Bushings and their interchangeability

[RussFairfield]

The question is often asked whether one manufacturers bushings can be used on another's pen. The real problem is finding a set of bushings that are the correct size. It seems that there is no dimensional control of their diameters, and no manufacturer is any better than the others.

An example is the 7mm Slim-Line pen. The diameter of the pen fitting at the tip is a constant 0.329" to 0.330" for all manufacturers. I have no idea what the target bushing diameter should be, but the ones I have measured vary between 0.321" to 0.346". And then we wonder why everyone has a problem with getting a good fit between the wood and the fittings. If we get a set that is right, and they are all the same within the set, we can consider ourselves lucky. I haven't found the bushings for the other kits to be any better.

Some have solved this dimensional problem by making their own bushings. I solved it by not using the bushings for a diameter control of the wood, and turn to a diameter as measured with a dial caliper.

 

[Fangar]

Russ raises a good point (For once... Geeze []). I use a digital caliper and only use the bushings as a reference. The unfortunate thing is machine tolerances in bushings. I have had bushings off by as much as almost 3 thousanths. I have machinist friends who constantly have to work at maintaining precise tolerances. There is no set it an forget it. Bruce Boone will likely attest to this having experienced it in his line of precise work.

Fangar

 

[its_virgil]

I, too, learned early on that bushings were mostly to hold the tubes and blanks and to turn with calipers close by. Bushings are for reference and the calipers are for accuracy. Both ends of each blank should be fitted to the pen parts for the best fit. Keep those calipers handy and if you don't own any the best investment you could make would be to buy some.
Do a good turn daily!
Don

Originally posted by Fangar
<br />Russ raises a good point (For once... Geeze []). I use a digital caliper and only use the bushings as a reference. The unfortunate thing is machine tolerances in bushings. I have had bushings off by as much as almost 3 thousanths. I have machinist friends who constantly have to work at maintaining precise tolerances. There is no set it an forget it. Bruce Boone will likely attest to this having experienced it in his line of precise work.

Fangar

 

[Dario]

Yep, calipers are indespensible. [^]

That is why I love the bushing chart that Huzzah made. I don't have to measure the kit every now and then...just flip through the pages of my binder for that particular pen. [^]

I also use it for all other notes I may have for that particular kit.

 

[Randy_]

Originally posted by Dario
<br />Yep, calipers are indespensible. [^]

That is why I love the bushing chart that Huzzah made. I don't have to measure the kit every now and then...just flip through the pages of my binder for that particular pen. [^]

I also use it for all other notes I may have for that particular kit.

Dario: That is a dangerous shortcut and sooner or later, you will get burned. If tolerances can vary so much on bushings, they will also vary on the hardware as well. The "BEST" method to assure a good fit would be to measure the hardware of each kit before you turn it!!

 

[Dario]

Randy,

I do measure my kit first and compare it with his chart. Unlike the bushing which can be sanded, the chart sizes will not change. Are you saying that the kit sizes vary also?

 

[its_virgil]

The parts in (for example)baron kit A and baron kit B may vary....I mike the parts that transition to the wood on each and every kit. It is now part of my routine...I'm not Randy...hope my answer counts.[]

Originally posted by Dario
Do a good turn daily!
Don

<br />Randy,

I do measure my kit first and compare it with his chart. Unlike the bushing which can be sanded, the chart sizes will not change. Are you saying that the kit sizes vary also?

 

[Randy_]

Originally posted by Dario
<br />Randy.....Are you saying that the kit sizes vary also?

Yes. Dario. That is exactly what Don and I are saying!! The kit hardware "MAY" vary, too. You have to check every kit if you don't want any surprises. I can't tell you if it is 1 in 10, 1 in 100 or 1 in 1000; but there is going to be some variation and it is bound to be that extra special blank when the problem occurs. It only takes a few seconds to mike the hardware and write down the dimensions....just not worth taking a chance on screwing up a nice blank , IMHO!!

 

[Dario]

Randy and Don,

Thanks! I never thought of that []. I guess I give the kit manufacturer's more credit than deserved. []

 

[RussFairfield]

Beginners should pay attention. There is a point here that is always missing from our discussions of bushings, and that is how we use them. These messages are from folks with pencrafting experience. None of them rely on the bushings for the final sizing the wood pen barrels.

I hope the beginners to pencrafting are getting the message that one of the biggest improvements in the quality and fit of our pens is an investment in a dial caliper. That allows us to fit the wood to the metal pen parts, and not use the bushings to determine the diameter of the pen barrel. Yes, it takes longer to do it this way, but the results are worth the extra time.

 

[Firefyter-emt]

OK, as a newbie.. Here is a question, I have started doing this myself. I will take the tip on measureing the hardware itself too. Diffrent wood sand slower or faster. How close do you typicaly turn the wood before you start with the sandpaper? Do you keep the same spec or thicker for softer woods?

 

[Dario]

No easy answer to this one.

It all depends on how smooth you turn your wood.

If you can really get smooth finish (and level) enought then stop where you can just sand with 320 grit. Meaning almost right on the exact size. IF you are having tear out, etc. then you have to stop much sooner than that and pull a much coarser grit sandpaper.

As a rule, harder wood won't get cut by sandpaper as deep or as easily as softer wood. It can be good or bad depends on how you look at it. Good because the chances of you accidentally having a geep cut is less but bad since it will take longer to sand down if you need to.

Hope this helps

 

[blodal]

I really love this site!!!!! Thanks guys for your expert input on this topic. Learning on your own is challenging, but the advice here is a tremendous help.

Keep up the good work.

 

[its_virgil]

And the thickness of the finish comes into account. I use 4 coats of med CA and that builds somewhat. When I do lacquer, the buildup is less. I use a skew and get a very smooth surface after final cut. Start sanding with 320 or 400, then 600 then MM before CA. The sanding removes liitle material. I think I'll do a test barrell, measure before and after sanding and after finishing and record the measurements so I'll know how to answer this question next time it comes around. The more pens one turns the more automatic this comes. I wish I could give some numerical measurements. Maybe someone else is more organized than I and already has these measurements. Interesting thread!
Do a good turn daily!
Don

Originally posted by Dario
<br />No easy answer to this one.

It all depends on how smooth you turn your wood.

If you can really get smooth finish (and level) enought then stop where you can just sand with 320 grit. Meaning almost right on the exact size. IF you are having tear out, etc. then you have to stop much sooner than that and pull a much coarser grit sandpaper.

As a rule, harder wood won't get cut by sandpaper as deep or as easily as softer wood. It can be good or bad depends on how you look at it. Good because the chances of you accidentally having a geep cut is less but bad since it will take longer to sand down if you need to.

Hope this helps

 

[alparent]

So basicly getting a set of bushing matching every new kit I'm trying, is a wast of money! Since I can't relly on them for size, they only serve to hold the blank. So getting a set of bushing for every tube size and using the calliper make more economical sense? So why are we all buying all of those bushings then?

 

[Dario]

Originally posted by blodal
<br />I really love this site!!!!! Thanks guys for your expert input on this topic. Learning on your own is challenging, but the advice here is a tremendous help.

Keep up the good work.

One thing for sure...whenever Russ, James, Don, Randy, Wayne, Lou, Anthony, Jim, Paul, William, Bruce, Michael, Mudder, Frank, Billy, Gerry, etc. (sorry can't name everyone here) opens their mouth or start typing [], I try to listen/read well because it is always "meaty".

I've got so much respect for these guys. [^][^][^]

 

[Dario]

Originally posted by alparent
<br />So basicly getting a set of bushing matching every new kit I'm trying, is a wast of money! Since I can't relly on them for size, they only serve to hold the blank. So getting a set of bushing for every tube size and using the calliper make more economical sense? So why are we all buying all of those bushings then?

It is not a waste since you use it still as a guide...but the message is do not rely on it too much.

Other bushings also have a shim to make the tube properly get centered on smaller mandrels which you cannot easily make yourself.

All in all as imperfect as they are, they are worth the money if you want to make descent pens.

 

[alparent]

Originally posted by Dario
<br />

Originally posted by blodal
<br />I really love this site!!!!! Thanks guys for your expert input on this topic. Learning on your own is challenging, but the advice here is a tremendous help.

Keep up the good work.

One thing for sure...whenever Russ, James, Don, Randy, Wayne, Lou, Anthony, Jim, Paul, William, Bruce, Michael, Mudder, Frank, Billy, Gerry, etc. (sorry can't name everyone here) opens their mouth or start typing [], I try to listen/read well because it is always "meaty".

I've got so much respect for these guys. [^][^][^]

I could say the same thing but I would add your name to the list.
Not sucking up, just giving due respect where it's needed.

 

[its_virgil]

Alain,
A waste of money, not at all...or maybe yes. I have a set of bushings for each kit style. I find it easier to grab a kit and grab the bushings for that kit than to grab a kit and then figure out which bushing set will work. It was much easier in the beginning to have bushings for each kit. I could probably work with fewer bushings set now, but I still have bushings for each kit style and still use them, but for reference only. Bushings are relatively inexpensive and they last a long time. There are stepped bushings that have several tube sizes available, or thay could be machined.

I make a couple of pens from CSUK and they have no bushings for them. I make my own from aluminum, corian, or other material. Remember, they are used for reference only.

Do a good turn daily!
Don





<br />

Originally posted by alparent
<br />So basicly getting a set of bushing matching every new kit I'm trying, is a wast of money! Since I can't relly on them for size, they only serve to hold the blank. So getting a set of bushing for every tube size and using the calliper make more economical sense? So why are we all buying all of those bushings then?

 

[Mudder]

Very good thread with lots of useful information.

I can’t help but to wonder if some folks over do it a little though. A caliper or a micrometer are always within arms reach whenever I’m turning on the lathe. And being that my 9 to 5 is being a Quality “Stupidvisor†I tend to want to turn my pens to .001†of the kit diameter but I can tell you that I seriously doubt that you can see or feel if you are off by up to .003â€. Another thing I’ve seen and I’ve seen it on slimlines and cigars mostly is that the diameter that presses into the tube at the nib is not concentric with the outside diameter.I have also seen a few parts where circularity left a lot to be desired. I guess my point is that with all of the variables like finish thickness, plating variances, shrinking or swelling of wood and a whole host of other things, If I end up within .004†of my target diameter I’ll stick a fork in it and call it done. I would sure like to hear from other penturners as to what they consider to be their “acceptable toleranceâ€?


What say you?


Definitions:

Concentricity- Two or more features sharing a common axis or center point.

Circularity- The apparent roundness of a 2 dimensional figure


&lt;Edited to add definitions&gt;

 

[Mudder]

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47257

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5658

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47256


All fine tools and well worth the investment.

 

[alparent]

Originally posted by Mudder
<br />I would sure like to hear from other penturners as to what they consider to be their “acceptable tolerance�

If it look good to my eyes and it feels good to my fingures!
That good enought for me.

 

[PenWorks]

I always use two sets of bushings for turning. One set is for cutting only, Visually, they always retain their squareness and I mic the ends. After turning, I replace the bushings with my old worn out ones. I do my sanding and finishing with these. They are ussually so worn and coated with finish, I get no metal carry over onto my wood. Also forces me to mic the ends because they are so worn out. Just happens to work for me.

 

[airrat]

Its funny how far off bushings can be. I bought a set of Cigar bushings from Woodcraft due to Robert(Hastur) and I having to turn alot of them for an order. Just curious to see if they were the same I micro'd them. I was shocked.

I do believe it is time to get in the habit of doing it to all pens as I turn.

 

[blodal]

Originally posted by alparent
<br />

Originally posted by Dario
<br />

Originally posted by blodal
<br />I really love this site!!!!! Thanks guys for your expert input on this topic. Learning on your own is challenging, but the advice here is a tremendous help.

Keep up the good work.

One thing for sure...whenever Russ, James, Don, Randy, Wayne, Lou, Anthony, Jim, Paul, William, Bruce, Michael, Mudder, Frank, Billy, Gerry, etc. (sorry can't name everyone here) opens their mouth or start typing [], I try to listen/read well because it is always "meaty".

I've got so much respect for these guys. [^][^][^]

I could say the same thing but I would add your name to the list.
Not sucking up, just giving due respect where it's needed.

I second that. Add Dario to the list.

Thanks Dario!

 

[Randy_]

Originally posted by Mudder
<br />.....but I can tell you that I seriously doubt that you can see or feel if you are off by up to .003â€.....

I haven't ever run an actual touch test, myself, to see what I could feel and what I couldn't; but I have read that the average human being cannot detect an offset of less than 0.003", so Scott is right on target unless he runs into someone with super sensitive fingers.[^][^]

 

[Randy_]

http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemid=40926&CategoryName=&SubCategoryName=

Perhaps this should be a discussion for another thread(?) but since the subject has been raised here.....

I've used a standard manual vernier that I purchased many years ago in its home country of Japan. It has served me well; but as the years pass by it gets harder and harder to read. When I took up pencrafting , I decided it was time to get a vernier that was a little easier to read. The obvious choice was a one with a digital readout. However, during my research, I found quite a few comments indicating that the digitals consumed batteries like candy, particularly if you got one without an automatic cutoff function. Knowing myself, I knew it would be frustrating as #### to want to take a measurement only to find out the battery was shot so I opted for a dial caliper.

I was concerned about the possibility of the delicate rack and gear mechanism of a dial caliper getting corrupted by the dust and chips of a woodworking shop and asked about that issue on several different woodworking forums. Multiple responses from experienced woodworkers suggested that it was not a problem. I am careful to keep the tool in its case when not in use and I blow it out after every use with compressed air. Had it about 2 years now without any problems. I bought the one linked above from Harbor Freight.....a little under $25 IIRC. It measurer's in metric units and inches. That means there are two pointers instead of one; but you really can't get them mixed up.

BTW, Apparently, they only sell these in the retail stores as I could not find this model on the HF Internet store.

 

[RussFairfield]

Most people can feel the thickness of a sheet of 20 lb. copy paper on a smooth surface and that is 0.0024" for the paper that I use.

I don't know about the others, but I prefer the wood to be slightly larger than the metal fitting, and not the other way around.

A cut depth of 0.005" is relatively easy to do with a sharp skew; but it does take some practice to do that with any consistency.

I saw the biggest improvement in the roundness and concentricity of my pen barrels when I started using a collet chuck to hold the mandrel.

 

[Mudder]

Originally posted by RussFairfield
<br />Most people can feel the thickness of a sheet of 20 lb. copy paper on a smooth surface and that is 0.0024" for the paper that I use.

I use several taper rods at work to set snap gages for the centerless grinders they usually begin on one dimension and then have a taper up to the next dimension that is .002 bigger
I.E. it will be .2500 for 1 inch and taper up to .2520 and .2540 and so on for .010 over a 6†legnth. If there was not a mark where the taper is I would defy anyone to tell me the difference of .002 or .004 by feel. I’m holding a cheap blur papermate pen right now and it tapers .008 from end to end. I doubt that you can detect the taper using your fingers.

I would suggest two things:

I doubt that you are feeling the thickness of the paper, instead your brain is interpreting the abrupt edge, the visual queue and the change in texture and registering that as a change.

Second, if your 20 lb bond is only .0024 then there is a problem. One of our major customers is a company who manufactures high speed mail sorting and envelope stuffing machines and their engineer confirmed that the industry standard thickness of 20 lb bond paper is from .0031 to .0042.

 

[RussFairfield]

I was not trying to get into an argument over specifics with anyone. I quit being specific about anything when I quit working. Life is easier and less stressful that way. I now use Pi=3, because that is close enough for me; and I no longer wear a watch because I can guess the time within an hour, and that too is close enough for me.

What I was trying to do was illustrate that we can feel the difference in small increments of dimensional change at an abrupt edge, as in the joint between the wood pen barrel and the metal fitting. I can feel the step between the wood and the metal when it measures about 0.003", and I can see the step when it reaches 0.010". Personally, I can keep the step to less than 0.005" with some consistency. I don't always get that closw a fit, but that doesn't mean I shouldn't try. Others will have different abilities and have a difference of opinion as to what is good enough for them, and I have no problem with that.

As for the actual thickness of a sheet of paper, I looked at what I am using and it says 18-pound on the label and it measures 0.0024" thickness with the old 0-1" micrometer. I do buy cheap paper, so I am probably getting what I am paying for. []

 

[Randy_]

Since I just happen to be sitting with my vernier in hand as I just finished a post about same, here are some items to consider. Don't know that they answer the question; but they do add a few pieces to the puzzle.

Originally posted by RussFairfield
<br />....Most people can feel the thickness of a sheet of 20 lb. copy paper on a smooth surface and that is 0.0024" for the paper that I use.....

According to my actual measurements:
Scotch tape = 0.002"
Newspaper = 0.003"
15# Printer paper = 0.0035"
20# Copy paper = 0.004"

Originally posted by RussFairfield
<br />....I doubt that you can detect the taper using your fingers.....
I doubt that you are feeling the thickness of the paper, instead your brain is interpreting the abrupt edge, the visual queue and the change in texture and registering that as a change.

Scott:Yes and no. I agree with your analysis that detecting paper thickness has to do with changing texture, visual cues etc; but your suggestion about detecting tapers is not germane to this discussion. We are talking about detecting a discrete "STEP" in diameter between pen hardware and wood.....the most common interface where this is a problem is at the tip where the pen is held.

I just performed the following experiment for fun....don't know if I am typical or not; but this is what I found. First off, I laid one piece of newspaper on top of another and without looking, ran my finger across the paper. The "step" from one page to the other was very noticeable; but I do not think it would be objectionable at the tip/wood interface on a pen. Next, I did the same thing with Scotch tape.....used two pieces so there would be no change of texture. Again, without looking, I could feel the "step"; but just barely.....don't think it would be detectable on a pen by the average person?? And finally, I got out a pen that was given to me....a PSI Traditional Roller Ball.....as an evaluation pen by a new turner. The wood was proud by anywhere from 0.004" to 0.0065". At the larger end, the difference was very obvious visually and tactilly and I would guess that most people would notice it. At the lower end the difference was not so obvious. I would guess that pencrafters and discerning buyers would notice it; but that the average pen buyer probably would not.

 

[Randy_]

Originally posted by RussFairfield
<br />.....and I no longer wear a watch because I can guess the time within an hour, and that too is close enough for me......

Yeah; but is it close enough for your wife when taking her out to dinner??[][]

 

[sptfr43]

when I first started turning pens I tried to work from the bushings but found that I get better results by measuring the hardware at each end of the tubes and using my digital caliper to tell me when I am at the right size. so as long as the bushing holds the blank from wobbling on the mandrel they are good enough

 

[leehljp]

Thanks Randy, on the comments on the vernier VS digital readouts. I was thinking about this too. I think the better digitals today have better battery usage electronics. I know that many digital camera batteries last a full ten times longer today than 4 years ago due to electronic changes. I do appreciate the vernier when comparing sizes, but like the digitals when I just want to know a single reading. Watching the needle go back and forth between two sizes does something in my brain that digital reading changes do not.

ON Thickness differences - feeling and seeing - a Japanese friend adjusts his planes (as are most Japanese planes) by tapping the end of the plane with a hammer and eyeballing it. Below is the wood shaving result of his tapping and eyeballing the difference. His comment to me was that it was not a sharp or adjusted as fine as it could be, and he was dead serious.

 

[Mudder]

Originally posted by Randy_
<br />
We are talking about detecting a discrete "STEP" in diameter between pen hardware and wood.....the most common interface where this is a problem is at the tip where the pen is held.

O.K.

Now having said that and knowing where the problem is I'm left to wonder why in the world you would leave the edge square so that it could be felt at all? I always use a Inside / Outside chamfer tool that I used in my reloading days to take any sharp edge off. the tiniest little broken edge makes a world of difference. I have yet to cut through my finish and I have NEVER had anyone complain about my fit near the nib.

BTW: Bill B. sells this very tool

http://www.arizonasilhouette.com/Chamfering_Tool.htm

Originally posted by Russ Fairfield
<br />
Others will have different abilities and have a difference of opinion as to what is good enough for them, and I have no problem with that.

I'll have to agree with you here. Far be it for me to say that you are wrong. You use what works for you and I use what works for me, and I have no problem with that either.

 

[Randy_]

Originally posted by Mudder
<br />.....I'm left to wonder why in the world you would leave the edge square so that it could be felt at all? I always use a Inside / Outside chamfer tool that I used in my reloading days to take any sharp edge off. the tiniest little broken edge makes a world of difference. I have yet to cut through my finish and I have NEVER had anyone complain about my fit near the nib....

Scott: The point is that if the wood is the correct diameter(same as the hardware), there will be "NO" step to feel. If the turned blank is slightly oversized, then chamfering the edge a little will certainly help the situation. On the otherhand, if the blank is spot on or a hair undersized, then chamfering the blank will make it shy of the hardware and you may feel the metal extending beyond the wood.

 

[Mudder]

Originally posted by Randy_
<br />

Originally posted by Mudder
<br />.....I'm left to wonder why in the world you would leave the edge square so that it could be felt at all? I always use a Inside / Outside chamfer tool that I used in my reloading days to take any sharp edge off. the tiniest little broken edge makes a world of difference. I have yet to cut through my finish and I have NEVER had anyone complain about my fit near the nib....

Scott: The point is that if the wood is the correct diameter(same as the hardware), there will be "NO" step to feel. If the turned blank is slightly oversized, then chamfering the edge a little will certainly help the situation. On the otherhand, if the blank is spot on or a hair undersized, then chamfering the blank will make it shy of the hardware and you may feel the metal extending beyond the wood.

Again you leave me wondering.

Why in the world would you assemble a pen if you know the wood is smaller than the fitting? I was taught that you can always take a little more material off but it's real hard to add material. And I disagree with you in one respect. If the blank was "spot on" the tiny chamfer that I put on my blanks would not be noticible. Since I would not assemble a pen where the wood is shy of the fittings I cammot comment on the rest.

You use what works for you and I will use what works for me.

 

[opfoto]

Thanks for all the great info....

I will Mic <u><b>BOTH</b></u> the barrells <u><b>AND</b></u> the pen hardware on all future pens that I turn from now on. This site never ceases to amaze me!!!!

 

[alparent]

I don't use a calliper anymore. I use something like this :

<br />

Don't need to bother with numbers.

I adjust it to the actual hardware I'm going to use and I'm always on the dot!

 

[Dario]

Originally posted by leehljp
<br />Thanks Randy, on the comments on the vernier VS digital readouts. I was thinking about this too. I think the better digitals today have better battery usage electronics. I know that many digital camera batteries last a full ten times longer today than 4 years ago due to electronic changes. I do appreciate the vernier when comparing sizes, but like the digitals when I just want to know a single reading. Watching the needle go back and forth between two sizes does something in my brain that digital reading changes do not.

ON Thickness differences - feeling and seeing - a Japanese friend adjusts his planes (as are most Japanese planes) by tapping the end of the plane with a hammer and eyeballing it. Below is the wood shaving result of his tapping and eyeballing the difference. His comment to me was that it was not a sharp or adjusted as fine as it could be, and he was dead serious.

WOW!!! [:0][:0][:0]