Turning Between Centers

[jac42779]

I'm new to pen turning and about to attempt turning between centers. Was wandering do you just use the bushings that come with each pen kit to turn between centers or is there special bushings that you use?

 

[Jim Smith]

JohnnyCNC sells steel bushings with 60 degree angles on the ends which are much superior, but you can get by with the standard bushings just fine.

Jim Smith

 

[JBCustomPens]

You can also drill out the end of your bushings with a 60 degree center drill. You have to be careful though. JohnnyCNC offers top notch products, and I enthusiastically recommend him and his bushings.

 

[KenV]

My answer in a word is Yes

I turned a couple dozen pens in Feb with a dead center in the headstock and live center in the tailstock and regular bushings. No mandrel anywhere.

I also turned a few with custom bushings manufactured for turning between the centers, They have a bit longer stub into the tubes and are machined to match the 60 degree angle of the dead center and live center.

With a few notable exceptions where both pieces of a two piece pen need to be together, I find it a more enjoyable way to turn

 

[lwalden]

yes. you can use the stock bushings, though they have some disadvantages compared to those produced by Johnnycnc. First, they are not turned to as tight a tolerance for the i.d. of the tubes, so there is still some of the same level of "slop" with the bushings fitting slightly loosely in the tubes. I have found that one of the side benefits of using Johnny's bushings is that my tube has to be clean and the edges crisp from the pen mill or his bushings won't go in smoothly, if at all. With stock bushings and the extra "wiggle" room they give you, it's easy to miss a slight glue buildup or have a little deformation in the edges of the brass from the pen mill, and still be able to load up on the stock bushings. The downside to this is it will contribute to a slight out of round condition, and may also contribute to cracking your finished barrels when you try to press in the hardware fittings. Johnny's fit so snuggly that I now automatically hit the ends of my tubes after using the pen mill with a small manual reamer (purchased from A.S., though I believe Johnny and several others offer similar tools). If Johnny's bushings fit, I don't have to worry about anything in the tubes that could cause the hardware to deform or crack the barrels when pressed in. In addition, the stock bushings don't come with a 60 degree taper for mating up with the dead and live centers. That is not a requirement, but the down side is that you will have less surface contact between the centers and the bushings, resulting in less "grip" or "friction". as a result, you may find (especially in harder materials) that you have some slippage while roughing, and end up needing to tighten, and possibly overtighten, your tailstock and live center. On the low grade steel used for stock bushings, this can mar. Additionally, the part of the bushing that slides into the tubes is shorter on the stock bushings than it is on Johnny's aftermarket bushings. This becomes more important the more the bushing does not have a snug fit. This also contributes to out of round, in that the shorter length can act as a magnifier. Picture a piece of 1" pvc and a 1/2" dowel. The 1" PVC obviously has a larger inside diameter than the 1/2 dowel. Slip the dowel inside the PVC about 1" and slant it to the side until it is snug, and you can get a pretty steep angle. Slide it in 3" and snug it side to side and you get much less of an angle. Slide it in 6" and it is very close to parrallel with the PVC. This is where a lot of the out of round problem can come from- the combination of the loose fit and the short length inserted (all right, some of you need to quit snickering at this point and get your minds out of the gutter!!:wink. There are a variety of techniques that can be used to compensate for this- it is possible to add a 60 degree taper to stock bushings, and stopping to rotate the blanks position on the bushings themselves can help even out the OOR condition.

 

[lwalden]

Shoot, looks like while I was putting together my long-winded response, most of those same points were covered by other folks! Got to be quick around here!

 

[jac42779]

LOL thanks Lyle and everyone else for the replys! I never thought about using a center drill to cut the 60 degree angle on the kit bushings.

 

[JBCustomPens]

LOL thanks Lyle and everyone else for the replys! I never thought about using a center drill to cut the 60 degree angle on the kit bushings.

Yeah, I learned that trick a while ago. But, you must make sure that your center drill is perfectly in line with the center hole in the bushing. And it is not even worth trying if the original hole is off center. Glad I could help!:biggrin:

 

[johnnycnc]

You can use the stock bushings, yes. I started this way.
It was better than a mandrel, for me.
It did not satisfy completely, though.
I then designed and made my first special bushings and found what I was looking for.
Center drill the stock bushings if you wish, you will gain bearing surface.
Accuracy will not improve, though.
But..it's cheap!

 

[JBCustomPens]

You can use the stock bushings, yes. I started this way.
It was better than a mandrel, for me.
It did not satisfy completely, though.
I then designed and made my first special bushings and found what I was looking for.
Center drill the stock bushings if you wish, you will gain bearing surface.
Accuracy will not improve, though.
But..it's cheap!

Yeah, I totally agree. John's bushings are top notch, as are any of his products. That is the route to go if you want the best accuracy.

 

[yost69]

I havent bought anyone elses bushings except johns so I have nothing to compare to.

I have been very happy and have been slowly purchasing more sets from him as I accumulate the funds. You will not be disappointed.

Ben

 

[Tree Frog]

I bought a couple of bushing sets from Johnycnc about a month ago. I'd only used a mandrel up until then and had become quite dissassified with the out of round turnings this method produced. Started using the bushings from John and my whole enjoyment of penmaking skyrocketed because of the accuracy that they afforded me. I've done some wood, dymondwood and trustone pens since getting the bushings and I'm wrapped. Personally, I wouldn't mess with drilling existing bushing as I could end up with the similar inaccuracies as I was getting with the mandrel. So when I scuff these bushing up too much, I'll definately be buying more, they just work, and you can't do beter than that.:biggrin::biggrin::biggrin:

greg

 

[Texatdurango]

LOL thanks Lyle and everyone else for the replys! I never thought about using a center drill to cut the 60 degree angle on the kit bushings.

Jason, If you click on the IAP home page and look to the right column you will see a link to a little tutorial about turning between centers. It will show you some little tips, one being using the center drill. It might give you some other ideas as well.