about mandrels and bushings

[radhak]

I want to start turning pens, and hence - need to buy 'stuff'.

I got my lathe, and i got the basic set of tools from PSI. Now I know I need pen kits, and blanks.

But first, I need mandrel(s)? It looks like the 7mm mandrel is the most available, but is that only for the slimline pens? How about the others - the comfort pen, the cigars? Do I need different mandrels? And what are bushings? Don't they come part of the pen kits?

I did look at past threads, and even pages by Ray Girling and Tom Hintz; got a lot of info and techniques, but frankly, got a bit dizzy, and am not sure this particular info is there; maybe i missed it !

[Russianwolf]

There are only two mandrel sizes available. A sized which will slide inside a 7mm tube, or B sized (only used for some Berea kits) that is slightly larger (a 7mm tube will slide inside a B bushing). The A is the more widely used one, but the B is slightly less prone to flexing. All the stock bushing available (Cigar, Sierra, Baron etc.) run on the A unless they are specific to the Berea B mandrel.

You need the widely available A sized for turning most pens. Get the adjustable type as you can reduce the length and reduce the flex easily.

Now, you don't really need a mandrel. You can turn between centers using most bushings except the standard 7mm and B bushings. Meaning the bushing has to be a stepped shape that allows the tube to slide over a portion of it for between center turning. The Cigar bushing for example slides onto a 7mm mandrel, but the tubes are 10mm. They rest on the steps of the bushing instead of the mandrel itself.

You would need to get a dead center for between center turning (about $5) and in either case you will need a 60 degree live center (about $15). The end of a mandrel with destroy the tip of the stock live center in short order. Both can be had from Grizzly, or several other places.

[leehljp]

There are two mandrels sets: "A" or 7mm and "B" which actual size I forgot. The purpose of the "B" set was a larger size to prevent mandrel flexing as sometimes happens with the thinner "A" mandrel. Also the A is subject to becoming bent.

However, you will not get to "choose" which mandrel you want to use, as that is determined by the pen kit and supplier. If you find a specific pen you really want to make and it is only available to one mandrel or the other, then that becomes the determining factor. Most kits use "A" mandrels.

The "Flexing" of the "A" mandrels is more of a result of bad technique and experience than anything else, although many people will argue about that. The flexing or minutely' bent mandrels cause pens to be Out of Round (OOR). When it comes down to it, the pressure of dull chisels or having the tail stock to tight will cause this. There are other problems that cause the similar problems too.

Mandrels have a small cup in the end for the live center of the tail stock to fit into. This cup is 60°, so the meaning here is that you will need a 60° live center to operate the mandrel correctly. Many people, when they start out, use the live center that comes with the lathe which is 30°. The 30° point or tip does not fit properly, and will eventually bend, which will result in OOR pens.


All pen kits need bushings, but they don't come with the pen kits themselves. They have to be ordered separately. I would recommend purchasing two sets of bushings to always have an extra set on hand. Also look at the drill bit size and make sure you have that drill bit on hand, or at least order one. Just about every pen kit around uses different sized bits.

If you are close to a Harbor Freight, get their 100+ drill bit set that has lettered bits, numbered bits and fractions. This will help to have a bit close to most sizes of pens that you will make for a while. However, some pen kits come with the need for metric bits.

Also, while you are at HF, get a set of their punches, which are great for disassembly when something goes wrong.

Hope I haven't scared you off.

As and add in: Mike mentioned Mandrel-less/No Mandrel turning. I have been doing it that way for over a year and am sold on it. However you will need special hard to find bushings if you turn slimlines. Otherwise slimlines will have to be turned on mandrels.

[Uncle Cracker]

You will want to lurk around on this site for some great info. You will recognize both the above shady characters over there as well.

[radhak]

Thanks, Mike and Hank. That clarifies things a bit for me. Yes, HF is close-by, so that should help. But need to surf PennState now, I think.

I'm hoping to make mech-pencils for my girls as my first - would be appreciated, and not as critical . Wonder if I could use Acrylic blanks for those.

[Russianwolf]

Thanks, Mike and Hank. That clarifies things a bit for me. Yes, HF is close-by, so that should help. But need to surf PennState now, I think.

I'm hoping to make mech-pencils for my girls as my first - would be appreciated, and not as critical . Wonder if I could use Acrylic blanks for those.

oooo... the mechanical pencils that are available aren't too highly thought of. especially the 7mm pencils.

There are some sketch pencils that are good, but you may want to go to the site that UC pointed to and do more research before buying something that might break in a couple months.

The acrylics are nice, but shop around for good prices. www.woodpenpro.com has some really nice ones.

[radhak]

UC, thanks for that link...I think - that's a place to get lost in ...!

And mike thanks again - for the opportunity to spend more money...!

[Russianwolf]

UC, thanks for that link...I think - that's a place to get lost in ...!

And mike thanks again - for the opportunity to spend more money...!

Sorry, but in the last 2 days I've spent well over $300 on this "hobby". And that's just turning material, no kits, and no tools.