Too much material left

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Woodchipper

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I just finished assembling three pens and they look like crap, at least to me. I turned down as close to the bushing but when assembled, there is a lot of material above the parts. These are WC Slimline pens and acrylic blanks. I got a PSI catalogue and saw the catalogue had a set of mandrels, P/N PKMBCM2. Are they worth it? I have considered TBC and looked at the 60 degree live center at a couple of places. Recommendations for headstock and tailstock for TBC? I need to move up a couple of steps in quality as I am picky. I have a three piece set of calipers and a dial caliper so measuring diameter isn't an issue.
 
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Talltim

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TT, how do you TBC??


I just use the regular bushings between 60 degree live and dead center.

We have invested in some custom TBC bushings which are nice and seem to be a little less wear on the live and dead center. Both work well.

We have found that all bushings ARE NOT created equal. We just returned a set to WC where the center hole on the bushing was visibly off. This will not work on any method. WC replaced it no questions.
 

eharri446

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If you are referring to the PSI Turn Between Center mandrel set for $29.99, then I have been using mine since they came out. I love them because it is almost impossible to bend the mandrel rods, even when you have big catch occur.
 

wouldentu2?

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Measure the components and turn to that size, use the bushings as a get close guide. Does anyone make turn between center bushings for a slimline?
 

glycerine

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After turning down to the bushings, I like to mount the blank (between centers) without the bushing and SLIGHTLY round the edges. That way, even if the diameter is slightly larger than the pen components, you won't feel that hard edge. Sort of like the way they have "2.5D" glass on cells phones, with the curved edges...
 

JimB

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If you only turned them 'close to the bushings' you didn't turn them enough. You also say you have the measuring tools. Did you measure your turned blank and the kit before assembling them?

You might want to dis-assemble the pens and continue to turn them until you get a fit you are happy with.
 

leehljp

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Several have mentioned "measuring" but you need something to measure with. Get a couple of calipers from HF. I would recommend getting metal ones. The two plastic (composite) ones that I bought (one from HF and one from Woodcraft a couple of years ago) they are not sturdy enough, IMO. Get stainless steel ones like the following.

https://www.harborfreight.com/6-in-digital-caliper-with-sae-and-metric-fractional-readings-68304.html

Sometimes these are on sale plus an additional 20% off with a coupon.

Measure the nib, center band and clip end. Turn the blanks to match the size of the clip end, CB and nib. I (and others) often turn it down about .003 or .004 below the size of the nibs and build it back up with CA, or other finish. If waxing only, turn to size and wax.

This is where one makes a couple of leaps in quality - by matching the blank to the fitting precisely.
 

magpens

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If you have a set of digital readout calipers and if you are using them properly, then you should be able to get the turned diameter to what you want ... for a slimline that measurement should be 0.331" (the bushing diameter).

You can do the turning between centers without any bushings at all and without the mandrels that PSI sells. I would never spend $30 for these:

https://www.pennstateind.com/store/PKMBCM2.html

I do all my turning between centers using a 60 degree live center in the tailstock and a small, parallel sided center in my headstock chuck. . This latter piece I made myself. . And I made one for each of the different pen tubes I use.

At the tailstock end, when you are turning slimlines, you will most likely jam the cutting tool into the live center because there is not much clearance. To avoid that, I don't turn down to size at the tailstock end. I do the headstock end and then turn the blank over so that the tailstock end moves to the headstock and I repeat the process at the headstock end getting both ends of the blank to the size I want.

Now ... at the all-important headstock end ..... As I said, I make a parallel-sided dead center for each different pen tube.

For example, for the slimline, I use a 3/8" rod and machine one end down to 0.325" for about 1". Then I machine a taper on that end and the tapered end fits into the end of the slimline tube. . You now have a mini dead center.

The material for the rod can be plastic (it won't last very long until you have to make a new one), or brass (you will get quite a bit more life but it too will need replacement), or steel (a very long life). You can even use aluminum but it's life will be about the same as brass.

To make one out of steel you can buy some rod at a machine shop (or some tool stores). Get mild steel, not hardened steel). Don't use your lathe tools to machine down the steel, unless you have a metal working lathe. If you pick the rod size appropriately, you won't have to take off much material and you can use a Dremel tool to take the size down (from say 3/8" = 0.375" down to about 0.325" or a shade bigger ... big enough that it won't go inside the slimline tube and small enough that it is smaller than the slimline bushing outside diameter.

Finally, do a shallow taper on the end of the rod so that the tip of the rod fits inside the slimline tube and the "inside corner" of the tube "rides" on the tapered surface.

You can do this shallow taper with a file (or Dremel tool) while the rod is spinning at medium-to-slow speed in the headstock chuck. Use your discretion making the taper.

This is really easy to do, and you can do it faster than the time it takes me to describe the process.

But the overall key to getting your slimline (or other) blank end down to the size you want to match the pen kit hardware components (or a shade bigger) is your measurement process.

Measure when you think you are close. Take the blank in your hands when you measure .... measuring the blank when it is on the lathe does not work for me. Then remount the blank, and turn a little more off the end of the blank keeping to the shape you want the blank to be finally. . Then remove the blank and measure again until you get it right (just a shade over 0.331" to allow for a little bit of sanding).

In a few minutes, you will get the hang of this. . You have to learn to use the calipers to measure VERY close to the VERY END of the blank. . You will notice that the caliper jaws have thin ends right at the open end of the jaws ... use those thin ends as close to the end of the pen blank as you can get and still make a good measurement.

This will take some practice, but it all becomes very natural quickly.

Instead of buying steel rod at a machine shop, you can buy (for slimline use) a thick building spike from Home Depot (Home Depot also sells brass, aluminum, and steel rods if you know where to look).

I hope this helps you. . As I said, I would not buy the TBC mandrels from PSI. I have not tried them but to me they just look like a waste of money. . It is the taper at the headstock end that does it for me by the method I have described. . You can also make use of the taper at the tailstock end when you are working with tubes 3/8" and bigger as long as you proceed very carefully to not jam your cutting tools into the 60 degree live center.

Measure, measure, measure !!

BTW, if you have steady hands, you can quickly grind a taper on the rod on your grinding stone, but I wouldn't do it on the same grinding stone as I sharpen my lathe cutting tools on. For this purpose, a fairly rough grind is OK as long as it is round.
 
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Talltim

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I do all my turning between centers using a 60 degree live center in the tailstock and a small, parallel sided center in my headstock chuck. . This latter piece I made myself. . And I made one for each of the different pen

Despite your description I am having a bit of a difficulty visualizing your parallel side center in your headstock.

How about a picture of one?
 

JimB

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I do all my turning between centers using a 60 degree live center in the tailstock and a small, parallel sided center in my headstock chuck. . This latter piece I made myself. . And I made one for each of the different pen

Despite your description I am having a bit of a difficulty visualizing your parallel side center in your headstock.

How about a picture of one?
It's parallel rather than being a Morse taper because it is going into his chuck not directly into his headstock.
 

Woodchipper

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I have dial calipers. Slim Line pens are impossible to disassemble I am told. I have already done three sets of blanks for one pen! If this keeps up, I'm going to take up needlepoint.
 

Woodchipper

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I don't know whether I'm going to do that as I have more time invested than I care to count. I just drilled ANOTHER acrylic blank- one piece came out OK, t h e other had a hole so big you could throw a through it.
I'm going to see if my pens sell that I gave to a friend. If not, then I will be having a big sale on slightly used stuff.
Thanks.
 

leehljp

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flyitfast

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Look at Brian Nikitas. He makes TBC bushings for most of the common pen kits. I have the 7mm (slimline) bushings and they work great.
Gordon


Measure the components and turn to that size, use the bushings as a get close guide. Does anyone make turn between center bushings for a slimline?
 

Woodchipper

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What I was thinking of was the disclaimer that the kit didn't work with pencils. I have a set of punches and have used them already. I'll be in Chattanooga this weekend for Turning for the Troops. I'll see if WC has it in stock. I just hate to start all over with all the time I have spent so far on just four pens. C'est la vie! Thanks to all for your replies.
FWIW, I received a PM from a member offering to give me some help with the skew and synthetics.
 

gtriever

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I've managed to get most of my mistakes apart without damaging them using the HF punch set, along with a pair of disassembly pliers and the HF arbor press. The key for me is to use the ram on the press like a hammer, giving the punch short taps rather than steady pressure.

Re your original question, sandpaper is my friend. I turn as close as I'm comfortable with, then go to the sandpaper. Lots more work... but it works while I get more experience in turning close to the bushings.
 

Woodchipper

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I find that I can get very close with sandpaper and wood but synthetics are a different story. I just squared two blanks for my sister-in-law's pen- the third try. I have the dial calipers out and will check the spec's on the bushing chart on this site.
 

JimB

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I'm not sure why you need to compare anything to the bushing chart on the site. Measure your bushings and measure your kit. That will tell you if they are a good match and what you need to do to get a good fit.
 

Woodchipper

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Bringing this to the top. I went to the local Woodcraft store for Turning for Troops. One of the employees, Mike, showed me how to use the transfer punches to disassemble a Slim Line pen. So easy a nine year old could do it but I don't know any nine year old kids. Going to give it a try tomorrow or Monday. I need to design something to hold a pen blank while tapping to push out the parts. Any ideas? Again, thanks to all for their replies, advice, sympathy, etc.
 

duncsuss

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I need to design something to hold a pen blank while tapping to push out the parts. Any ideas?
Rubbermaid dish-washing glove. It gives you just the right amount of grip, not so much that you are tempted to whack the transfer punch with all your might, but enough to keep the pen barrel from slipping out of your fist.

In my experience, many fast light taps with a mallet works better than a single hard blow.
 

Woodchipper

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In my experience, many fast light taps with a mallet works better than a single hard blow.
You know the old saying- Don't force it, use a bigger hammer.
Thanks for the tip. PSI makes a vise grip with coated jaws much like a welder's clamp. Got a couple of ideas for something a bit more permanent.
 

Talltim

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When you are taking a pen apart with punches, I have learned from experience (sorrowful experience I might add) to always do it over a spread out towel or something soft. It can save a dent or scratch in a nib, barrel, or other part if it comes apart more zealously than anticipated.
 
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JimB

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I also use the dishwashing gloves for grip and transfer punches. I series of light taps does the trick. You don't need to buy or make anything fancy... unless you like doing that.
 
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