Turning & Finishing "Mandrelless???"

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tgraytn

tgraytn

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I read a thread a while back regarding turning and finishing pens without a mandrell. The picture that I saw looked like the bushings and the pen blank was held between a fixed 60 degree shaft (where the mandrell would normally fit) and the live center on the tail stock. Is this correct? Also, is it preferred over the use of a mandrell as far as turning and finishing? How will this work on a Euro pen kit where the bushings do not fit into the pen tube? Thanks!
 
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Tom,

I would like to clarify a couple of items that sometimes gets missed:

1. You can only do one blank at a time. Most people notice this but occasionally that gets missed.

2A. Use the bushings on the blank to turn it down to near size;
2B. Take the bushings off and just place the blank between the centers without the bushings for finishing. No stuck bushings, no bushing dust on the blanks, no chipped CA.

Use calipers to measure the fittings and then size the blank at final sanding.

Another note, after no more than a couple of times of using TBC, it is so fast in removal and set up that changing from bushings to no-bushings is only 5 or 6 seconds. Almost nothing when compared to mandrel setup and take down. Most people find that very helpful for removing a fine or delicate blank two or three times for inspection during the turning process - something that is a bit of a bother to do with a mandrel.

While a mandrel setup can run true and works for many, it has more parts and potential for problems than the fewer parts of TBC. I can remember only one person who said they tried it and went back to mandrel; but just about everyone else who goes this route loves the simplicity and greater overall precision.
 
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Actually, you're not limited to one blank at a time - you can always buy another set of bushings >:-p

And you can use the 'plastic' bushing Johnny makes to avoid the glued bushing problem (or even turn your own!!!)

Not being rich though, I just do one blank at a time...

Marc

leehljp said:
Tom,

I would like to clarify a couple of items that sometimes gets missed:

1. You can only do one blank at a time. Most people notice this but occasionally that gets missed.
Click to expand...
 
And the newbie who just ordered calipers wants to clarify, you can turn without bushings, using the calipers to check your dimensions, right?
 
PaulSF said:
And the newbie who just ordered calipers wants to clarify, you can turn without bushings, using the calipers to check your dimensions, right?
Click to expand...

That's the best way. No matter what the bushings measure, it you measure
the pen parts themselves, you're guaranteed a better fit.
 
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PaulSF said:
And the newbie who just ordered calipers wants to clarify, you can turn without bushings, using the calipers to check your dimensions, right?
Click to expand...

I'd actually really like to see someone attempt this:eek:
Ok SOME bushings may be a tad off, but surely they are better than nothing? I say you compare your bushes to the kit with your calipers and compensate accordingly, but use them ( the bushes )anyway
I can't see how anyone can get enough grip with just centres without flaring the tube?

and even when it comes to finishing, what stops the finish from filling up the step between the blank and the centres?
I just don't get it:confused:
 
skiprat said:
I can't see how anyone can get enough grip with just centres without flaring the tube?
Click to expand...

When I'm putting on a finish, there's not much pressure. But I probably do
flare them somewhat. I never really checked.

I don't go without bushings altogether, but I seem to have enough trouble
getting the CA off of the bushings that it's just easier for me to apply it
between centers. I go back on bushings to polish. I have a whole container
of 'glue bushings' I keep meaning to clean. :tongue:

I don't seem to have a problem with CA filling the gap, though. But I tend
to put it on in light coats so there isn't that much getting pushed out past
the ends..
 
Charlie, I wasn't trying to single you out:wink: I've read posts where it seems that the turner claimed they could simply jam the still square blank between centres, grab a skew and whip it down and just check their still perfectly square ends with a vernier caliper. Then sand it ( not much ,cos they got a near perfect finish with the skew :wink: ), slap on a mirror shine CA/BLO/CA finish all in about 32.65 seconds!!!

..and then moan like hell cos they can't get more than 30 bucks for an Emperor.
Gee, what's the rush and where's the fun:confused::biggrin:

Right, I've had my little hissy fit:biggrin:, I'm going for a pint....:tongue:
 
LOL .. well, I haven't turned without bushings except for resin or stone, but
you lost me at the 'grab a skew' part anyway.

The only thing I can do with a skew is catch.. or remove a good finish when trying
to score the CA between the bushings and the blank.. :tongue:
 
NewLondon88 said:
The only thing I can do with a skew is catch.. or remove a good finish when trying
to score the CA between the bushings and the blank.. :tongue:
Click to expand...

LOL, then you and I have something else in common. I have two skews and they are stored next to my 'difficult to open paint tins':biggrin:
My lathe cries like a baby when it sees me hold one, or it could be laughing...
 
marcruby said:
Actually, you're not limited to one blank at a time - you can always buy another set of bushings >:-p

And you can use the 'plastic' bushing Johnny makes to avoid the glued bushing problem (or even turn your own!!!)

Marc
Click to expand...

Marc,

Since this thread is about TBC/Mandrel-less, my comments were in line with this thought. There was a fellow recently that said he was having trouble keeping the blanks on the lathe in TBC, even though he had the tailstock up tight. As soon as he turned the lathe on, the blank would fly out. . . Turns out he put the two part blank set end to end and jammed them together with the tail stock. Of course it is going to fly out once the lathe is turned on. :biggrin:

. . . Therefore, my note was written on the basis of preventing this kind of "thinking" from happening. "One blank at a time on the lathe" in TBC.
 
skiprat said:
Charlie, I wasn't trying to single you out:wink: I've read posts where it seems that the turner claimed they could simply jam the still square blank between centres, grab a skew and whip it down and just check their still perfectly square ends with a vernier caliper.
Click to expand...

I have read those too, and I cringe. I always (as in my first post on this thread) say that it is a two step process with TBC.
1. With the bushings to turn it down;
2. Without the bushings for finish.

You asked the question about getting CA on the "centers" instead of the bushings. Yes, that happens, but it does not cause anywhere near the problems as when the bushings and blank are butted up next to each other and are level with each other. A second part to this is that the problems don't happen nearly as much on thin coatings/finishes as it does on thickly built up finishes.


Then sand it ( not much ,cos they got a near perfect finish with the skew :wink: ), slap on a mirror shine CA/BLO/CA finish all in about 32.65 seconds!!!

..and then moan like hell cos they can't get more than 30 bucks for an Emperor.
Gee, what's the rush and where's the fun:confused::biggrin:

Right, I've had my little hissy fit:biggrin:, I'm going for a pint....:tongue:
Click to expand...

I hear you! :eek: :biggrin: I still have not learned to do the skew correctly in that little bit of space. I keep thinking I need a smaller skew. I even have the DVD, but my hands can't seem to hear or see the pictures/video. :eek:

Just a note - there are situations that require a finish on the wood in which sanding/buffing/burnishing can not do. If anything other than the chisel and finish touch the bare wood, it will cause major problems - some metal and wood segments and some wood to wood segments.
 
Marc Phillips said:
I use the bushings from John... JohnnyCNC here... you are correct about the set up... the fixed 60 degree shaft you are talking about is called a dead center...

http://penturnersproducts.com/index...Path=2&zenid=a1c01feba47e0b31c3a5d8cd39d1453e
Click to expand...
I guess I am pretty dumb. I need the "dead center" as the other end to the 60 degree "live center". I went to Woodcraft (as I need to return one live center) and cannot find a listing for a dead center. What do I use??
 
I just purchased my Dead Center from Pen Turners Products. Here is the link:

http://penturnersproducts.com/index.php?main_page=product_info&cPath=5&products_id=115

Here is a picture of it:

Dead Center.jpg

Here is a picture as set up on a lathe:

Dead Center On Lathe.jpg
 
Jgrden said:
I guess I am pretty dumb. I need the "dead center" as the other end to the 60 degree "live center". I went to Woodcraft (as I need to return one live center) and cannot find a listing for a dead center. What do I use??
Click to expand...

Just to set the record straight, if using regular (store bought) bushings or the turned blank ready for finishing, a 60° live center is NOT a necessity.

Here is an early one (dead center) that I turned from aluminum and the one that started me to Turning Between Centers. It is not 60°.

1_Dead_drive_1.jpg




JohnnyCNC does make the dimple holes at a 60° on his bushings, so for his, 60° is a necessity. I will add that John's is of much closer tolerances and much higher quality than the bushings purchased from stores.

On new pens that I try out - in which I buy two to four, I get a set of the store bushings. If I like the pen and plan on doing more, I purchase the higher quality bushings from John.
 
Well guys, I am one who doesnt always use bushing when turning between centers. :cool:

I bought a few long click kits but forgot to buy the bushings. I needed to make a Birthday gift and a PITH pen and couldnt wait. just squared the ends of the long clicks and went at it. I cant use a skew for the life of me so I used my trusty woodchuck all the way down to final diameter with calipers. No bushings at all.

Did get some catching but not much and didnt get any flairing of the tubes. I just recieved my bushings for the long click yesterday but I have already done a few long clicks PR, maple, Bubinga, Cactus ,Amalgamutt, Blackwood burl, without any problems. The inside of the tubes do get chamfered a bit but nothing serious to cause problems.
I did go slow and tried to keep in mind about flairing the ends but I think I may have been worried too much about the CA finish to even think about the tubes. Got my CA finish down(still needs some work) and sanded the ends to remove the CA buildup.

Works for me.:biggrin:
 
Lupe,

Congratulations of being able to do this without a problem. Glad it works for you. I "can" and have just to see if I could, but it is not easy without chamfering the inside or flaring the tubes for sure.

About 30 years ago, I read an article about mountain climbing at the Matterhorn. When a park ranger was asked the most dangerous aspect of climbing the MH, he replied: "The most dangerous aspect is the one person that starts and makes it up to the summit and back in one day. After such a successful ascent and descent, the news will, for several weeks push many unprepared people to attempt the same, only to get caught in sudden storms, or have other mishaps and end up with major injuries or death." (A lot has changed since then with trails, starting points and controls.)

And the point of the analogy: Turning a pen without a bushing is not dangerous like that, but I have been surprised at the number of people who make difficult work of things that are simple for others or at least a few. There is simplicity in "No bushing" turning and you mastered it for you, but it ain't simple for others. Shucks, some people flare the tubes when simply "finishing" without bushings.

When some people can't duplicate the procedure as you did, they like to blame the one that suggested it or question the integrity at the least.

I had a couple of people question my statements when I said that I could turn a blank so smooth that it did not need sanding before applying finish. Even with the a picture of the finished pen, I am sure they still had their doubts. Sometimes, I just keep my mouth shut or not write about something because I know the explanations will be questioned and I will be blamed for it not working. But hey, thats life! :cool:
 
Hank, I too regularly do not sand before my CA finish. I dont have your skill though.
Im just afraid I will leave sanding marks under the CA.:biggrin:

Yep thats Life:cool:
 
Rifleman1776 said:
Lotsa replies here. I haven't read most.
Hank nailed it. Really, nothing more to be said.
Click to expand...

So why reply?



My take on it is that if your flaring the ends of your tubes to a large degree that it's easily noticible- then you have the blank too tight.

Loosen it up a bit, sure you'll get it to stall a bit every now and then, but not all the time, and I always saw it as a plus to prevent a catch on an expensive blank or finicky burl to have the whole thing stop spinning instead of the tube still spinning and the wood nowhere to be found. :biggrin:
 
As a relative newbie to pen turning, I just learned about mandrel-less pen turning yesterday and haven't yet tried it. I'm wondering if the 60 degree specification for the centers is any kind of advantage for TBC turning. It would seem to me that a much pointier center would give you more room to work at the ends of the blanks and might even provide a better grip on the truning blank.
 
tstagl said:
As a relative newbie to pen turning, I just learned about mandrel-less pen turning yesterday and haven't yet tried it. I'm wondering if the 60 degree specification for the centers is any kind of advantage for TBC turning.
Click to expand...

Yes, because the inside of the 'good' bushings are machined with the
60 degree centers in mind. They will fit the centers correctly.

tstagl said:
It would seem to me that a much pointier center would give you more room to work at the ends of the blanks and might even provide a better grip on the truning blank.
Click to expand...

I think a 'pointier' center would have less surface contact with the
bushings, providing less drive. Probably more likely to give you an out
of round blank due to the play possible in the centers
 
I turned my first between centers turnings without bushings. I had accidently bought a set of tropical sierra bushings instead of the regular bushings. So I just took it slow and measured after every pass once I got close to kit dimensions. It was a bit of a pucker factor, and I have never done it since, but it can be done without much harm.
 
leehljp said:
Tom,

I would like to clarify a couple of items that sometimes gets missed:

1. You can only do one blank at a time. Most people notice this but occasionally that gets missed.

2A. Use the bushings on the blank to turn it down to near size;
2B. Take the bushings off and just place the blank between the centers without the bushings for finishing. No stuck bushings, no bushing dust on the blanks, no chipped CA.

Use calipers to measure the fittings and then size the blank at final sanding.

Another note, after no more than a couple of times of using TBC, it is so fast in removal and set up that changing from bushings to no-bushings is only 5 or 6 seconds. Almost nothing when compared to mandrel setup and take down. Most people find that very helpful for removing a fine or delicate blank two or three times for inspection during the turning process - something that is a bit of a bother to do with a mandrel.

While a mandrel setup can run true and works for many, it has more parts and potential for problems than the fewer parts of TBC. I can remember only one person who said they tried it and went back to mandrel; but just about everyone else who goes this route loves the simplicity and greater overall precision.
Click to expand...


Well here is newbies dumb questions:

I am confused as to how to use stock bushings (ie: euro don't fit inside the tube) how would you use them? Sorry for what might be really dumb.

While I'm posting-- what does CNC stand for? and PITH.

Thanks,

John
 
Thanks for the reply, Charlie. I guess I didn't mention it, but I was talking about mandrel-less turning without bushings. I was talking to an experienced turner the other day and he says he doesn't use mandrels or bushings anymore, just a good caliper. In this case, I was thinking that a pointier center would give you more working room at the ends of the blanks.
 
jocat54 said:
Well here is newbies dumb questions:

I am confused as to how to use stock bushings (ie: euro don't fit inside the tube) how would you use them? Sorry for what might be really dumb.

While I'm posting-- what does CNC stand for? and PITH.

Thanks,

John
Click to expand...

The 7mm pens are the only ones that you would need to buy bushings from someone like JohnnyCNC to turn between centers. All the others that fit inside can be used.

CNC stands for Computer Numerical Control. It's become a common term to indicate a computer controlled machining center, but many things can really be considered CNC, not just machining related items..

PITH stands for Pen In The Hat.
 
Ah.. without bushings. Well .. be very careful.. it's easy to flair the tube, which
can crack your blank. and in that case, you could probably make yourself a wooden
or Delrin dead center for one end.. then flip the tube to do the other end.
Bushings might be easier and less expensive though..
 
jocat54 said:
Well here is newbies dumb questions:

I am confused as to how to use stock bushings (ie: euro don't fit inside the tube) how would you use them? Sorry for what might be really dumb.

While I'm posting-- what does CNC stand for? and PITH.
Thanks,
John
Click to expand...

John, I know that PITH and CNC have been answered but I will give you a link to a thread with other Acronyns used here:
http://content.penturners.org/articles/2009/Acronyms.pdf
. . . and I use this link to find other acronyms:
http://www.acronymfinder.com/

Now, as to your question about using standard mandrel bushings on TBC - I have a four picts posted below to show the simplicity of it.

Both custom and standard mandrel bushings are shown laid out:

1_Mandrel.Custom_bushings_TBC.jpg




Here are the custom bushings on the lathe mounted between the centers:

1_Custom_Bushings__2_TBC.jpg



And Here (below) are the standard/mandrel bushings on the lathe mounted between the centers (looks the same doesn't it? - Works the same):

1_Mandrel_Bushings.jpg



Compare the above layouts to the layout of a mandrel:

1_Mandrel.jpg



What it comes down to is that both kinds of bushings will work for the TBC setup. When TBC took off, custom bushings were not available so people used the standard mandrel bushings.

I will say personally that if the tolerances of commercial mandrel bushings were to be compared to custom bushings, the custom bushings would be greatly appreciated, . . . but they are not a necessity. IF using the standard bushings, I recommend that two sets of commercial mandrel bushings be purchased and the fittings checked to get one pair that fits reasonably well.
 
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leehljp said:
John, I know that PITH and CNC have been answered but I will give you a link to a thread with other Acronyns used here:
http://content.penturners.org/articles/2009/Acronyms.pdf
. . . and I use this link to find other acronyms:
http://www.acronymfinder.com/

Now, as to your question about using standard mandrel bushings on TBC - I have a four picts posted below to show the simplicity of it.

Both custom and standard mandrel bushings are shown laid out:

1_Mandrel.Custom_bushings_TBC.jpg




Here are the custom bushings on the lathe mounted between the centers:

1_Custom_Bushings__2_TBC.jpg



And Here (below) are the standard/mandrel bushings on the lathe mounted between the centers (looks the same doesn't it? - Works the same):

1_Mandrel_Bushings.jpg



Compare the above layouts to the layout of a mandrel:

1_Mandrel.jpg



What it comes down to is that both kinds of bushings will work for the TBC setup. When TBC took off, custom bushings were not available so people used the standard mandrel bushings.

I will say personally that if the tolerances of commercial mandrel bushings were to be compared to custom bushings, the custom bushings would be greatly appreciated, . . . but they are not a necessity. IF using the standard bushings, I recommend that two sets of commercial mandrel bushings be purchased and the fittings checked to get one pair that fits reasonably well.
Click to expand...


Thanks Hank.

Still not getting it yet. What holds and centers the stock bushings (slimline-euro) to the blank.

Sorry for being so slow on this.

Great pictures though.

Thanks,

John
 
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