What's the trick to using carbide?

[MiteyF]

I'm a HSS guy through and through, but bought a Magical Skew a few months ago specifically for turning plastic (I hate turning plastic) blanks. I had to TIG weld a new tool rest for my lathe, as neither of my other 2 would go low enough for the MS. I've used it about a dozen times, but can't for the life of me get the hang of it. It seems unless I'm SUPER careful, the thing will catch like crazy, and even when I AM super careful, it'll still catch. I've tried the round cutter, square cutter, cutting at the centerline of the work piece, cutting below the center (more like a scraper), different angles every which way, everything I can think of, and still it's a royal PITA. Then to make things worse, there's no way to make a nice even, flowing cut. You can't ride the bevel like a "real" turning tool, so it seems to me you have far less ability to get the nice, subtle curves most of us look for on a barrel. Especially with the round cutter. I can't fathom how or why anyone would use one of these things on a pen!

Now, before you say "so just go back to HSS and throw the carbide in the toolbox", here's the issue. I've got a blank I bought specifically for my mother (xmas gift) that's small sea shells encased in resin. Because the shells are so hard, I kind of need to use the carbide so I don't completely trash my go-to HSS tools. Add to that the fact that I believe it's a limited run, and the and I really can't afford a nasty catch on this one.

I just turned an acrylic pen earlier today with the MS to try and get in a bit more practice before I start on this special blank, and was barely able to finish... catch after catch, and it's almost impossible to get a nice even finish without ridges because of the shape of the cutters and the way the thing grabs the tool rest (my tool rest is ground and polished stainless steel, smoother than a baby's bottom, a chunky rest isn't the problem here!)

Does anyone have any good tips for me on how to make this work so I don't ruin this blank? I swear it was easier for me to learn to use an actual skew chisel than it has been for me to try and figure out this stupid carbide business.

Thanks in advance (my mother will thank you too!)

 

[RKB]

First I Hope your Mom's Pen comes out GREAT. I use carbide with success, the one thing I would mention would be to check the bottom of the carbide tool and make sure the screw holding the cutter is not protruding through the tool. This will cause the carbide tool to jump. I have had that happen with replacement screws. Merry Christmas.


Rod

 

[rholiday]

The magic skew is used with the handle horizontal to the floor, the cutter at the center line. There is a flat on the underside of the tool that will keep the cutter at the appropriate angle to the work, (close to 45 degrees, but I did not check it). I use my standard tool rests without modification.

Bob

 

[MiteyF]

RKB, the screw doesn't extend through the tool, good idea though.

Holiday, the tool sits 30* from horizontal. If you look at the shaft, it's just hex bar stock with flat milled where one of the 60* angles would be, hence the 30*. That's why I bought the MS as opposed to a round shafted tool, to sort of ease me into using carbide. Seems it hasn't worked out like I'd hoped. Again, not blaming the rest, I'm assuming it's a loose nut between the tool and the workpiece. Just hoping someone can tell me how to tighten it

 

[mark james]

I have been using the "Magical Skew" since it was a prototype (lucky me). I have been using it more and more the past six months, with great success. A learning curve, sure. I have three bars, made my own handles, so I have three profiles. I find that each has its purpose.

I also use HSS gouges, Sorby spindlemaster, Easy Wood Tools, and another 5-8 misc tools. All are useful.

I'll simply say that every tool will have a learning curve and be useful. AND, many tools will accomplish the same end result, so get comfortable with what works for you.

Finally, I'll also say that for the past 6 years I go back to the traditional HSS skew and practice, and practice... Poor results. I have NO SKILL for the traditional skew - but in a few months I'll try again.

So, as Winny said: "Be Calm And Carry On." Everyone will have their favored "bag of tools."

 

[Magicbob]

Sorry to hear you are having trouble "learning" the Magical Skew.
On embedded objects in plastics I recommend you set the center of the cutter slightly above center, be sure you anchor the tool on the flat of the hex bar and move it in the direction the cutter is facing.
The tool should be parallel to the floor, and and square with the blank.
Take very light cuts.

 

[MiteyF]

Bob, my concern with using it above center (especially with this blank) is that with the astounding frequency I'm getting catches, and the fact that there are shells in this blank (very brittle), it seems very likely I'll end up with a destroyed blank.

Light cuts seem to be the way to go (like you say). But with these damn plastic blanks, the cut material just wraps around the blank, and there's no way to see where your tool is traveling. With a traditional tool you'd simply use the bevel and "feel" your way through the pass, but since there's no bevel on carbide, you're kind of running on a prayer. And I've found it to be incredibly difficult to pick back up on a cut with carbide compared to HSS, which makes me hesitant to "pull out" of the cut before I reach the end of the blank.

If I'm using the square cutter (still don't understand using a round cutter for pens, makes no sense to me!) where on the carbide should I be contacting the blank? Just "below" the center? Nearer the leading edge/corner? Might a change in yaw of the tool help me in any way?

I'm sure once you figure the thing out, it would be a marvelous tool. I just can't!

 

[stonepecker]

One thing I 'learned' the time I had to work with the MS was that you are not "Cutting" with the complete carbide cutter. First, a round cutter has no points to catch with. Yes, it leaves a "wavey" finish which means I had to sand more. Second, When you use a R2 cutter......stay away from the points. You just use the "center" of the carbide to cut. It is the points of the cutter that catch. At least that is what I found happens to me.

Yes, there is a learning curve......like with any tool. But, in my opinion, the MS used with light cuts.....level on the bevel of the bar.....and by taking things slow.....is the easiest way to learn how to use carbide tools. It is just a beginning. The skill comes from doing it right, over and over ….. again and again.

I wish you the very best with your mother's pen.

 

[bsshog40]

I'm sure you've probably seen this video of a guy using the round cutter. Just in case you haven't.
https://video.search.yahoo.com/search/video;_ylt=A0geKeQoPv9bjOsAvAdXNyoA;_ylu=X3oDMTE0bWltYTRqBGNvbG8DYmYxBHBvcwMxBHZ0aWQDQjQ4NTNfMQRzZWMDcGl2cw--?p=magical+skew+wood+turning&fr2=piv-web&fr=yfp-t-strm013%2CFPTR003%2CFPYVID01#action=view&id=1&vid=a43d55049ab477e36d1b9e88591f1d10

 

[PenPal]

I have success only when I use the square chisel just below centre as when I use the Skew on the flat.

Peter.

 

[leehljp]

Im curious about something. What speed are you turning?

 

[mark james]

there are shells in this blank (very brittle), it seems very likely I'll end up with a destroyed blank.

I suspect your issue is with the material, not the tool.

I bought several blanks with imbedded shells. They were supposed to turn out beautifully, If I could sacrifice several carbide cutters, be willing to ruin several blanks to get the hang of the material, and basically, waste a lot of resources for a severe learning curve; I gave the blanks away!

If you are turning the material I suspect, it will be beautiful if successful, but a very advanced blank. I do believe the issue is the material not the tool.

 

[magpens]

Well, MiteyF, how about this for advice:

"The beauty of being a consumer is that you get the final say. Buy something else.
Suddenly it's not a problem any more."

Sound familiar ? ... try it ! :biggrin::biggrin::biggrin:

 

[mecompco]

I've not touched my HSS tools since I got the MS. I use the R2 cutter--MUCH for forgiving than a square cutter and in my hands, leaves a much smoother finish than does the round cutter. I like my edge slightly above center, and when using as a "skew", I prefer to raise the handle rather than keep the tool horizontal as I do when I scrape with it flat on the rest (which I'd probably avoid with a blank with embedded items).

 

[robutacion]

G'day,

I was also wondering about the fact that turning speeds were never mentioned I would think faster would be better than slow, however, you have only 1 expensive blank so no much of a chance for practising so, I could not pass the opportunity to suggest you use the "Flap disc system", I know you've got a carbide tool especially to deal with this blanks but hey, you can practise with this new tool on other blanks and instead use a system that I will guarantee you will succeed a lot easier than you ever thought.

Take a good look at my pics and instructions, you have all the answers in there, it's your decision, your choice...!

Best of luck

Cheers
George

 

[Sylvanite]

Catches are usually the result of insufficient axial pressure, which allows the chisel to pivot and dig into the work. Pushing lightly into the piece, but firmly to the side should eliminate most catches.

I hope that helps
Eric

 

[JimB]

Why do you think you will trash your HSS tools on the blank? You will need to do more sharpening but you will not trash them. Go back to what you are comfortable with.

 

[Edgar]

I second the "use the tools you are most familiar with" on a special blank where you can't afford mistakes.

As far as carbides, I use a mini-EWT R2 for pens. It doesn't have the natural angles of the MS, but I have no problem simply canting the tool to a 30-45 deg angle. For wood blanks, I go straight in to get the diameter close to final size, then use canted cuts as I move the tool along the tool rest. For plastic, I use the canted cuts for the entire process. Sometimes I knock off the corners on a sander, especially on expensive blanks.

As done have mentioned, speed is important. I turn about 2500-2800 RPM, some turn even faster. High speed is good for any pen blank work, but especially for plastics & carbide tools.

I keep a couple of old toothbrushes handy to quickly remove the plastic ribbons that wrap around the blank & shaft.

You didn't say what type of tool rest you have. The Rick Herrell flat-top rests are ideal for carbide tools. They give more surface area for the tool to sit on and make it easier (at least for me) to keep the to stable & avoid catches. I like them so much that I have 4 of them in various lengths and use them almost exclusively, no matter what tool I'm using.

Keep practicing & experimenting, you'll develop techniques that work for you.

 

[walshjp17]

I have been using the MS for about three years now. It is my go-to tool for pen turning. When I turn a pen, I set my speed about 3500 RPM (+ or -) and set the tool rest so the cutter is in the middle of the blank. I have experienced no problems with the MS whether shaping wood, acrylics or other materials. I use both the round and R2 cutters.

<RANT> That said, I will never do another sea shell blank. I went through the MS, EWT's regular and negative rake cutters and almost 1/2 bottle of CA glue on one blank! A pox on the sea shell (and cherry pit) blanks. Phooey!! <RANT OVER>

Bottom line: Best tool I have ever used for pens.

 

[MiteyF]

Thanks for all the suggestions guys.

Bobby, I don't know that I've seen that video before. He certainly seems to have a far better grasp on the tool than I! Although if I tried to turn with the MS and that enormous gap between the rest and the blank, I think I'd be in a world of hurt!

As for speed, I've tried the carbide all over the place, from about 1k up to 3k. Once my blanks are round, I'm usually around 2500ish (slower with HSS and plastic blanks).

Mark, "a craftsman never blames his tools". I'm no craftsman, but I've always made due with the tools I have available. As I've stated before, I'm quite confident the problem here is not the MS, it's the big fleshy sack holding it! It's a shame you never tried the blanks, some first hand knowledge would be killer here! I don't mind ruining a carbide or 2 for a good result. I just can't afford to ruin a few blanks!

Mag, good advice that! I've no issue with the tool though, just an issue with my technique. Can't pop in to the local Woodcraft for one of those though!

Michael, that scraping technique has been the "safest" for me too as far as catches go. Not as nice as a finish though it seems. I may have to resort to this for this blank.

George, I've got many of those exact same sanding/grinding tools in the shop (angle grinder, air grinder with 2"-ish grinder foot, right angle drill), and if all else fails perhaps I'll give that a go. My experience with angle grinders/air grinders/flap wheels etc is that they're not usually terribly precise and can be difficult to to get a smooth contour, but that's certainly a novel idea that I'd have never dreamt of myself. If I don't try it on this blank I'll certainly store it back in the ol' noggin for future use.

I all else fails I'll go back to my HSS. I've had my Worksharp apart twice in the last 2 days, something going wonky inside. Not a good time to lose your sharpening system.

Edgar, the rest I usually use is 5/8" stainless, turned and polished round stock that I welded myself, and polish to about 3k grit on my Worksharp. Nice and hard and tools slide beautifully on it. I've never heard of or even considered flat tool rests, but maybe I'll poke around the scrap bin and weld one up today to see if it helps. It seems like that would cause extra drag and make it even more difficult to get a smooth contour, but obviously my pre-conceived ideas up to this point haven't helped much, so there's that...

Thanks again guys for all the help. With any luck I'll be out in the shop today and give this thing a quick go.

 

[MiteyF]

John, I've only ever heard good things about the MS. Just can't seem to work it myself. I'm sure this blank will be challenging, and I've already figured that I'd need to do a LOT of filling holes, just from what I've seen after drilling and gluing in the tubes. I've finished my other pens for the time being and have accepted that this blank may end up sitting on the lathe for a few days while I fill holes, adjust my technique, and drink beer while staring at it.

At least you've done one, so I know it's possible!

 

[Paul in OKC]

I agree with use what you are comfortable with/like. As a machinist for 40+ years I use carbide tools all day long.....on steel. I have made my own carbide cutters years beofre they were popular. They still sit unused for the most part because I get better results with HSS. Now that being said, I use a 1/4x1/2x6" pice of HSS, rounded on the end with about a 15-20 degree rake, flat on top. Been my tool of choice for years. Every one has their preferences and that's what makes this a good place for info. Nobody here, at least in my experience, is here to tell you that there is only one way to do something. Good luck! YMMV

 

[RobS]

I second the use of the Rick Herrell tool rest (shown in photo below, with the length about the length of a bushing longer on each side), its been a god send for me, I own 5 in different length. You need that nice flat consistent surface. Master the small round first, then work your way up to using the square and practice when the blank is still fat, that way when you dig too deep you have time to learn and correct before the blank gets to size. I usually use the diamond tip to rough it down to round, then the circular to get it close, then I clean up with the small square.


View in Gallery

You didn't say what type of tool rest you have. The Rick Herrell flat-top rests are ideal for carbide tools. They give more surface area for the tool to sit on and make it easier (at least for me) to keep the to stable & avoid catches. I like them so much that I have 4 of them in various lengths and use them almost exclusively, no matter what tool I'm using.

Keep practicing & experimenting, you'll develop techniques that work for you.

 

[mredburn]

Are you turning between centers or on a mandrel? You may have better luck turning between centers, the mandrel could be deflectiing and aid in causing the problem of catching.

 

[MiteyF]

I've tried both between centers and with the mandrel. Even when I use the mandrel though, I use a collet chuck on my headstock, I do one tube at a time and use a mandrel saver in my tailstock, so it's quite stiff, not much deflection at all. I've even tried the carbide with a big chunk of delrin between centers (made a new anchor roller for a family member's boat) and was getting nasty catches there too.

 

[stonepecker]

I know that this will sound to simple...….but have you tried a 'new' cutter?

 

[MiteyF]

I've tried both the round and "square" cutter that came with the tool, even using "fresh" sections of the cutter, no luck.

Paul, any chance you've got a picture of your go-to homemade tool? I've got some HSS laying around, as well as a good grinding/sharpening setup, and would love to make one to try.

Rob, thanks for the pic. Time to dig through the scrap metal and see what I've got.

 

[JimB]

Are you trying to learn on plastic blanks? If you are try turning wood to learn. I don't know what you have in your area but if you were around here I would tell you to use a piece of cherry.

 

[MiteyF]

I bought the carbide specifically for plastic and hybrid blanks. I've used it a few times on wood, but wood cuts so differently than plastic I didn't see much sense in spending a whole lot of time making dust. I've used it about a dozen times (mostly plastic) and it just doesn't want to work with me for some reason.

 

[JimB]

I bought the carbide specifically for plastic and hybrid blanks. I've used it a few times on wood, but wood cuts so differently than plastic I didn't see much sense in spending a whole lot of time making dust. I've used it about a dozen times (mostly plastic) and it just doesn't want to work with me for some reason.

IMO, that could be part of the problem. When you are learning to use a new tool it should be on easy to turn material. Once you understand how the tool works then move on to the plastics. I have taught many people to turn, both new Turners and people who have been turning for a while but want to start using a different tool. I ALWAYS start them on a wood that is easy to turn such as Cherry. Once they understand the tool and how to use it they move on to more difficult Woods.

You also point out you can't see what the tool is doing due to the ribbons coming off the plastic and that is part of the problem. Starting with wood will allow you to see, feel and hear what the tool is doing. Once you can feel and hear what it is doing you won't need to see through the ribbons of plastic.

Another problem might be the type of plastic. Some plastics turn much easier then other plastics. You might be trying to learn on a very difficult to turn plastic.

 

[TonyL]

My silly opinion:

The trick is finding the right combination of tools, techniques, pressure, grips, cutting angle, lathe height, rpms, etc. AND then coming to a balance of effort, patient and finish that you what to achieve. In this way, turning will be fun and you will be please with your work.

You sound very committed. I believe you will not take you long. I am not half as gifted as many of the members; I enjoy what I do. And I love the comradery of this forum.

Happy turning and enjoy the journey!

 

[MiteyF]

Thank you for the vote of inspiration Tony.

So I bit the bullet and chucked up one of the tubes. I went slooooooooow, and only managed a minor catch or 2. The shells are so hard that the blank just spun on the mandrel. I did eject 2 or 3 shells at mach 12 though. I'm going to burn through a lot of glue with this one. I didn't even get the thing round before one brand new face of my square (radius'd) cutter was as too dull to cut.

Just to be sure, I also gave it a go with my absolute favorite, go-to turning tool, a 3/8" Sorby gouge. The shells were so hard, that even with a VERY sharp tool, the gouge didn't even touch it, just dulled up my nice edge.

Who can recommend a decent carbide insert that isn't terribly expensive? I think I'll probably kill 2 or 3 on this pen. I'd hate to spend $24 on carbide, only to throw it all away in another day or 2. But if there isn't anything less expensive, so be it. (Also, hopefully from a retailer who won't dilly dally with shipping, as this is supposed to be a xmas gift after all.) There's a 10-pack on Amazon for about $25, I can't imagine they're stellar for that price though.

 

[Paul in OKC]

Here's my tool. I just rounded the edges enough to go in the 1/2" hole in my handle. As far as carbide, I believe most wood turning inserts are pretty well 'raked' underneath. May make the edge weak for the application. The ones I have have a 7 degree rake. Not sure if that would be better, just a thought.

 

[KLJ]

My son made a pen out of cold rolled steel, he only used sandpaper and file on a wood lathe. It took a lot of patience but turned out very nice, maybe something to try once you get the corners off. Hope it turns out well for you.

 

[TonyL]

Who can recommend a decent carbide insert that isn't terribly expensive?

When I used carbide, I found AZ Carbide to be reasonably priced. They are also one of our vendors and good people.

https://azcarbide.com/

 

[JUICEDSS]

Ever since I started using the easy wood tools negative rake cutters my issues have gone away. I find they cut through very well and I haven't had a catch in the last 75 pens or so.

This thread has some info: https://www.penturners.org/forum/f14/ewt-negative-rake-cutters-156928/

 

[Edgar]

I get my carbide cutters from Captain Eddie

Big Guy Productions -  

 

[hanau]

Which insert you looking for?
square insert or round insert?

 

[MiteyF]

Square radius I think

 

[MiteyF]

Thank you to everyone who offered advice. This was by far the most challenging blank I've turned. I went through 2 1/2 square cutters getting this thing done (10 edges!), but it survived. I bought what I *thought* was the same pen kit I've turned a half dozen times and very much like (classic rollerball), but from a different source. Turns out, it's a different, *much* lower quality kit. Too late now. It will have to suffice.

Thanks again for all of the advice. Sorry for the quick snapshot, time to get packed up and leave for holidays with the family, no time to set up the "photo booth".