TBC

[charliekap]

I just started to TBC. I am using digital calipers to get to the correct size. I wouldlike to present an example of my question. I am currently turning a Gatsby pen. I measured to two compenents that will touch the blank and they measured .507 and .504
To what measurement do you turn the blank to before beginning sanding. Is it different for different materials? How much under pen component size do you go to allow a finish buildup. For this particular pen, I will be using the StickFast CA Finishing System.

Charlie

 

[Lenny]

I like to stop turning slightly above the finished size ... (say .511 for finished size of .507) then sand to slightly udersized ... lately I have been really having to build back up with CA to get to the correct size.
Experiment by taking measurements (record them instead of trying to remember them from memory like me ... failing memory I might add) along each step of the way and you will soon get an idea of what works for you. We each sand differently, do our CA differently etc. Especially pay attention to what your measurements are before CA, After all coats of CA and then the final measurements after sanding the CA with Micro Mesh.

 

[woodgraver]

Charlie, if you experiamented with your finish by taking a reading before applying it and one after you finish the process you will be using, that would probably give you the most accurate answer. In practice, my TBC busihings are .475". I will turn the blank to just slightly proud of them and then sand using abranet until I'm flush. I then put 4 to 5 coats of medium CA on with accelerator inbetween coats and perform the normal final sanding with one pass from 400 abranet and then a pass each through the micromesh from 1500 - 12000. I'm always very happy with how they mate up with my components for Gatsby/Sierra pens.

 

[mdburn_em]

It depends

You question depends on 2 things.
1. How "smooth" is the blank once you are done with your lathe tool?
2. How "smooth" are you able to apply the CA to the blank when finishing?

I will stop about .001 - .002 proud of my final measurement. I begin sanding with 400 grit. I end up being .001 - .002 under my final measurement.
I apply 5 or 6 coats of thin ca
I begin sanding at 600 or sometimes 800 grit paper - 2000, then MM 4, 6, 8 & 12,000 followed by micro gloss.