doubters, just look at the quality of the pens that are produced. I am a bit jealous of the fridge, but hey I have a washer/dryer, 3 bikes, a water heater and everything else that doesn't fit in the house in my garage...er, I mean my shop.
 

Len Shreck

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I see the Pen Pal in the online catalog but can not find it to order. I looked in the index and all threw the site the only place I see it is in the online catalog so I guess I will have to call them and see whats up. Thanks for the link. Len
 

jleiwig

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George,

Is your dead center a special one? Mine barely stuck out an inch out of my headstock, but yours seems to stick out a couple inches at least, if not more. That would make my life so much easier if I had one like that.

Also If you like I can put this into a document for Keith to send to the library.
 

SonOfMartin

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Could you post some information about your sander and busing adapters? That looks like a great idea (which of course I want to 'borrow')!

Please?
 

HSTurning

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More or less ho I do it.
I don't use a pen pal I just use a utlity blade and just scratch a line from corner to corner.
I drill on a drill press and glue the tubes in to the square blank. I do like the idea of seeing the rounded blank first. I just need to save up some money for all the rest of the toys I mean tools I need/want.
I don't use the skew to clean up the CA I just start with a rougher sandpaper. I was thinking of getting a scraper or modifying the flat skew I don't use anymore to do the same thing.
 

Jmhoff10500

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Dang, out of all the tutorials i have read this was the one that eliminated the most of my questions. It covered:
Turning Between Centers
Ca Finish
What sandpapers to use
Pen layout
Clean up
and not to mention an awesome pen!!! Thanks!!!
 

dustmaker

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I am not yet turning between centers, but intend to after the holidays when a little more cash frees up. I have, however, been using the skew to smooth out the CA based on one of your earlier posts. It works great. I can get everything smoothed out and can go directly to MM. I think it makes the process easier and may save a few minutes of sanding time.
Great tutorial. Thanks for taking the time and effort to put this out for all the rest of us.
 

hilltopper46

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Great tutorial!!

For those (like me) to whom it is not obvious, the center punch treatment may not be appropriate for brittle acrylic blanks. It's a sick feeling when you see a pretty acrylic shatter when you center punch it (DAMHIKT).

The alternative is to cut it square as possible - I have even chucked it up and faced it with a sharp parting tool to give the center drill bit a nice square surface to start on.
 

Daniel

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Great job George, But what sort of shop has a fridge? I already had my doubts at that point but then when you get to the part of things wondering around to actual useful places I realize that you are full blown denial about owning a shop at all. Things migrate in my shop, but only to nooks and crannies I don't even know exist.
 
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