Preventing micro blow out around bushings

[stryker4002]

Greetings I am new to pen turning and have made about 15 pens. I have the ca finish going pretty well. I am having trouble with Micro blow out and chipping around the bushings. Someone please give me some advice as to how close I should be going to the bushings, what tool to get there, and how to prevent this problem. I would appreciate any help . Thanks much Denny

 

[Woodchipper]

Good question. I'm anticipating the answer for me, too.

 

[magpens]

A bigger picture would help, please. Can't see much in the one you posted.

Welcome to IAP, Denny !!!!

Introduce yourself in the "Introductions" forum and you could win a prize drawing at the end of the month or next month.

 

[Charlie_W]

Also, if you could tell us your process for turning, such as what tool you use, sanding, finish, etc, then we may be able to be more helpful.

 

[KenV]

Chipping at the end comes from unsupported material.

If you are cutting into the bushing, especially if the edge could be sharper, your chance of tearout or chipout go up fast.

I put on the mageyes and have the calipers out to check dimensions.

My usual tools are a curved skew and a Stuart Batty negative rake scraper. Lead from the bushing side with small shearing cuts. When as close as you feel confident, use the negative rake scraper to sneak up on the dimension needed.

Almost never have chipout even with chippy inlace acralyster.

 

[RobS]

agree with Ken

I would also add, tools transitioning from sharp to so so, will exacerbate this problem. Make sure the tool is fully supported, bring that tool rest in as close as possible so you are supported, if you are away from the part you could have tool movement which leads to catches. This works well for carbide. if you are running HS, one of the others should comment on tool support distance since I can not.

 

[leehljp]

Dull tools -> sharpen them more often. I keep super fine sandpaper near my work and wipe the blades two or three times across the SP about every minute.

Part two: I use the TBC - Turning between centers so that CA does not stick to the bushings. I also have a Rick Harrell barrel sander to sand down the ends smooth with the tube. This eliminates the cracking/chipping on the ends.

 

[gtriever]

I have read someplace recently that applying a soaking coat of some thin CA at the ends of the blank, around the tubes, prior to turning will help prevent chipout. Maybe some of the experienced turners here can comment on that?

 

[randyrls]

I have read someplace recently that applying a soaking coat of some thin CA at the ends of the blank, around the tubes, prior to turning will help prevent chipout. Maybe some of the experienced turners here can comment on that?

Art; Yes, I do this on materials that splinter. Make a puddle of thin CA on a plastic baggie, dip the end in the puddle, let dry and make sure no CA got into the tube. This only works on wood or porous materials, not plastics.

 

[wouldentu2?]

If we are talking about the CA chipping when removing from the bushings, every 5 coats remove the blank from the bushings and clean up the end of the blank on sand paper.

 

[chartle]

If we are talking about the CA chipping when removing from the bushings, every 5 coats remove the blank from the bushings and clean up the end of the blank on sand paper.

you can also use non stick bushings when doing a CA finish.

and then use a sanding mill to finish the ends. Also how to you mill your blanks before turning.

 

[rd_ab_penman]

To solve your problem do all your finishing between centers without bushings. For CA finishing smear some paste wax on you live and dead centers.

Les