Getting the nip part right

Signed-In Members Don't See This Ad
Cherie

Cherie

Member
Joined
Feb 22, 2010
Messages
206
Location
Pomona, Missouri
I seem to be having problems getting the nibs and the wood and or acrylic to come out flush. I have calibrated and did everything I thought possible and it still does not come out. This is on the European kits.
 

Attachments

  • P1160736.jpg
    P1160736.jpg
    25.9 KB · Views: 263
  • P1160737.jpg
    P1160737.jpg
    21.2 KB · Views: 300
  • P1160738.jpg
    P1160738.jpg
    22.8 KB · Views: 200
Signed-In Members Don't See This Ad
I suggest you get some calipers and quit relying on the bushings. Bushings are inaccurate at best. Unless the are custom made and even then the kits could vary slightly from one production run to the next.
 
Doesn't one need a flask to get the "nip" part right?

On a serious note; are you overturning (meaning the pen barrels is a smaller diameter than the nib) or underturning (the pen barrel is a larger diameter than the nib)? Is it consistent around the circumfrence (meaning is the off by the say amount for the entire 360 degrees) or are there spots where its fine and spots where its either overturned or underturned?

EDIT : Sorry I missed the pics before, I see you are overturning.
 
Last edited:
The first thing i would do is get a set of digital calipers. I use a $10 set from HF on sale. Set zero on you nib. Then for acrylics i turn the to .1 - .15mm larger than the nib or any other piece and sand from 600 wet down to 12k MM. I try to start the mm at about +.06mm and the mm should eat through the rest leaving you pretty durn close to flush.

For wood I over turn the piece about .1mm and build back the ca to +.1-.15mm and sand down as above. This will make sure all ridges are sanded out. With this i dont count coats of ca instead i shoot for a specific thickness of .1-.15mm thick when finished.

I hope this helps. When i switched to digital calipers it totally changed my fit because it was so much easier to put an exact number on everything. I now have multiple sets.

For this pen i would take it apart and build it back up with ca if it is not to far gone. You can trim the barrel too and adjust the tranny accordingly.

After though. I just reread and you said you are using calipers. Where are you measuring on the blank? since you are tapering the blank your calipers should just barely be on the blank. Also the spot where you zero the calipers should be the same spot you place your blank in case there is a difference. Many times i remove.the blank and hold it to the light to make sure the calipers are just touching the blank. These are just my steps and others will vary.
 
Last edited:
You can determine where you are going wrong by doing self analysis. It is obvious, just by looking at the assembled pen, that you over turned the barrel. Do you get caliper readings on your finished pen that tell you the barrel is the right size, even though it is not? That would indicate your measuring technique is incorrect. As mentioned already the measurements need to be taken so the caliper jaws rest at the very end of the barrel. I have found that removing the blank from the lathe (repeatedly) to take measurements as you get close to the final desired size allows much more accuracy. Try that, and hopefully it will clear up the problem on your very next pen. Happy turning!
 
Plus 1 on the calipers. And plus 1 on the CA build up to bring it back to size.
Done that often and not hard to do.

For calipers, a good set can be had from Harbor Freight for reasonable prices. Measure the nib, write the measurements down and then turn and measure, turn and measure, creep up on the intended size to CA.
 
I use calipers as well. With acrylics I measure the kits and then aim a little larger. Then I sand down to final. With wood I aim right at the size of the hardware then sand below my target then build back up with CA
 
Cherie, I find that that cotton picking nib is hard to get a good reading on with calipers. I try to read it parallel with the jaws such that the nib just passes through the jaws by just touching both at the same time. The tapered end of the blank can be even worse. There you must be using the sharpened tips of the calipers. If the blank is turning, then you will cut a real nice ring into the blank, or so I have been told, I, personally would never be caught dead something so damaging. The measuring point has to be right at the end. do not feel bad about this, if it can be messed up, most likely I have already enjoyed the experience, if not, then someone else here has already beet you to it.
Charles (you should see my trash barrel 55 gal and running over)
 
ctubbs said:
Cherie, I find that that cotton picking nib is hard to get a good reading on with calipers. I try to read it parallel with the jaws such that the nib just passes through the jaws by just touching both at the same time.
Click to expand...

Try holding the nib by the nose cone with your thumb and fore finger and measure from the press fitting side. This is the measurement you want as this is where the nib meets the barrel. Use the same holding technique for the finial as well.

ctubbs said:
The tapered end of the blank can be even worse. There you must be using the sharpened tips of the calipers. If the blank is turning, then you will cut a real nice ring into the blank, or so I have been told,
Click to expand...

Don't measure with vernier style (digital or analog) calipers while the lathe is turning.

You can damage your blank by scratching it, those sharp points are sharp enough to scratch.

The jaws can catch and you will need a new set of calipers.

This is a delicate instrument and excessive wear from rapidly spinning objects will negatively affect your measurement and possibly cause wear on the machined surfaces of your caliper.

Do measure from different angles. Take a measurement and take note, rotate the blank by hand 1/3 or so revolutions and measure again, repeat process, this is a good way to check if you are going out of round.

I also recommend switching to finishing bushings at the point where you start to measure with calipers. This not only adds the clearance needed for finishing but also provides more clearance for the calipers as well.

Just my thoughts on measuring. I have stopped purchasing bushings and make my own finishing bushings. There are lots of posts and articles on this.


Terry
 
I did try something different on the last pen I did last night. But first, I do not calibrate while the machine is turning, I know that is a big no no. LOL. Second, a friend asked me how I was turning and sanding at the nib or even the clip part. I was going from the bushing inward, well he suggested that I go towards the nib. It worked great. The last pen I did last night would have been my best European pen yet, except there was an air bubble in the acrylic leaving like a white hole there. I was not happy with that. Oh well. I am learning and I thanks each and everyone of ya's for the comments and advice.
 
Tapered bushings tend to wear from sanding. As an alternative to everything that has been suggested you might try this. Cut the blank about 16th longer than needed. Square only the nib end. Slightly overturn/sand the nib end. Measure the diameter of a scrap nib that you have filed the fitting down so that it can easily slide into the barrel before assembly. Using the digital caliper measure the diameter of the scrap nib for reference. Then measure the diamter of the nib from the kit. Using these two measurments as a guide snad the nib end down on a disc sander while turning the barrel in your hand. Do this gently and check the fit with the scrap nib. After you have acheived the proper fit for the nib end use a spare tube to the check the overall length. Sand the other end of the barrel on the disc sander to the length of the spare tube. These are some extra steps but will give you a near perfect fit on taperd barrels.
 
You must log in or register to reply here.
Back
Top Bottom