Blank end mill question

[crazylegs]

How do you all sharpen the cutting part on the pen mill? The thing you use to get the ends of the blanks square.

 

[Phil Dart]

How may blades on your mill?

 

[Neil]

How do you all sharpen the cutting part on the pen mill? The thing you use to get the ends of the blanks square.

The bin, shocking things, they weaken the end of the blank, ripping the fibres. Only ever use with man made materials.

 

[Penpal]

Tried most all of the penmills and only use a dedicated disk sander with two sets ie Imperial and Metric punch sets as mandrels and an absolute accurate hand made holder with a most suitable drill chuck from a hammer drill (new one) they have long holding jaws.

Peter.

 

[crazylegs]

Tried most all of the penmills and only use a dedicated disk sander with two sets ie Imperial and Metric punch sets as mandrels and an absolute accurate hand made holder with a most suitable drill chuck from a hammer drill (new one) they have long holding jaws.

Peter.

Do yuo have a picture of the set up?

 

[Curly]

Disc sander here too. A little simpler than my southern namesake.

Pete

 

[Phil Dart]

How may blades on your mill?

You've had plenty of answers telling you how dreadful pen mills are. My own opinion is that they are not dreadful, they are actually bloody fantastic, as long as they're sharp. Most people don't sharpen them so consequently they consider them dreadful. The method of sharpening will depend on how many blades yours has, so I ask again, how many blades does yours have please?

 

[wm460]

Heres my little pen sander.

 

[crazylegs]

I have one with 4 blades and one with 6 blades.

 

[crazylegs]

what is the bar with the blank on?

 

[Curly]

what is the bar with the blank on?

That is a transfer punch or pen disassembly tool, depending on where you buy from. Peter posted 2 sets and my jig only showed the one I last used but it can be changed out to fit any blank you are working with. You could use a drill bit in a pinch if you needed to.

Pete

 

[fortress]

Hi Kevin,
I Myself never use a pen mill on wood only acrylics, on wood I use a set up like others have shown with a sanding disc.

 

[Phil Dart]

I have one with 4 blades and one with 6 blades.

The one with 6 blades is next to impossible to sharpen accurately. The only thing you can do is put a diamond card across the face of the blade, and hope that card is held at the same angle with every pass. These 6 blade versions come from China and are another reason why pen mills get a bad name.

The 4 blade versions are easy to sharpen, and there are two methods.
Lay a diamond card flat in the edge of your workbench and pass the back of the blade along the card. You're not sharpening the face, you're re-setting the cutting point by refreshing the back, much the same as sharpening a carbide cutter.
The other method is to sharpen the face, but because it only has 4 blades, it's easy to make a jig so that the angle is the same each time. I have a homemade jig that fits on my ProEdge, and it takes about 20 seconds to sharpen the whole thing.

I realise this is contentious, but in my humble opinion, a sharp, well maintained pen mill will give a better, faster and more accurate result over a disk sanding method every time.

Other opinions are available.

 

[crazylegs]

Thanks Phil. I have found them to work well in the past but only when sharp. I will try the diamond card method. Any chance of a picture of you proedge jig?

 

[Phil Dart]

Yep, I'll have to dig it out. I moved recently and it'll still be in a box in my chaotic workshop.

 

[crazylegs]

strange but no matter how often tidy I always have chaos.

 

[howsitwork?]

I would use a diamond lap and rub carefully only on the flat size of the blades until you get a very small burr detectable with a fingernail at the cutting edge . This should just knock off and you’re sharp.

Must admit I like the look of peters sanding system ( both Peter’s versions) but with a gentle touch and sharp cutters I’ve not had a major issue generally.

 

[Neil]

Hi Kevin,
I Myself never use a pen mill on wood only acrylics, on wood I use a set up like others have shown with a sanding disc.

Snap.......

 

[Pierre]

I only have 4 bladed ones and I use a small engineers flat fine file to sharpen them.

I don't agree that they ruin end grain, as a trained cabinet maker I use a scraper on end grain very successfully especially when passing over dovetail joints, you have no option and blunt doesn't 'cut it' pun intended. (its the same principle) and so long as you have about a 15 degree burr on the cutting side then it should cut properly, part of the technique is not to push the blade too heavily and let the tool cut and pull, also don't leave too much excess wood from the end of the tube to the start of the wood to cut. I try to get my blanks to 1-2 mm longer than the tube. BUT that is after drilling where the wood is longer because many woods like Thuya burl, wisteria, grape vine and even Oak etc will have blow out as the drill cuts its final stages, so just lop the scruffy bit off and mill to your heart's content.

The same applies to scrapers, when you sharpen them make sure you create a 15-25 degree burr (depending on whether you use a pro-edge or not) and dont knock it off on the honing wheel you will be able to create issue thin shavings instead of dust.

Also the mills as supplied are probably not really sharp in the beginning so sharpen them first.

 

[21William]

There is also this way of doing it.

OFFSET LATHE SANDING JIG

This tool... - Custom Made Penturning Tools | Facebook

Although I have a well equipped shop I think it’s a good idea if folks can do stuff with the equipment they already have ie the Lathe! Like others I’m not a fan of barrel trimmers, just another gadget that’s not really needed. We all have sandpaper don’t we?!