Dull Pen Blank Trimmer...

[Derek Arita]

Anyone here know how to sharpen a pen blank mill? Mine went dull and I hate to just junk it and pay for another.

[Peter Christensen]

Have you got a disc sander?

[John K Jordan]

Anyone here know how to sharpen a pen blank mill? Mine went dull and I hate to just junk it and pay for another.

I sharpened mine with small diamond hones, these:

373508

That was years ago (I seldom turn pens) and I can't remember without going to the shop to look whether I sharpened the bevels or the flats of the cutters. In general, it's best not to mess with bevels so I probably sharpened the flats if I could reach them OK with the hones. I've also used small diamond files to sharpen other cutters similar to those on the pen mill.

JKJ

[Len Mullin]

Derek, it doesn't take much to resharpen them, and yes you sharpen the flats. A grinder is not the way to do it, because it's very hard to hold them perfectly flat against the grinder wheel. You could use what John has posted, they would do a descent job. But I found the best and easiest way to resharpen is, a flat diamond coated plate. Using that type is the easiest and best, because it is very easy to hold the head of the trimmer flat and removes the least amount of material to be sharp.
Len

[Derek Arita]

Thanks. Ya, its to the point that the mill is burning the blank ends rather than cutting them. Of course, the duller it gets, the harder I press, the more it burns, etc. It's past due.

[Len Mullin]

Derek, when you sharpen it, make sure that the mill is held 90* to the sharpening object. If not, you will either ruin the mill or have to resharpen it all over again. In my previous posting, I said to hold the head flat. I should have said 90* to the diamond plate, not flat.
Len
Len

[Jerry Rytter]

I tossed mine just use my disc sander make sure it is 90 degree

[Kyle Iwamoto]

I tossed mine just use my disc sander make sure it is 90 degree

Since the Jet mini faceplate is pretty much useless, I turned it into a disc sander. Use plywood, turn a circle and use 5" PSA discs and you got a nice disc sander. Use "good" plywood. I guess you could use anything, just that plywood scrap was handy. Your tool rest helps a lot maintaining close to 90.

[Bob Bouis]

Disc sanders don't work for squaring up pen blanks unless you have a jig that holds the pen by the tube. But otherwise, yeah, it works well, especially for squaring up the blank after applying finish. The darn mills can and will chip off CA finishes.

[Marvin Hasenak]

If you have a set of the Harbor Freight transfer punches, you can use a drill chuck in the tailstock to hold the correct size punch and slide the blank on it to square it off on a sanding disc in the headstock. I use 1.1/2" peal and stick discs on a homemade sander that I drilled and tapped to fit the threads.of my lathe.

[John K Jordan]

Disc sanders don't work for squaring up pen blanks unless you have a jig that holds the pen by the tube. But otherwise, yeah, it works well, especially for squaring up the blank after applying finish. The darn mills can and will chip off CA finishes.

Hmm.. I've only made a few dozen pens over the years (usually when a teen wants to "make" one) but I've never squared after applying finish. I always drilled, glued, squared, turned, finished, then removed just any overrun glue gently with the trimmer without taking off any of the wood. Any extra CA on the ends just scrapped off with no chips.

Is there an advantage to trimming after finishing?

JKJ

[Bob Bouis]

Generally you wouldn't remove any wood (or very little), but you always have to remove the glue from the ends or the parts won't fit together right.

But, yeah, sometimes the ends get out of square somehow. Could be stress being relieved when you cut the blank down, could be distortion from being clamped on the mandrel, heat from sanding -- who knows. Or maybe just weren't squared perfectly to begin with, but since it's right before you fit the parts, after finishing is the best time to square everything up once and for all.

The trimmers don't always chip CA glue off, but it happens consistently enough to ruin your (my) day. Maybe if I sharpened it? I find it inexplicable that even an expensive trimmer like the whiteside is made from carbon steel.

[Scott Kuykendall]

Here is one way to do it.
http://www.penmakersguild.com/articles/penmillsharpening1.pdf
Scott

[Peter Christensen]

There is a gent that you can reach on the IAP in their market place section, Rick Herrell that makes an offset tool for the tailstock that holds transfer punches. Lets you use more of the sand paper instead of just the centre of the disk.

I use a simple to make jig for my disc sander and transfer punches. If you don't have a mitre gauge you can just put the jig on a stick that fits the slot.

[Marvin Hasenak]

I square my blanks before I turn them, so I have never had an issue of chipping CA finish.
As to being square, my disc sander is squared to the transfer punch by using a large Forstner bit in the drill chuck in the tailstock.

[John K Jordan]

Generally you wouldn't remove any wood (or very little), but you always have to remove the glue from the ends or the parts won't fit together right.

But, yeah, sometimes the ends get out of square somehow. Could be stress being relieved when you cut the blank down, could be distortion from being clamped on the mandrel, heat from sanding -- who knows. Or maybe just weren't squared perfectly to begin with, but since it's right before you fit the parts, after finishing is the best time to square everything up once and for all.

The trimmers don't always chip CA glue off, but it happens consistently enough to ruin your (my) day. Maybe if I sharpened it? I find it inexplicable that even an expensive trimmer like the whiteside is made from carbon steel.

That makes sense. I've removed excess glue from the ends lightly with the trimmer but usually by hand with 600 grit paper. Maybe I haven't done enough pens to run into distortion. I can't imagine clamping hard enough to distort and my instinct tells me sanding heat would not be good for anything - I sand at low speeds to avoid any heat. I made conical bushings from HDPE just for finishing so excessive pressure is unlikely.

About carbon steel vs HSS: we turners love our HSS but I understand the principle advantage is how they can take incredible heat in the hands of amateurs with bench grinders without losing hardness. In fact, machinist TubalCain says in one of his books that high carbon steel can be made both harder and sharper than HSS. (I think I can find the reference if anyone is interested.) You just can't grind it casually. Something like a pen trimmer probably won't be sharpened on a bench grinder so the carbon steel may be fine.

JKJ

[Bob Bouis]

Maybe it's possible to make carbon steel with edge retention as good as high speed steel, but it doesn't seem like they bother with that for pen trimmers. The ones I have dull really easily. I'd say they last about as long in wood as cheap HSS bits last in mild steel.

[Marvin Hasenak]

The easiest way is to turn the blank to 3/4 or 5/8 and use a collet chuck to drill the blank. Glue in the tube, then square it using a drill chuck in the tailstock with either a pen mill, a router bit or a sanding disc, or a Forstner bit with the nob ground off.

[John K Jordan]

The easiest way is to turn the blank to 3/4 or 5/8 and use a collet chuck to drill the blank. Glue in the tube, then square it using a drill chuck in the tailstock with either a pen mill, a router bit or a sanding disc, or a Forstner bit with the nob ground off.

Just wondering (I haven't tried this). Why does the tip need to be ground off - won't it clear the inside of the tube?

[Marvin Hasenak]

I had the bit for for another project, the nob had already been ground off, also the outer cutters, It had been used as a facing bit to square up ends of spindles.

[Art Moore]

Count me in as one who uses a sander instead of a pen mill. I bought a Harbor Freight 1x30 belt sander and a set of transfer punches, and built a dedicated blank squaring station.

[Robert Willing]

https://www.woodcraft.com/products/whiteside-pen-mill-set?gclid=CjwKCAiAsejRBRB3EiwAZft7sCO_2w6PRinFnn-FEmZZaUA24Lw3gh_x4EU6DXF9CgHekKSQL14Q3RoC_6IQAvD_B wE this is an excellent pen mill from Woodcraft. i had both PSI's and the tube fit is better on this mill.

[Rick Gibson]

I gave up on pen mills about 5 years ago when it hit me I was going to need a bunch of different sized shafts for each tube type or turn a barrel to fit my slim shaft and each tube type, plus having to sharpen the mill which I never had much luck at. I took a small thin parting tool I had made with old planer blades and ground the tip to an angle a little less than 60 deg. I cut the blank close to the brass tube then using my turn between center bushings I turn the blank round and a little larger than final size. I then take it out of the bushings and mount it between my 60 deg. live and dead centers. Working on the assumption that the tubes are cut square and the dead center will come to rest on the inside of the tube slightly before the blank is cut even with the tube I take the parting tool I made and place it flat side up on the tool rest and trim the blank slowly to get it square and even with the end of the tube. I trim at the headstock end using a carbide tipped dead center then turn the blank around and trim the other end. While trimming I adjust the tailstock to keep the blank tight against the dead center in the headstock. This has worked well for me through 2 or 3 hundred pens since I started it and since I trim at about 1200 rpm I get nice clean cuts on wood, acrylics and truestone.