Scraping bushing?

[Woodchipper]

Can't remember where I had done this before but thought I would let the members comment. Am I the only one who lightly hits the bushings? I thought that it would work if a wrap of masking tape around the bushings would allow for final fit of the blank. Some turn to close tolerances and switch over to another method for final dimensions based on the bushing diameter and pen part diameters. Thanks.

 

[jttheclockman]

I never use bushings for final measurements. I learned very early in my pen making career that it is such a waste of time in accuracy why bother. No way you are going to get final dimensions with tape. use a set of calipers and become that professional pen turner we all strive for. I said this many times here I purposely turn my bushings down a little so that I get closer to a final measurement before switching to calipers. I do not trust bushings. In all my years I have never found a set of bushings that match the exact size of the components. Now if you are one of those that close enough works for you then go for it. I am not in that camp. Good luck and happy turning.

 

[bugradx2]

Oh man, this will be fun to watch. (if your bushings aren't measuring correctly then it's time to replace)

 

[howsitwork]

I never use bushings for final measurements. I learned very early in my pen making career that it is such a waste of time in accuracy why bother. No way you are going to get final dimensions with tape. use a set of calipers and become that professional pen turner we all strive for. I said this many times here I purposely turn my bushings down a little so that I get closer to a final measurement before switching to calipers. I do not trust bushings. In all my years I have never found a set of bushings that match the exact size of the components. Now if you are one of those that close enough works for you then go for it. I am not in that camp. Good luck and happy turning.

I make my own to match the kit ( measured with micrometer not calipers ) then mark up so I know what goes with what.

I do usually check the kit parts just to be sure I'm right before starting each time though

 

[egnald]

I compare the published bushing diameters with the measured diameters to decide if I need to replace them or not. I also compare the measured bushing diameters with measured diameters of the kit parts that they are going to mate up with. And finally, I estimate the diameter that the blank needs to be turned to compensating for 2 x the thickness of the finish I am going to apply. (I estimate this finish thickness by using empirical measurements of blanks both before and after finishing and then averaging based on the variance that occurs due to the materials and my specific regimen). I know it sounds like a lot, but it really isn't.

I have found that the published technical drawings for most of the bushings I use have a tolerance of +/- 0.005".

Dave

 

[Woodchipper]

The pen I turned last week was turned with calipers measuring the pen components. The bushings were a guideline. The tape idea was just that...an idea. I have some Slimline bushings that have lost a lot of metal over the years. Used merely for "rough" turning. Now I'm finding myself going with calipers and pen components.
Dave, good idea of compensating the diameter of the raw blank and adding the coats of finish.

 

[KenB259]

I have a small whiteboard, on a wall near my lathe. I write the dimensions I need on it, based on the actual pen components. I only measure the bushings to make sure the blank is oriented correctly on the lathe. I never go down to the bushings, just close, .020 - .030 proud or thereabouts. From there, I switch to a live and dead center, no bushings, measuring often, until I'm where I need to be. You also have to be aware of what component is next to the wood, a clip for instance. Don't measure the finial when the wood butts up to the clip first. The actual size of the bushings are insignificant.

 

[leehljp]

Woodchipper: "Some turn to close tolerances and switch over to another method for final dimensions based on the bushing diameter and pen part diameters."

No, I do not ever make the final dimension based on the bushing diameter. Bushings shrink. Scrapping the bushings is a fact of life in the pen world for most makers, probably 99%. About 15 to 18 years ago, someone here said that bushings should be considered as CONSUMMABLES - for the very reason you wrote. The bushings get nicked or sanded. Tape is not going to prevent that. (There is one way that bushings are not worn down and stay pristine - take them off before finishing to size.

So we either have to accept that we will nick them and they wear down, and then replace them with new ones, OR as mentioned several times above - write the size of the nose cone fitting, center band fitting (if it has one) and the clip end fitting and measure with a good set of calipers, and go by that.

I did not choose to "Switch over to another method" for the sake of doing something different. I chose (and choose) that because:
1. I wanted the connections between sections to have a smooth transition and fit,
2. I didn't like the idea of my pen turnings to be sized by a diminishing bushing,
3. I didn't like sanding dust on a fresh turned blank
and
4. I did not like bushings and blanks being CA'ed together at the final sizing and having a specific problem that arises from that. (Not everyone will have this last problem - which is more pronounced with oily blanks, particularly oily ebony blanks. This last problem listed is what brought the "switching to not using a bushing for final sizing and finishing" to this forum originally.)

I have a notebook with the all the pen instructions of the pens I have made - going back to 2005.Then, sometimes around 2006, with the wisdom given on this forum from some of the best, I began measuring with a good set of calipers and writing the measurements down on the instructions. ON Occasion, there may be a change in size and if I notice it I will write down the new measurements.

 

[jttheclockman]

I too write the sizes down on instructions but again for every pen kit that crosses my lathe I never trust any measurements because not all kits are the same. One can have more plating than another so I measure each kit I make. I never take in consideration layers of CA because to me they are not relevant for I do not do alot of coats. We all develop our own methods that work for us. With these things in mind and as often as this question comes up here all I can suggest is read everyones ideas and develop your own method. Use bushings or not. calculate layers of finish or not. Just try to shoot for a smoothe transition from blank to kit parts. Good luck.

 

[Smokey S]

When I first started I utilized the bushings for sizing and I ended up with some shop pens due to the incorrect sizing for the transitions. It didn't take me long to start using the dial calipers religiously! …………Smokey