1st Mandreless Pen

[tbroye]

I am making 8 Sierra/BOW Pens for members of our Church Council. I turned the 8 blanks on a mandrel 2 at a time. When it came time to assemble them I found one end on 4 of the blanks were out of round. Started checking and found a difference in the ID of the tubes and how they fit the bushing. Some were tight and others were loose. Ordered 2 sets of new bushing from AS and found the same problem. So I made up a new blank and rounded it off using the Mandrel and then finished it using the Live/dead center method with the bushings. Came out perfect and extremly smooth no sanding required. Applied a 6 coats of thin CA sanding with 600 wet dry paper bdtween coats and finished with MM it to 6000 and perfect, not too dull not too glossy. Assembled the pen and nice fit. i think the blank I had problems with were the ones closest to the tail stock and on that end of the blank. Between the bushing, ID of the Tube and the mandrel is what caused the problem. Next get a good caliper and try turning with just the centers. Now to turn 3 more blanks and I will be done, might try to sand the out of round blanks to see I can get a better fit on the out of round end

 

[hehndc]

Good lesson learned,

Steve

 

[leehljp]

Tom,

I usually go against the grain on some things and one area in particular - I always bought extra bushings. I found early on that no matter who I bought from, I had 1 in 3 Off Center enough to aggravate. So anytime I bought a set of bushings, I usually bought two sets.

Next things to do is this - if you don't have a complete set of bushings for your pens, order a set from Johnnycnc or Paul in OKC.

Turning square blanks down to size really needs bushings. They can be turned down from square without bushings - but small catches cause slippage, and slippage flairs the ends. Once it gets to near size, then I take the bushings off.

 

[tbroye]

Lee

I usually buy extra sets of bushings. In this case I had 3 set already but they were well used. So to be on the safe I bought 2 more sets and had the same issue. Using new tubes the busing still didn't fit tight on one end. I have ordered some bushing from Paul in OK and will take your advice as far as turning. I think the problems was compounded by trying to turn two blanks at once and the one on the end of mandrel closest to the tail stock was area involved. Thats where I get the greatest vibration even with a 60deg live center. Thinking about it, I wonder if using this mandrel, the original one I bought and used wiht the OEM live center is an issue as it wore to the angle of that live center and wasn't 60 deg like the new one.

While watching the Colts/Charger I came up with a thought and at 1/2 time, I went out to the shop and tried it. I took a old 1/2" metal working counter sink and laid it along side my dead center and a 60 deg triangle. The angle look the same so I put a bushing in the pen vice and counter sunk the end on two of them. The dead and live center now fit farther into the bushing and made a much better setup for Mandreless turning. Next time I am going to chuck it up in the lathe and do it that way, should be more accurate.