Irritated with bushings

Signed-In Members Don't See This Ad

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
70
Location
NY
I just finished up several pens today that I'm not happy with because the wooden barrel is a little proud of the metal pen fittings, enough to be noticeable when you run your finger across the pen. I'm pretty new to this but I've turned a number of different style pens so far and this is the first time I've seen this to this extent. The pen kit is from PSI and I used the recommended bushing set and was very careful to turn and sand the wood all the way down to bushing level (one of them was turned a few thou below the bushing and still is too big when the pen is assembled). I'm not sure how to fix the problem at this point since the pens are assembled and I haven't been too successful with getting assembled pens apart without ruining the nice metal bits.

I think (from reading here) I know the answer to the sizing problem: learn to turn between centers and use a digital caliper to make sure the blank is turned to the correct size. I have the equipment, just have to learn and start doing it.

One other thought/question: how do you experienced pen makers account for the thickness of the finish (I use usually 15 coats of thin CA), or do you even need to do that?
 
Signed-In Members Don't See This Ad

acmaclaren

Angi the Maker
Joined
Oct 28, 2012
Messages
241
Location
Seattle WA
I mostly turn PSI kits. I've never had a problem with you're talking about. You could have a bad pair of bushings or a bad kit. You could also have the wrong bushings. I had bought some bushings for the ballpoint version of a kit, but received the roller ball version instead. When I went to do my usual test fit of brass tube and bushing is when I discovered the problem. The bag was labelled correctly, but the bushings in the bag were wrong. I called PSI and they sent out a correct set of bushings. You may want to call PSI and talk to them about your problem.
 

Pierre---

Member
Joined
Jun 10, 2012
Messages
159
Location
France
Sanding is not good for bushings, and sometimes the fittings OD is different from pen to pen, even from the same order. So you do need a caliper, bushings are only an indication, nothing else.

I turn .1mm under, then apply CA which make it .1mm over, sand it and make it shine, and correct OD is reached. Sometimes it works...
 

magpens

Member
Joined
Feb 2, 2011
Messages
10,415
Location
Coquitlam, BC, Canada
"One other thought/question: how do you experienced pen makers account for the thickness of the finish (I use usually 15 coats of thin CA), or do you even need to do that? "
You definitely need to take the thickness of the CA into account.

However, your question is really tough to answer. . So much depends on your personal technique for applying and smoothing the CA, and it also depends on your sanding of the CA.

What's more, it depends on the brand of CA and what "they" call thin/medium/thick. . On top of that, it depends on the age of the thin CA, if that is what you are using. . I have found that as thin CA ages in the bottle (I am talking a matter of 3 to 4 months or so) it tends to thicken.

For me, I usually count on my application of CA to result in a radial size increase of about one thou and I undersize my turning by that amount.
And as for number of coats, I would rarely use more than 4 to 6 coats, and often it is only 3 coats. . I tend to sand lightly between coats in order to avoid heavy sanding at the end of CA application, when you can have significant "hills and valleys" on the CA surface .... again, depending on your technique.

As Pierre said above ... "Sometimes it works ..." !!

However, I have to disagree strongly with Pierre's estimate of the allowance for CA thickness ... his "0.1mm" amounts to about 4 thou ( 0.004" ) and that is a really enormous thickness allowance/correction for a CA finish !!! .... 1 mm = 0.03937" or ~40 thou
 
Last edited:

ed4copies

Local Chapter Manager
Joined
Mar 25, 2005
Messages
23,707
Location
Racine, WI, USA.
If you have a digital caliper and you are "anal" about your measurements, make your own bushings.

Measure the fitting you are going to be matching and turn a piece of corian or some other fairly dimensionally stable material to the size you will need.
 

Mortalis

Member
Joined
Aug 19, 2013
Messages
291
Location
Rochester, Mass
Something else that an old timer told me some time ago was to check your bushings to the kit and once you have the barrel(s) to the desired diameter, turning between centers, remove the bushings and ever so slightly round the edges over before applying your coating. This will keep the sharp corner from revealing itself if a slight difference occurs between the diameter of the barrel and the kit part(s). It doesnt take a lot. Most times just enough to break the edge.
 

Dehn0045

Member
Joined
Mar 19, 2017
Messages
974
Location
Houston, Texas
I usually shoot for about 0.003 to 0.005 final CA thickness. I build-up about 0.001 to 0.002 extra for sanding/polishing. I find the amount thickness added per coat is highly dependent on method (specifics), for example I get about 0.001 per coat of thin when I use a foam applicator, but when I use paper towels it might take 4 coats to get the same amount.
 

jttheclockman

Member
Joined
Feb 22, 2005
Messages
12,649
Location
NJ, USA.
There is nothing wrong with turning with bushings. I do it all the time. But what I always do before I turn a blank I use calipers to measure the kit parts and write those down. I then measure the bushings and this tells me how close they are to kit parts. Remember the plating on all kits is not always the same and this can vary. Each batch the manufacturer runs could be different. I now turn the blank having this knowledge at hand. If acrylic no need to worry about over turning to allow for CA. After awhile you get a feel for how far you need to turn past the bushings to allow for the amount of CA you use. Thin takes more coats than combination thin and med CA. Now if i need to overturn a blank then I take off the bushings and turn that small amount between centers. It is no big deal because I always sand or polish between centers any way. This all becomes second hand stuff after you do a few. You will see. One thing I do that I find has helped me greatly over the years is turn one blank at a time and not put both blanks on the mandrel. It shortens the mandrel and takes out the whipping action that can happen. Always let the tool do the work and sharp tools is a key.
 

leehljp

Member Liaison
Joined
Feb 6, 2005
Messages
6,855
Location
Tunica, MS,
First of All: There are about half a dozen things that can go wrong with a mandrel in which TBC eliminates. When TBC started on this forum, newbies came on and repeatedly said "such and such" Company "said", or "have" or "Recommend" or "Sell" . . .
. . . and the mind set is: since the large companies sell x, y, z,, then it must be true.

Fact is, it can be, but one has to be experienced for it to fulfill the "can be" as touted by the large companies. When I started, everyone used mandrels and the very experienced ones knew how to compensate for bushing sizes that didn't match the fittings exactly; they knew how to compensate for what caused mandrel flex; They knew their lathe and its characteristics.

The assumption of mandrels being perfect or bushings being precise is absolutely wrong. This is a "mindset" problem. There is nothing wrong with using mandrels and bushings, but don't put your 100% trust in those just because the big companies sell them. The big company and small company attachments are good, but they require experience to know when to compensate for the imperfections that creep in. Again, this is a "mindset" problem. If you did not know that bushings are not perfect (unless buying custom machined ones at 2 to 4 times the cost of mass produced ones), it means that you trusted to manufacturer to or product to be precise to 1/1000th inch or better and they are not.

You are doing excellent in that you have begun to recognize that there are imperfections in the mass produced accessories; You will still need them but now learn to compensate for the imperfections in different ways. Use calipers for the standard of measurement; Use TBC when possible; Plan for, use and measure the thickness of CA for the final fit. I turn down blanks to about .005 or .008 below the size and build up to about +.005 larger and sand or turn down to the same size as the fitting. The extra time for this kind of precision is about 5 to 10 more minutes per pen on average, and to me well worth it.

BTW, there are two kinds of measuring devices: calipers and micrometers:
(Get METAL ones, not composite ones.) These are accurate to .005

And Micrometers"
accuracy to .0001
I have begun to use this more and more as I try to get measurements to .001
 
Last edited:

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
70
Location
NY
Lots of GREAT suggestions and information here, thanks everyone for sharing your ideas! I'm sure I'll have more questions as I learn how to TBC and start using the digital calipers routinely. I have turned some blanks round by TBC but have been a little afraid to take them down further because I'm afraid of gouging or rounding the ends; just need to practice some more probably; I also need to get over the mindset that its not the end of the world if I mess up a blank; most blanks are cheap, and so are brass tubes. I picked up an old analog micrometer from a garage sale recently, I'll have to check to see what the level of precision is, but I suspect another trip to Harbor Freight is in my future.
 

magpens

Member
Joined
Feb 2, 2011
Messages
10,415
Location
Coquitlam, BC, Canada
@FGarbrecht

You mentioned getting the analog micrometer ... you will find that useful, but you will quickly tire of using it for pens.

A digital caliper should definitely be in your future. . And as Hank said above, don't get the "composite" (ie. "plastic") one .... get the metal one.

With the metal digital caliper, you can count on making measurements to an accuracy of better than 0.001".

With the "composite" caliper, your accuracy can downgrade to as poor as 0.005", as Hank said, and that is not good enough for pen-making.

Every pen-maker should be alert to manufacturers and vendors pushing the mandrel and bushing concepts onto us.
Those things are additional revenue for them ! . And just think of all the disadvantages of bushings !!

The direction for everybody who loves making pens should be towards Turning Between Centers, and learning to use calipers.
In my opinion, that is the true source of excellence and satisfaction.
 

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
70
Location
NY
@FGarbrecht

You mentioned getting the analog micrometer ... you will find that useful, but you will quickly tire of using it for pens.

A digital caliper should definitely be in your future. . And as Hank said above, don't get the "composite" (ie. "plastic") one .... get the metal one.

With the metal digital caliper, you can count on making measurements to an accuracy of better than 0.001".

With the "composite" caliper, your accuracy can downgrade to as poor as 0.005", as Hank said, and that is not good enough for pen-making.

Every pen-maker should be alert to manufacturers and vendors pushing the mandrel and bushing concepts onto us.
Those things are additional revenue for them ! . And just think of all the disadvantages of bushings !!

The direction for everybody who loves making pens should be towards Turning Between Centers, and learning to use calipers.
In my opinion, that is the true source of excellence and satisfaction.
I have a metal digital caliper but I'm about to head out to pick up a digital micrometer. I'm sure the analog micrometer will get old quickly.
 

larryc

Member
Joined
Oct 2, 2009
Messages
1,110
Location
Mableton, GA (Near Atlanta)
As stated many times, make your turning match the pen parts not the bushings. The best way to do this (and the easiest) is with the Sierra type pens where you can use the nib section that just slides into the tube. You'll find that you can be several thousandths off and not be able to feel the difference between the turned blank and the component. And "feel" is the operative word here. When you get to the point that you have extra component parts for other pens (especially nibs) you can place them between centers and file down the press fitting so it just fits in the tube. Then use this as your final analysis of the blank to component fit.
 

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
70
Location
NY
If you are turning between centers, is there any reason to mess with bushings at all, as long as you are going to the effort of meticulously measuring with a digital micrometer? When I try to turn down slightly below the level of the bushings I seem to get dark metal staining of the pen blank ends from my tools hitting the bushings. It seems like it would be reasonable to put the bushings on during the rough turning down to close to the level of the bushings (to help take off material really quickly without worrying too much about the size), and then take the bushings off for finish turning and sanding at which point you start measuring like crazy to finished size. Does this make sense?
 

magpens

Member
Joined
Feb 2, 2011
Messages
10,415
Location
Coquitlam, BC, Canada
@FGarbrecht

What you have stated immediately above makes perfect sense !!! . If you insist on buying bushings, that's the way to use them.

But you don't need them at all really. . You quickly get a feeling for (or an eye for) how far to go before you start your measuring.

Let me also state my preference for caliper over micrometer.

You can use your caliper with one hand ... blank to be measured in left hand, caliper in right (assuming you are right-handed).

But to even hold a micrometer in the measuring position, you need two hands. . Your blank has to then be held in a vise, or something else !!!

Some skilled machinists can use a micrometer to measure small parts, or shim thickness, holding & operating the micrometer with only one hand.
But that is a fairly advanced skill, in my opinion.
Usually with a micrometer, the yoke-shaped part has to be held from moving with one, while you adjust the actual measuring anvil with the other.
I find it hard to do that when measuring something the size of a pen blank.
Of course, I am assuming that you take the blank off the lathe to do the measurement .... you may not have to .... but I find that's the only way I can get sufficient accuracy when measuring with calipers. . I haven't tried seriously with a micrometer.

The trouble with trying to make your diameter measurement while the blank is still on the lathe is that it is hard to be sure that your measuring instrument (caliper, micrometer) is actually positioned precisely at right angles to the axis of the blank. . By holding the blank in one hand and measuring with the other, you just kind of get a much better feel for an accurate measuring process. . Things are all the harder if your blank surface is not a precise cylindrical surface. . In making a pen, you often want to bulge-out the surface a slight amount. . It is much easier to make an accurate measurement with the blank in your hand. . I might add, also, that it is much easier to do this with calipers, which have thin jaws, rather than a micrometer, which has "anvils" which are, perhaps a quarter-inch thick. . The anvils work best for measuring things with parallel sides, such as sheet metal thickness.
 
Last edited:

Woodchipper

Member
Joined
Mar 15, 2017
Messages
2,686
Location
Cleveland, TN
I got the dark ring from the bushings. That's why I'm trying TBC. As mentioned, measuring the components to match the blank diameter.
Have four pens to turn and will report in another thread.
 

Woodchipper

Member
Joined
Mar 15, 2017
Messages
2,686
Location
Cleveland, TN
I usually shoot for about 0.003 to 0.005 final CA thickness. I build-up about 0.001 to 0.002 extra for sanding/polishing. I find the amount thickness added per coat is highly dependent on method (specifics), for example I get about 0.001 per coat of thin when I use a foam applicator, but when I use paper towels it might take 4 coats to get the same amount.
Interesting. Craft foam to apply CA? Size? Can get tons at Hobby Lobby. I use paper towels but your post tells me I'm maybe wasting some. We know CA isn't cheap...like me.
 

leehljp

Member Liaison
Joined
Feb 6, 2005
Messages
6,855
Location
Tunica, MS,
If you are turning between centers, is there any reason to mess with bushings at all, as long as you are going to the effort of meticulously measuring with a digital micrometer? When I try to turn down slightly below the level of the bushings I seem to get dark metal staining of the pen blank ends from my tools hitting the bushings. It seems like it would be reasonable to put the bushings on during the rough turning down to close to the level of the bushings (to help take off material really quickly without worrying too much about the size), and then take the bushings off for finish turning and sanding at which point you start measuring like crazy to finished size. Does this make sense?
The dark metal staining IS the bushing dust, as you have discovered. Bushing dust means the bushing is getting smaller ;) due to sandpaper, or the chisel nudging the bushings, therefore rendering them inaccurate for sizing. One of our early on IAP members considered bushings as "consumables", i.e. they MUST be replaced on a regular basis. Now, with TBC, they don't have to be replaced as they are not used for "sizing" but to hold the blank for a short period of time.

. . . " is there any reason to mess with bushings at all?" Depends. Some people are experienced enough to eliminate the bushing all together. I use the bushings on TBC to get the blank to near size. In a matter of less than 10 seconds, I can have the bushings out and the blank turning without bushings. The problem that most people have - with not using bushing to get started - is that the blank will slip, OR, they will tighten the tail stock too much and flare the brass tubing. I have flared it enough times and so I use bushings to get it round and down to near size; three turn down to size, checking with digital calipers or micrometer.
 

magpens

Member
Joined
Feb 2, 2011
Messages
10,415
Location
Coquitlam, BC, Canada
I don't see how the brass tubing can flare if it is glued inside the blank.

... perhaps an eentsy-teentsy bit (couple of thou) of distortion/expansion at the very ends over a length of a few thou but that won't matter when you press in the hardware.
 
Last edited:

Dehn0045

Member
Joined
Mar 19, 2017
Messages
974
Location
Houston, Texas
Interesting. Craft foam to apply CA? Size? Can get tons at Hobby Lobby. I use paper towels but your post tells me I'm maybe wasting some. We know CA isn't cheap...like me.
I actually use open cell polyurethane foam like this (https://www.hobbylobby.com/Fabric-Sewing/Batting-Fillings-Forms/Cushions-Pillow-Forms/Poly-Foam-Pad---1"-x-14"-x-14"/p/36738). I cut it into 1/2" x 1" x 1" and can usually get 4 applications with each piece. I apply the CA to the blank spinning at 500rpm and use the foam to smooth it out. I use BSI thin. You do need to use a little caution with accelerator when you have a thick layer of uncured thin CA on the blank, it can haze up easier than the paper towel method. The open cell foam soaks up a little CA, but I like the additional working time and if I get too aggressive with the CA the foam will soak up the excess so it takes a little less skill.
 

jttheclockman

Member
Joined
Feb 22, 2005
Messages
12,649
Location
NJ, USA.
I don't see how the brass tubing can flare if it is glued inside the blank.

... perhaps an eentsy-teentsy bit (couple of thou) of distortion/expansion at the very ends over a length of a few thou but that won't matter when you press in the hardware.
Absolutely. When you turn between centers and use a live and dead center it most certainly can flare to the point that components will fall out. When you only use that method from start to finish you put much more pressure on the blank at the start to keep from spinning and when it does this too flares the inside of the tube just like reaming. Using between bushing is a way to go but they are expensive. When you drill and install the tube. That tube is never dead center of a hole. It can lean one way or other and when pressure is applied it can dislodge it or can oblong it again because you need to apply more pressure at the start. It takes a touch to be be able to turn without bushings. Lets remember we have newbies asking these questions so give all facts. As I said i always start with the bushings designed for the kit and they are just fine. When I get close I may change to between center turning. Even if you undercut the bushings do not throw them away. They are still usable. Just keep a measurement of what the size they are compared to the components.
 

Woodchipper

Member
Joined
Mar 15, 2017
Messages
2,686
Location
Cleveland, TN
I actually use open cell polyurethane foam like this (https://www.hobbylobby.com/Fabric-Sewing/Batting-Fillings-Forms/Cushions-Pillow-Forms/Poly-Foam-Pad---1"-x-14"-x-14"/p/36738). I cut it into 1/2" x 1" x 1" and can usually get 4 applications with each piece. I apply the CA to the blank spinning at 500rpm and use the foam to smooth it out. I use BSI thin. You do need to use a little caution with accelerator when you have a thick layer of uncured thin CA on the blank, it can haze up easier than the paper towel method. The open cell foam soaks up a little CA, but I like the additional working time and if I get too aggressive with the CA the foam will soak up the excess so it takes a little less skill.
Thanks. HL is about two miles from here. Wife and I stop when we go by just to look. She looks at fabrics and I just look. Copied SKU to my phone. Wife might already have some, will check with her.
 

pshrynk

Member
Joined
Dec 6, 2017
Messages
305
Location
Lake City, Minnesota
One consideration might be that there is an upper and lower end to the blank, with the nib end being slighlty smaller. If you don't get that right, then there will be a step off on either end. DAMHIKT.
 

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
70
Location
NY
One consideration might be that there is an upper and lower end to the blank, with the nib end being slighlty smaller. If you don't get that right, then there will be a step off on either end. DAMHIKT.
Fortunately the Sierra kit has the same diameter at each end. I'm about to advance my skills by trying my hand at some more contoured pens with different end measurements, so good reminder to be careful.
 

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
70
Location
NY
Trying another experiment. I just designed a Sierra bushing set in Fusion360 and am printing up a set on my resin printer. Precision probably does not come close to compare to a machine shop metal bushing, but it will be interesting to see if they are concentric enough to allow me to do rough turning to size on a pen mandrel. My hopes are not too high for this experiment, but if it works it would be nice since print time is quick and the cost is just pennies.
 
Top Bottom