Nightmare

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terryf

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Is pretty much what Ive been having the past three weeks.

At first the turning went well, no worries, then about three weeks ago almost everything I turned from wood to acrylic would just blow out.

Obviously segmented was the worst but it even happened sanding at 1200 grit right at the end so it was obviously not just isolated to one action.

I found a couple of guys who have turned pens and picked their brains. The response echoed two problems -

1. My lathe speed is incorrect.
2. Tools are not sharp enough (or incorrectly sharpened)

My lathe runs at 2500 rpm. The tools are clearly a problem and one that is easily fixable.

My questions are hence the following -

1. What speed should my lathe be turning at?
2. What tools are recommended? (HSS/carbide tipped etc)
3. At what angle should tools be sharpened at?

Im currently resorting to sanding the blank down almost completely on the sander and then just rounding the blank on the lathe and then sanding. This works well on softer woods (kiaat)but the minute I go to anything remotely harder it blows out.

Now I must mention that I have turned acrylics with no problem in the past as well as the harder woods like rose/walnut etc

Any and all help would be most appreciated.

Cheers
Terry

Ps. Attached photo of a few of the blow outs - had a total of nine consecutive which I'm sure is some kind of record :frown:
 

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glycerine

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I would say this could have alot to do with how much pressure you are using as well as the angle you are holding your tools. Ride the bevel and lower the tool with light cuts. And yes, they need to stay sharp as well. Do you have a grinder? Are you sharpening your tools?
 

PenMan1

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Terry:
The best pen tool purchases that I have made to date is a Woodchuck Pen Pro and a PSI carbide skew.

The Woodchuck inserts are the sharpest I have found (can be sharpened) and are cheap to replace.

The Benjamin's Best carbide skew is cheap ($21) and I hate cheap tools! But, it is accrate enough when used along with the Woodchuck. When the skew gets dull, I throw it away or give it away and get another. With accurate sharpening systems costing several hundreds of dollars (plus my time of setting it up and using it), I figure I can Toss out about 20 of the $21 skews and still be way ahead.
 
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jttheclockman

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Terry

You have homework. The speed of the lathe is a matter of choice. If you are confortable with that speed that is just fine. The homework is in the tools used. They do need to be sharp but to help you do this you need a jig to hold the tool at the proper angle. The proper angle depends on the tool. What you want to do is use google it is your friend. Google the tool you have and how to sharpen it and you will get alot of hits including videos and utube. It would be virtually impossible to explain it without visual effects. At least I can't but there is so much info on the net other than here that will be of big help. Good luck. By the way you do need to learn the feel of your cutting edges and watch the bits coming off the blank. It will tell you a whole lot of things. Learn to sharpen the tools with the correct angles and learn to use them and by this learn how to present them to the item being turned. That is your homework. :)
 
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jttheclockman

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Hate to disagree with Andy but I read this too often.

I just read the above post and unless you are cutting metals I suggest stay away from carbide tools for turning. Not needed and you will never match the sharp edge you get on a high speed steel tool and that is fact. Sharpening systems do not and I repeat do not cost hundreds of dollars. You can make your own for a couple bucks that will be just as accurate as the manufatured ones. Slow speed grinder is what is needed. Turning pens maybe a small item but the knowledge of using tools and spending on good tools is the same as if you were turning bowls or other larger items. Learn the tools and they will be your friend.
 

terryf

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Thanks for the response so far.

So what Im hearing is buy a set of HSS tools and make a jig to sharpen them instead of sharpening by eye so to speak.

I use a skew and a scraper most of the time so I guess a jig should be pretty easy to make.

As far as google being my friend - yes thats true - but with so many differing opinions out there its difficult to know if the person providing the info actually knows what theyre talking about. Just too easy to pop some info on the web and expect people to take it as fact. I'd rather hear from fellow pen turners than unknown entities.

Can anyone point me to a reputable site re sharpening??
 

robutacion

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Hi terryf,

It can be so many reasons why you are experiencing those problem now...! if you have had successfully turned pens with the equipment you are using at the moment, it is possible that something have changed and you haven't notice it yet, apart from the catastrophic results...!:eek::mad:

Could vibration be the problem...??? is the lathe vibrating or are the bearings still ok...??? these are definitely of good way to get catches with ease.

Were the cuttings tools you are using new from the start, and you got good results until you changed the angles by (poor or lack of sharpening knowledge/equipment)...??? Again, this would be one of the most common problems experience by people with lack of sharpening knowledge, and believe me, most people can't do it right, regardless...! Sharpening jigs are indeed the best solution...!:wink:

These are only 2 of the many possibilities, some of which, other members have already pointed out.

As much as some people hate me mentioning this, the "Flap" discs will get you or any blank, from very soft to very hard, right to the hand sanding stage without failure, 99.99% guaranteed...!:wink::biggrin:

Cheers
George
 

All Thumbs

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Blow outs

One reason not mentioned for blow outs is thightening the mandrel to tight. As the blank gets thinner they will crack and let go. If you are not getting a catch and the blank blows this might be the problem.
 

terryf

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Hi terryf,

It can be so many reasons why you are experiencing those problem now...! if you have had successfully turned pens with the equipment you are using at the moment, it is possible that something have changed and you haven't notice it yet, apart from the catastrophic results...!:eek::mad:

Could vibration be the problem...??? is the lathe vibrating or are the bearings still ok...??? these are definitely of good way to get catches with ease.
I dont believe vibration is the problem. Position of lathe is the same and its about three months old.

Were the cuttings tools you are using new from the start, and you got good results until you changed the angles by (poor or lack of sharpening knowledge/equipment)...??? Again, this would be one of the most common problems experience by people with lack of sharpening knowledge, and believe me, most people can't do it right, regardless...! Sharpening jigs are indeed the best solution...!:wink:

Cutting tools were new from the start and this is where I believe the problem lies. I am going to try sharpening them at 30 degrees and see how it goes.
I think a set of HSS tools and a proper sharpening jig will solve the problem entirely (I hope)

These are only 2 of the many possibilities, some of which, other members have already pointed out.

As much as some people hate me mentioning this, the "Flap" discs will get you or any blank, from very soft to very hard, right to the hand sanding stage without failure, 99.99% guaranteed...!:wink::biggrin:

Currently (so that I dont have to stop turning) I use a very soft wood and use a dics sander to round them to almost bushing diameter and then turn them straight (even so I have the odd blow out)

Cheers
George

Thanks George :biggrin:
 

terryf

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One reason not mentioned for blow outs is thightening the mandrel to tight. As the blank gets thinner they will crack and let go. If you are not getting a catch and the blank blows this might be the problem.

Hmmm, I wonder.........

Very good point, thank you.

In theory though, the bushing is tightened against the tube and therefore shouldn't be putting any pressure on the blank itself but its certainly something to consider.

Thanks again!
 

Grizz

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My first thought was the Mandrel is too tight. After reading comments, I still think that may be the problem. I'd also check, just to do it, if the mandrel is straight and not bent.
 

leestoresund

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I, too, like the Woodchuck Pro and it will do 95% of the job most of the time.
I do like to finish off with a skew.
A "trick" I was taught is that the part of the skew that is ground away should be twice the thickness of the skew.
I've found my turnings much easier since I adopted that rule.

Lee
 

Willee

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Terry, what glue are you using?
The bond between the brass tube and the wood needs to be strong and I do not see any glue on the tubes in your photo of the blowouts. They look bright and shinny.
After looking closely at your photo I think your glue method is the fault.
It looks like the wood is adsorbing what ever glue you are using leaving very little to bond the wood to the brass tube.
Try the polyurethane glue (Gorilla Glue) as it will expand and fill any voids.

I am reasonably sure the glue is your problem but here are some other suggestions ...

Tool pressure, tool angle of attack, sharpness, these could be causing the blowouts also.
It is hard to tell without being there and seeing exactly what you are doing.
When I am cutting wood pen blanks the tool is not held very tightly and the pressure is very light.
I let the tool do the cutting and if I am needing to apply much pressure to get it to cut something is wrong.

I sharpen my HSS skew by hand on a standard grinder and have no problems with it.
You dont need fancy jigs and special slow speed grinders if you understand that a sharp cornered EDGE is what cuts the wood best ... not a knife blade.
I used to spend a lot of time at the grinder trying to get that perfect knife edge until I wised up to the mechanics of cutting wood on a lathe.
Now it takes me less than 60 seconds to touch up the edge of my skew and it cuts wood like butter.

Also check that your brass tubes are flush with the wood you are turning on the mandrel. If the wood sticks out past the brass tube you are stressing the wood with the mandrel nut and that might be causing some of your problem.

All this is offered to help you learn for yourself what you need to know ... it is not offered as a quick fix answer or a sure cure for all your problems.
 
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PenMan1

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I'm don't disagree with JT. It is just a matter of using and maintaining tools. Some people SHOULDN'T use carbide tools. I am one of those that shouldn't use HSS. I tend to apply too much pressure trying to decrease the lathe time. I cut, sand and apply finish as fast as my lathe will run.

Because of forces beyond my control, my shop has recently become a production shop. Additionally, I rarely make wood pens anymore, because I sell many more "alternative" pens.

While HSS tools are great for wood and perhaps casein, they simply are NOT practical for what I do. A pen made with black web tru-stone on top and say soapstone on the other half, can be cut easily with the Woodchuck with one insert. Even a new Sorby HSS right out of the box requires me to stop and sharpen at least twice to complete the task. Additionally, the extra tool pressure that I must apply with HSS increases my "blow out" factor. Additionally, the HSS produces a less smooth surface that increases my finish time.

Because I am now forced to extract my living from what is left over after paying for materials and tools, my goal for the end of each day is to turn out as many high quality pens as possible with the least amount of waste.

The Woodchuck fills this need nicely in that when I need a new sharp edge it is a 15 second stop to turn a screw. In fact, the chuck is useful that when I have to turn wood with HSS, I use the Woodchuck for final passes. The superior, "clean cut" that it produces allows me to skip sanding and move directly to mm.
 
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jttheclockman

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Thanks for the response so far.

So what Im hearing is buy a set of HSS tools and make a jig to sharpen them instead of sharpening by eye so to speak.

I use a skew and a scraper most of the time so I guess a jig should be pretty easy to make.

As far as google being my friend - yes thats true - but with so many differing opinions out there its difficult to know if the person providing the info actually knows what theyre talking about. Just too easy to pop some info on the web and expect people to take it as fact. I'd rather hear from fellow pen turners than unknown entities.

Can anyone point me to a reputable site re sharpening??


Terry

Your last statement is always the biggest problem whenever you ask any question on the net. You will get varying answers just like here in this post. For someone to not use a jig to hold a tool in the proper position every time when sharpening takes a well trained eye. Skews are easy because they are a flat surface unless you are putting an Alan Lancer shape on them. But not all people use skews to turn pens. As far as sites, go to the AAW site and you will get a ton of sharpening and other videos. Pen turning is such a small tiny portion of the world of turning that alot of people do not even consider pen turning a form of turning and you will get arguments from the purist turners on this. You do not actually need a lathe or turning tools to turn a pen. A drill press with sandpaper can also do this.

The key Terry is to learn by either watching someone do it or having an experienced turner show you. Getting answers like this is tough to put into words. By the way you do not even mention the tool or tools you are using to turn your blanks and are you using the same tool for all type blanks???

As far as your blanks blowing up there were and will be alot of good possibilities and only you will be able to come up with the correct answer. But at least you have ideas as to what to look for.

I hope this doesn't come off as a vague answer to your question but it is a hard question to answer and what you are getting is replys of things that each of us ran into but it may not be your answer. Good luck.
 
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Lenny

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Terry, what glue are you using?
The bond between the brass tube and the wood needs to be strong and I do not see any glue on the tubes in your photo of the blowouts. They look bright and shinny.
After looking closely at your photo I think your glue method is the fault.
It looks like the wood is adsorbing what ever glue you are using leaving very little to bond the wood to the brass tube.
Try the polyurethane glue (Gorilla Glue) as it will expand and fill any voids.

Willie beat me to it. I agree! The other things mentioned could also have been factors but I believe if you are using CA glue to glue your tubes in THAT is where you look first when experiencing blow outs! Gorrilla brand polyurethane glue OR 5 min. epoxy would give a better bond and one that isn't effected by the heat generated from turning. my $.02 :)
 

randyrls

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Terry, what glue are you using?
The bond between the brass tube and the wood needs to be strong and I do not see any glue on the tubes in your photo of the blowouts. They look bright and shinny.
After looking closely at your photo I think your glue method is the fault.
It looks like the wood is adsorbing what ever glue you are using leaving very little to bond the wood to the brass tube.
Try the polyurethane glue (Gorilla Glue) as it will expand and fill any voids.


I will add to what Willee said. Brass tubes are coated with lacquer to prevent tarnish. Always rough up the brass tubes with sandpaper to remove the lacquer and allow the glue to adhere well to the tube.

Make sure you are using enough glue! Use playDoh, a potato slice, or dental wax to block the end of the tube you insert into the blank.

There is a page in the Wiki with this information:
http://www.penturners.org/wiki/Pen_Blank_Preparation
 

terryf

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Pen blank prep is not the problem

I use epoxy glue, I do roughen the surface and square before placing on the mandrel.

I fit the mandrel to the lathe and then tighten the nut.
 

tim self

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IMO, looking at your blowouts, I suspect simply not having sharp tools and applying to much pressure on the blanks to achieve the cut. Find the best way for you to sharpen and practice that first.
 

PenMan1

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Pen blank prep is not the problem

I use epoxy glue, I do roughen the surface and square before placing on the mandrel.

I fit the mandrel to the lathe and then tighten the nut.

Then the problem does sound like dull tools...or tools with the wrong edge...or applying too much pressure to the tool.
 

rjwolfe3

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While I do agree with the above about sharp tools, sometimes wood just blows out. Could just be crappy wood. I know that you also blew out acrylic too so I vote for sharper tools.
 

terryf

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My immediate thought was that there's no glue on the tubes, so I agree with Lenny and Willee that you're gluing technique needs consideration...

well I apply an epoxy glue liberally around 4/5 of the length of the tube and then insert it into the blank and turn whilst pushing.

heres some enlargements of the first pics - cropped to show close-ups of the tubes. In the one pic you can actually see how Ive turned the tube when inserting.

if Im doing it incorrectly or there is a better method, please feel free to correct me.
 

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glycerine

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Terry, if you have a bench grinder, check out the Wolverine sharpening system, or make one like it. I made one that's very similar and used JB-Weld to hold it all together: http://www.penturners.org/forum/showthread.php?t=65717
It works very well for scrapers, skews and roughing gouges. I haven't built a jig for "fingernail" gouges yet, but I have sharpened all of the others I just mentioned... As far as sharpening, I have seen some good videos on youtube. One guy I like is Cap'n Eddie Castelin. He has alot of good information.
 

sbwertz

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Looking at the wood blank that blew out, were you turning cross-grain? 99% of the time if I get a blowout it is when I am turning cross-grain wood. Certain open grain woods are almost impossible to turn cross grain. (That doesn't address the acrylic problem, I know.) The very first time I tried making segmented blanks I used wenge and lauan....both very open grain woods, and they were cross grain to maximize figure. Blew out EVERY TIME I tried to turn one. A good hard heartwood blank usually turns fine crossgrain for me. Turning crossgrain you have to have your tools razor sharp, as well.

I, too, use the Wolverine system with a low-speed grinder (1750 rpm). I went to the local Woodcraft store and took a sharpening class to learn to use it, but it came with a dvd that is pretty good.

Sharon
 
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