Puzzled about mandrel bushings

[Bobalu]

During my short time in this hobby, I've learned that most pen/pencil kits are made by a small number of overseas manufacturers. What I'm wondering is are there any standards held to by these manufacturers? In other words, can I buy pen kits and related bushing sets from one source and expect these bushings to work with the same type kit purchased from another source. An example being if I buy a Cigar type pen kit and bushings from Rockler today, and purchase a Cigar type pen kit from Woodcraft next week. Can I use the Rockler bushings with the Woodcraft kit? I've checked some of the data sheets available in the IAP Library, but at this time I'm just too green to make any sence of all this.

 

[ed4copies]

Welcome to IAP, Bob!!! Stick around, you'll learn lots!!!

Your question gets a definite MAYBE!! There are a few manufacturers and they do NOT have a standard. So, if you use two sources who are using the same manufacturer, it will probably be the same kit. BUT, it MAY not be!!

Bushings are cheap. Sometimes they are drilled off-center, too, so if your pens are not "round", this is a possibility. But, I would suggest getting them from the same source as your kits. Also don't mix Rockler cigars in with Woodcraft cigars or you COULD have a problem----or not.

Woodcraft is purchasing from Berea. I don't know who Rockler is using.

 

[tim self]

Like Ed said.

Yes Bob, these bushing/kit combo's are sometimes interchangable. Cigar is a cigar, Sierra is a Wallstreet, Sierra vista is a Wallstreet III. Typhoon, baron, navigator, sedona uses all same bushings. But to know for sure, measure the kit and check your bushings to it.

That being said, you may/will find there are some minute variations with the diameters by thousands of an inch. Currently the only true exact bushings found are from JohnnyCNC.

Hope this confuses you a bit more. JK. Never be afraid to ask here.

 

[randyrls]

if I buy a Cigar type pen kit and bushings from Rockler today, and purchase a Cigar type pen kit from Woodcraft next week. Can I use the Rockler bushings with the Woodcraft kit? I've checked some of the data sheets available in the IAP Library, but at this time I'm just too green to make any sence of all this.

Welcome Bob!

The short answer is that you should not depend on the dimensions of any bushing. Use calipers to measure the fittings directly and match the blank size to the fitting but DO check the bushing size. Cheap Harborfreight digital calipers go on sale for about $10 on a regular basis.

Cigar pens especially seem to very quite a bit in sizes of the fittings.

 

[jkeithrussell]

www.penturnersproducts.com

Use those bushings, and you will never go wrong.

 

[Bobalu]

I was sort of afraid of asking this question, as I thought it was kind of stupid. Glad I did now. Looks like I'll have to keep the various bushing sets better segregated from each other. Perhaps I'll dedicate one of those parts boxes to just bushings and label them as to pen type and source. I'll also use randyrls's advice and get my calipers out and check the fit of the parts versus bushing size. I know I have at least four calipers somewhere under all this stuff on my workbench. Thanks to all for your assistance.

 

[KenV]

Welcome to the world of TOLERANCES and ACCURACY and PRECISION -- and lots of folks (even here) get them mixed up in usage. All those maybe's above are about tolerances between runs and variation in the accuracy as compared to specifications. Then there are the differences in the precision of different measuring methods and tools.

All mandrels are not the same size with different manufactures having different tolerances though they are all close to dead on a "D" size on the drill pit charts.
Bushings from one supplier may be too tight or too loose on another supplier's rods.

The cheap Harbor Freight calipers may or may not work for you depending on what you do. They do not work well for me for measuring against a fixed standard and I use better grade gear for that. One that reads to the 0.001 may work adequatly for comparing two measurements -- such as outside of fittings to be compared to finished diameter of a turning. The actual dimension is not especially important, but the difference between two reading is important.

I pay the price of Mitutoyo, Starrett, Brown and Sharpe for accurancy, but use the consumable throwaway HF stuff for relative measures. Every one get to decide what is important at what price (value) and make choices.

 

[Daniel]

Definitly not a stupid question. Actually one of the more confusing areas of pen turning. as a lat ditch safety factor always order bushings until you know otherwise. you will eventually be glad you have that extra set if that is all it ends up being.

Another question you should not be afraid to ask is if someone will measure the parts of any particular pen so you can confirm if you do have the right bushings. somebody has one of just about anything around here at any given time.

 

[its_virgil]

For the most part Rockler resells Berea kits also but not in all plating choices.They do sell a few non berea kits such as the gent and majestic...so they may have started importing their own kits from Dayacom.
Do a good turn daily!
Don

Woodcraft is purchasing from Berea. I don't know who Rockler is using.

 

[snyiper]

www.penturnersproducts.com

Use those bushings, and you will never go wrong.

+2 The man is great to deal with and has answered countess of my newbie questions. His work is second to none. That was my first investment was bushings from him.

 

[GouletPens]

The answer to your question is about the same as what the TARP funds are being used for.....we like to think it's working in our favor, but we REALLY JUST HAVE NO IDEA:wink:

 

[Wayne]

Bob, thats the same problem that too many of us deal with daily. So in an effort to help with this I'm putting together a chart to eliminate some of this.

Take a look at http://www.penturners.org/forum/showthread.php?t=50717 and I still need some feedback from others to fill in the blanks.

The downloadable chart is not the complete chart, this has only the missing info that I need.

 

[John Eberly]

Welcome Bob!

The short answer is that you should not depend on the dimensions of any bushing. Use calipers to measure the fittings directly and match the blank size to the fitting but DO check the bushing size. Cheap Harborfreight digital calipers go on sale for about $10 on a regular basis.

Cigar pens especially seem to very quite a bit in sizes of the fittings.

I agree with Randy - Use some calipers to size your work to the hardware in the kit.

Sizing by the bushings invariable requires you to put your skew against the bushing - bad for both. You're also subject to a changing bushing diameter - they wear from turning and sanding, and CA builds up on the diameter during finishing. After a dozen pens, the bushing is only an approximation of it's original size - and that size probably was not a perfect match to the hardware anyway.

Once you make this transition, the only critical dimensions are the tube and mandrel diameters and the concentricity of the bushing and center hole. In other words, now you only need one set of 10mm, one set of size O, one set of whatever. There are some oddballs like the Euro and Roundtop with different ways of dealing with tenons, but you can really work with fewer bushings.

Buy and use some calipers.

 

[GouletPens]

For that matter, you can turn between centers and forget the mandrel and bushings altogether. It'll take longer, but will be more accurate in the end.

 

[Rifleman1776]

A good question. No doubt, getting started is confusing.
But, the answer to your question is: yes, no, maybe and sometimes.
Actually, Daniele gave the most definitive response.
But, the one response that has not been posted, until now is: don't sweat it.
Bushing are cheap and should be considered disposable items. Buy a set whenever you get some new kits. Keep kits and matching bushings together. Throw away bushings when they get worn or damaged.
And, as Brian suggested, with larger (anything other than 7mm pens) pens, try the 'no mandrel' technique.