Which bushing?

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JustLookin'

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I've been making specialized "Stylus" type pens for almost a year. We don't drill all the way through the blank, only about a half inch into each end.
I've not been using bushings, just tightening it between the dead and live centers, which works well....most of the time. I still get the odd one that has an off center on one end (even though drilled dead center), which makes my tapers look off.
I'm hoping the attached picture shows what I mean.

I've just been looking into using bushings, as I think these will be a game changer, but I don't know what ones I need, as I am not using a pen kit for these.

We drill with a 5mm drill bit, so can someone let me know what size bushings I'd need?

If there is nothing this size available, what would be the easiest way to make something suitable? I have a metal lathe also, so could possibly turn something, but would need a bit of advice please.

1582027552537.png


Thanks heaps
Lynne
 
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elyk864

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I don't think you're going to find bushings to make what you need. I think all standard pen bushings are made to go on a 7mm mandrel so that already is way larger than what you need. Time to hit the metal lathe lol.
 

ed4copies

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You CAN make bushings out of corian on your wood lathe. Fairly simple and should work for the dimensions you need (corian is usually half an inch thick).
 

darrin1200

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I’ve made a few custom bushings like this for turning between center.
Forgive the rough sketch. You can do this on your metal lathe. I just use some scrap steel rod I have on hand. With your rod in the headstock, use a 60deg center drill in the end. You don’t have to go very deep, just enough to get good surface contact to your live center.. This is used for turning between centers, as well as offering support while making the bushing.

Turn the shape shown. The 5mm piece should be the length needed to get close to the bottom of the hole drilled in your blank. The middle section (finish) is turned to your final preferred dimension for your blank and should be long enough to give you some clearance. I would only go about 5mm. The largest dimension needs to be enough to give you some clearance around the 60deg hole.
Hope this helps.
D9F81187-7689-4868-8541-5B2D9181DAAC.jpeg
 

darrin1200

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As a note, I make a number of these for turning between center when I am using 7mm tubing( gives better support). Or when I am using brass tube pieces that do not go all the way through the blank.
 

magpens

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I don't understand why you are having any problem doing it the way you have been ......

***** ..... unless the ends of the blank you are turning are not square with the axis of the blank. *****

Looking at your picture, that could very well be the problem .... the top end seems to be slightly sloping down to the left.

The ends need to be perpendicular (square) to the axis of the blank in order to get accuracy with Turning-Between-Centers.

You will get the same problem when using bushings if you hold THEM between your centers without a mandrel ....

.... your blank must have square ends !!!
 

greenacres2

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I'm with Mal on this--looks like it didn't start square. Another possibility might be slop in the tail stock before locking down. My Rikon has a little play in tail stock when loose--and i have to remember to apply a little pressure to the front of it as i'm locking down or i don't line up center. Not much off--but enough to cause a bit of off-center look. Rick Harrell's tail stock clamp may help that...i'll know in a few days since he's just mailed it today!!
earl
 

JustLookin'

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I don't understand why you are having any problem doing it the way you have been ......

I have been at a loss about this also, so while looking for information, I saw some people using bushings, and figured this might be the reason

***** ..... unless the ends of the blank you are turning are not square with the axis of the blank. *****

I think you might be right on the money here. This blank is one I poured, and I didn't square it up, but I have this problem with bought blanks also.....guessing they aren't being squared up either.

So what's the easiest way to do this?
 

magpens

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@JustLookin'

DO NOT rely on any blank (even if purchased) to have "squared" ends.

The best way to square up the ends of your blanks ....
I believe you have a metal-working lathe. . Hopefully the "throat" of this lathe is large enough (about 0.75" diam or a little larger is a standard size for the bench-top mini lathes) that you can put your blank right into the headstock chuck (and hold it with the jaws) so that there is only about 1 inch or less sticking out (if it is more than one inch, it should still be OK, as long as the blank is gripped securely in the head stock chuck and as long as your turning speed is not too high.). . Then spin the blank at fairly low speed and carefully watch the end face that is sticking out. . If this end face gives the appearance that it is "wobbling" even slightly, then you definitely have to square it up.

[This next paragrah is a side note but definitely worth reading ....
To do the squaring up, your blank should first be rounded. . If your blank is not rounded you should do that by mounting it between centers and turning it round. . Just a cautionary note here ... your rounding will be only approximate if the blank ends are not already "squared", but at this stage, the approximation will be good enough ... just remember that you can't rely on the center holes (used for mounting between centers) at this time to remain accurate and once you have done the rounding you should redrill them ... using the lathe to do the drilling. . If you don't understand what I am getting at, then please ask me to explain more fully. ]

[Continuing the main discussion, after skipping/or having read the paragraph immediately above ....]
You can do that squaring by putting a cutting tool in the tool holder (on the cross feed) and slowly move it to a position against the end face, at which point a little bit of material will be cut off. . Then turn the cross feed to cut off material from the face. . Move the cutter a little further into the end face, and repeat the cut (using the cross feed knob). . Don't take off very much with each cut. . Keep doing this until the end face is "squared" and does not appear to "wobble" any more. . When you have reached that point, the end face will be "squared", or perpendicular to the blank axis.

(if any of this is not clear, be sure to ask me to clarify)

BTW ... where in Australia do you live ? . I worked in Adelaide from '69 til '82. . Three of my four sons were born there. . We absolutely loved our time there and I often regret leaving. . But our extended families are all here in Canada so it was inevitable that we would come back and allow the boys to get to know their cousins, grandparents, etc. . We have had a couple of trips back, but none since '93, and the 4 boys all have grown up kids of their own now.

Cheers,
Mal
 
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JustLookin'

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ok, so first of all, it may help if I explain roughly how we do our pens.

We start with a pilot hole, about 3mm deep, maybe a touch more, which is drilled on the wood lathe (each end). Then the blank is put on to the metal lathe and turned down to the diameter we need.
Once that's done, it goes back on the wood lathe to have the ends tapered, sanded and finished. After this, the ends get drilled to the depth, again on the wood lathe (I need another machine LOL).

Now, reading your side note, you are saying that the blank should be rounded to get the squaring right, so would doing it how we are work. Could we add the squaring up part in there before the "tapering" part?

I'm going to have to see what I can rig up to do the cutting/sanding, but I have a pretty good idea of what you are saying.

I actually live in South Australia. Virginia, which is north west
 

darrin1200

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ok, so first of all, it may help if I explain roughly how we do our pens.

We start with a pilot hole, about 3mm deep, maybe a touch more, which is drilled on the wood lathe (each end). Then the blank is put on to the metal lathe and turned down to the diameter we need.
Once that's done, it goes back on the wood lathe to have the ends tapered, sanded and finished. After this, the ends get drilled to the depth, again on the wood lathe (I need another machine LOL).

Now, reading your side note, you are saying that the blank should be rounded to get the squaring right, so would doing it how we are work. Could we add the squaring up part in there before the "tapering" part?

I'm going to have to see what I can rig up to do the cutting/sanding, but I have a pretty good idea of what you are saying.

I actually live in South Australia. Virginia, which is north west

If I understand your workflow, then your are turning between centers on the metal lathe. I do the same thing using a steb center in the headstock. If you are doing the same,

  1. First cut the blank about a few millimetres longer than need
  2. Then I would use an awl or other sharp point to mark the centres rather than drilling them.
  3. Turn the blank round on your metal lathe.
  4. Then mount the rounded blank in a 3-jaw chuck (personally, I use an ER32 collet chuck) and use your cross slide to trim the end off, removing the previously used centre mark.
  5. Next, while it is still in the chuck, drill your 5mm hole.
  6. Finally, turn it around in the chuck, to square the other end and trim it to final length.

Now you can move it to your wood lathe to taper the ends and polish. Personally, I would still make a couple of between center bushings, to prevent the ends from splaying if to much pressure is applied.
 

magpens

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@JustLookin'

What you are doing sounds fine. . But, yes, I would do the squaring right after rounding and before the tapering.
You can do the tapering on the metal lathe ... that could be more accurate to get the angle right, if that is critical. Sanding to remove "corner".

See the lathe's angle scale, just above the knob for the cross feed.
The cross slide should enable you to set the angle you want, but that is a fairly rough setting, and a digital protractor gives much better accuracy.
To change the angle, you first have to back out the cross feed nearly all the way. . That should reveal two Allen head set screws with heads up.
Loosen those set screws and the top part of the cross feed should rotate to the desired angle. . Then tighten the set screws again.

If you could please post a photo of your metal lathe (close up of the cross slide) that would greatly help in giving you proper advice.
 

leehljp

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Agree with Mal 200%.

Repeating what has been said several times, SQUARE the blank before putting it onto the dead center to turn. IF it is NOT squared, the offset of the blank end will affect how it aligns, hence - the problem.

BTW, even bushings purchased or made will not correct the problem if the ends are not squared. Bushings may helps "some" but the problem will still be there.
 

JustLookin'

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If I understand your workflow, then your are turning between centers on the metal lathe. I do the same thing using a steb center in the headstock. If you are doing the same,

  1. First cut the blank about a few millimetres longer than need
  2. Then I would use an awl or other sharp point to mark the centres rather than drilling them.
  3. Turn the blank round on your metal lathe.
  4. Then mount the rounded blank in a 3-jaw chuck (personally, I use an ER32 collet chuck) and use your cross slide to trim the end off, removing the previously used centre mark.
  5. Next, while it is still in the chuck, drill your 5mm hole.
  6. Finally, turn it around in the chuck, to square the other end and trim it to final length.

Now you can move it to your wood lathe to taper the ends and polish. Personally, I would still make a couple of between center bushings, to prevent the ends from splaying if to much pressure is applied.

Never thought of using an awl to mark holes in the centers first. Would I actually make a hole, or just mark it? I'll give that a try next time I go out to turn.

The metal lathe is primarily set up just to turn the blanks to size. Hubby doesn't like to play with changing anything on it now we have it setup correctly, as it's a huge PITA to get it back to where we need it to be.
With this in mind, I need to work out how to square the blanks on the wood lathe, as it is so much easier to switch things out and change them on that one (I do it all the time).
We have this pin chuck on our wood lathe, which holds the blanks in place very well, before and after turning.
1582179750945.png

These are the ends we use, both on the metal lathe and wood lathe for TBC
1582180033968.png
1582180095792.png

We tried the steb center, but it did not work as well as we needed.
 

JustLookin'

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@JustLookin'

What you are doing sounds fine. . But, yes, I would do the squaring right after rounding and before the tapering.
You can do the tapering on the metal lathe ... that could be more accurate to get the angle right, if that is critical. Sanding to remove "corner".

See the lathe's angle scale, just above the knob for the cross feed.
The cross slide should enable you to set the angle you want, but that is a fairly rough setting, and a digital protractor gives much better accuracy.
To change the angle, you first have to back out the cross feed nearly all the way. . That should reveal two Allen head set screws with heads up.
Loosen those set screws and the top part of the cross feed should rotate to the desired angle. . Then tighten the set screws again.

If you could please post a photo of your metal lathe (close up of the cross slide) that would greatly help in giving you proper advice.

Our metal lathe is what they call a mini metal lathe. It's adequate for what we are doing, but it's a right PITA to change it once it's setup.
We tried doing the tapers on it (failed), and it took us hours to get it set up to cut straight again :( We then decided to just have it setup to turn the blanks round, and everything else can be done on the wood lathe
 

magpens

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@JustLookin'

I'll just chirp in a short one here regarding this statement of yours:

"Never thought of using an awl to mark holes in the centers first. Would I actually make a hole, or just mark it? I'll give that a try next time I go out to turn."

I use an awl to make a small, but significant, mark where I have determined the center of the blank end to be .
I then use a battery operated hand drill with a 1/16" drill bit to drill a hole (about 3/16" deep) at the awl mark.
With that small hole at both ends, the blank holds quite well for TBC (Turning Between Centers).
The awl mark is deep enough that the 1/16" drill bit does not wander at the start of drilling while I am holding both the blank and drill by hand.
Note that this is not the main drilling operation, which is our ultimate major concern when making a pen.

And then, you might ask, how do I determine where the "center of the blank end" is.
To do this, I use a 45 degree "square" ... a small machinist square that actually fits over the "nearly square" corners of the blank.
I scribe (with an Exacto knife) 4 diagonal lines on the end of the blank, one based on each corner.
Those 4 scribe lines will not exactly cross, but they come close enough that I can then make the awl indentation at very close to center.
A "good" tool store should be able to supply the 45 degree square ... it is of fixed construction, not adjustable in any way ... price about $10.00
It is a very handy gadget that I use on every blank that I am planning to turn.

If you don't want to buy the 45 degree square, then you can just eyeball the center and make your awl indent (quite forcefully).
Hitting the exact center at this stage is not super critical. . But it is important to stick with whatever "center point" you start with.

This all assumes that the end of the blank has been "approx. squared up" beforehand. . That can be tricky to do before the blank is rounded.
So it is OK to do the rounding based on "approximately squared up" blank ends (perhaps using a belt sander or disc sander).
You can then do the accurate "squaring up" immediately after rounding the blank, but before you do any real hole drilling into the ends, the hole drilling being done on the lathe.

I hope my meaning is clear enough .... it is getting very late here, and I may not be communicating well.
 

More4dan

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Here is another slightly different way that I use to turn round and square the ends. I take a 60 degree center drill and put a small dimple on each end of the blank. I then mount the blank between centers and turn it round. Now cut it a bit longer than needed. I then sand then ends square using a fence set at 90 degrees on either my disc or belt sander.

Now you can mount in the chuck and drill your ends. I always start with a center drill.

When using brass tubes I will drill and glue in the tubes before squaring and just sand to the tubes.

Using the adjusted compound slide on the metal lathe will only give a straight taper to the end.

Danny


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darrin1200

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Never thought of using an awl to mark holes in the centers first. Would I actually make a hole, or just mark it? I'll give that a try next time I go out to turn.

The metal lathe is primarily set up just to turn the blanks to size. Hubby doesn't like to play with changing anything on it now we have it setup correctly, as it's a huge PITA to get it back to where we need it to be.
With this in mind, I need to work out how to square the blanks on the wood lathe, as it is so much easier to switch things out and change them on that one (I do it all the time).
We have this pin chuck on our wood lathe, which holds the blanks in place very well, before and after turning.
View attachment 233431
These are the ends we use, both on the metal lathe and wood lathe for TBC
View attachment 233432View attachment 233433
We tried the steb center, but it did not work as well as we needed.


For simple straight turning and facing, there should not be significant change to your set up, other than the cutting tool. This is why a quick change tool post is a very worthwhile investment.

The mark is just there to catch the tip of your centre. The steb centre is of no use once the blank is drilled, but it is great when the blank is solid. It holds much firmer against the cutting action. Once the holes in the ends are drilled, that is when I would switch to the dead centre in the headstock, as then the steb centre is basically useless.

You really need to learn to do multiple operations on your metal lathe, to really gain its advantage. I have a pocket pen I make, that I make in bulk. Almost every step, from rounding the square blank to the final size trimming, is done on the metal lathe. (I do the polishing on my wood lathe because of machine speed). I do all the pens one step at a time. That way I am only changing the lathe to each step once. I even went through and documented each step of the process, with a literal checklist of each tool change, dial change, and depth adjustment. For a manufacturing process like you guys are using, this can make a significant time savings.
 
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