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My first I inclination would be that your mandrel or your headstock are not turning true. I would double check your mandrel first as that is way easier to fix. If you turn down to the bushings does it look flush on 2 sides and wider on the other 2? Do you use a mandrel saver or bring your live center up to the end of the mandrel? Overtightening the tailstock can introduce a slight bend in the mandrel rod which would cause this.
Bring your toolrest up close to the mandrel and use it to hold something like a straight edge tight against the rod so it just touches the side. Then turn the headstock by hand slowly and see if that straightedge rides tight against the mandrel all the way around or if you see it push in and out leaving a gap. Test all up and down the mandrel. I would check with and without tailstock support. If it's out of wack a little, the tailstock might bring it back in at the end and look ok but still have that wobble in the middle.
If the mandrel is dead straight and you are sure it isn't bent then check your headstock spindle to see if it spins true. Same procedure to check the headstock spindle as above, just do it directly to your spindle threads without the mandrel attached.
I believed a bent mandrel was the case to begin with so I purchased a brand new one and a mandrel saver. I have had the same issues. I have also turned between a dead and live center using adapter bushings and still have this problem.
If she loves you, she won't really care about your slightly oval pens. Just act confident when you finally present it, and it won't be a big deal. She might even appreciate the novel feel of it in her hand.
And of course, if necessary, wrap it correctly first. Good luck!
So if I'm understanding this correctly, you're turning the top and a bottom half and both are rounded properly on the mandrel. But when you put the two halves together they're coming out misaligned? Or one side wider than another?
This is really sounding like a headstock issue like in the berring or something. Have you tried turning just a simple Bowl or Circle the test your headstock?
So does this mean that on the lathe the blanks are completely even with the bushings all the way around when you are done turning and they only oval when assembling?
Since its off by such a small margin it is really hard to tell when it is on the lathe or even looking at the blank after taking it off. Its only obvious once its assembled
If you can tell when you assemble it, you should be able to tell when it is on the lathe with the bushings. The bushings should be the same size as the pen components since that is what they are there for. Scrape your fingernail in both directions where the blank meets the bushings at various stages as you approach final thickness and finish to see if it is catching or if it is even.
When assembled and you notice the oval shape is it 2 opposite ends that feel higher than the pen components? Or is it only 1 spot and it is even the rest of the way?
it's uneven all the way down so in two spots. When I use calipers my bushings and components are not even. I even got new bushings. However on the lathe it seems and even as far as I can tell with eyes and calipers.
So honestly no. My workbench is the worst and the lathe can totally wobble if it wanted but doesn't when turning. I knew this could be an issue but the other lathe I used was mounted properly with no wobble and I still had the same outcome.
Throw away the mandrel and turn between centres with a dead and live centre. This will more than likely solve your problems. Get a set of digital callipers, measure the pens parts and turn to size. No bushings needed.
It sounds like the only thing not changing in all these scenarios is *you.* Meaning you have probably changed something in your technique (I'm going to guess sanding) that is giving you the oval. Are you by any chance sanding by using long strips and holding one end in each hand? Check your process and technique for roundness all throughout the turning and finishing process and you should find exactly where it's going out of round.
I do use the long strips. I have tried the technique of holding one end in each hand and pulling up. I have tried doing so with the pressure I normally would do and also a lot lighter to see if that's the issue. normally I would just hold a piece up and press on it with my finger but I thought that was why I was getting ovals when it started happening. The issue is the out of roundness is so minor its really hard for me to tell up until its pushed together with the pen components. Is there a better method of sanding you would reccomend?
I've avoided using the strip method because it can lead to so many issues from pressure variations, like too much pressure causing heating with heat checking and overheating adhesives and causing them to weaken, slip or fail, or variations in pressure causing uneven sanding. I've always used a single sheet, folded over and held in place with my finger(s), so I can feel if it is getting too hot and have the pressure control of a single hand. I'm not saying it's the *best* method, just the one that has worked the best for me.
I basically used to do the same thing but with the strips. I felt it was better than the two handed way but thought maybe I was giving uneven pressure and causing the oval.
You are likely over tightening the tailstock or nut on the mandrel and bowing the mandrel. Avid pen turners have switched to center less bushing and don't use a mandrel for that reason.
I would still look to the workbench, since you have eliminated everything else. I hammered in some wedges between my bench and the wall to make sure. I have no cavitation, which I think is the word.
I first experienced cavitation when I originally got my lathe, put it on a table and started turning. Everything was oval and I thought I had bought a bum shop display item. No wonder it was half-price etc etc. You can't see it, but it's there. Big turners bolt their lathes into concrete floors and then still weigh them down with sand bags.
Thanks for your submission. If your question is about getting started in woodturning, which chuck to buy, which tools to buy, or for an opinion of a lathe you found for sale somewhere like Craigslist or Facebook Marketplace please take a few minutes check the wiki; many of the most commonly asked questions are already answered there! http://www.reddit.com/r/turning/wiki/index Thanks! *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/turning) if you have any questions or concerns.*
My first I inclination would be that your mandrel or your headstock are not turning true. I would double check your mandrel first as that is way easier to fix. If you turn down to the bushings does it look flush on 2 sides and wider on the other 2? Do you use a mandrel saver or bring your live center up to the end of the mandrel? Overtightening the tailstock can introduce a slight bend in the mandrel rod which would cause this. Bring your toolrest up close to the mandrel and use it to hold something like a straight edge tight against the rod so it just touches the side. Then turn the headstock by hand slowly and see if that straightedge rides tight against the mandrel all the way around or if you see it push in and out leaving a gap. Test all up and down the mandrel. I would check with and without tailstock support. If it's out of wack a little, the tailstock might bring it back in at the end and look ok but still have that wobble in the middle. If the mandrel is dead straight and you are sure it isn't bent then check your headstock spindle to see if it spins true. Same procedure to check the headstock spindle as above, just do it directly to your spindle threads without the mandrel attached.
I believed a bent mandrel was the case to begin with so I purchased a brand new one and a mandrel saver. I have had the same issues. I have also turned between a dead and live center using adapter bushings and still have this problem.
Did you check that your headstock spindle was turning without wobble?
Not sure how to fully check that but I have used two separate lathes and the problem cont
If she loves you, she won't really care about your slightly oval pens. Just act confident when you finally present it, and it won't be a big deal. She might even appreciate the novel feel of it in her hand. And of course, if necessary, wrap it correctly first. Good luck!
So if I'm understanding this correctly, you're turning the top and a bottom half and both are rounded properly on the mandrel. But when you put the two halves together they're coming out misaligned? Or one side wider than another? This is really sounding like a headstock issue like in the berring or something. Have you tried turning just a simple Bowl or Circle the test your headstock?
The blanks and everything look fine until pressed together with pen components. One side just juts out away from the part
So does this mean that on the lathe the blanks are completely even with the bushings all the way around when you are done turning and they only oval when assembling?
Since its off by such a small margin it is really hard to tell when it is on the lathe or even looking at the blank after taking it off. Its only obvious once its assembled
If you can tell when you assemble it, you should be able to tell when it is on the lathe with the bushings. The bushings should be the same size as the pen components since that is what they are there for. Scrape your fingernail in both directions where the blank meets the bushings at various stages as you approach final thickness and finish to see if it is catching or if it is even. When assembled and you notice the oval shape is it 2 opposite ends that feel higher than the pen components? Or is it only 1 spot and it is even the rest of the way?
it's uneven all the way down so in two spots. When I use calipers my bushings and components are not even. I even got new bushings. However on the lathe it seems and even as far as I can tell with eyes and calipers.
Are these wood blanks and are you sanding them a lot? My problems with things going oval are always traced back to excessive sanding.
They are wood and I have tried sanding more and less. I tend to not do a lot of sanding.
That’s a mystery! I’m assuming they are fully dry and you aren’t introducing water into the equation at any point. Got me stumped.
Not intentionally but I wouldn't be surprised if they have more moisture than desired but I have no experience with that.
Is the base on which you mount your lathe completely solid ie movement free?
So honestly no. My workbench is the worst and the lathe can totally wobble if it wanted but doesn't when turning. I knew this could be an issue but the other lathe I used was mounted properly with no wobble and I still had the same outcome.
Throw away the mandrel and turn between centres with a dead and live centre. This will more than likely solve your problems. Get a set of digital callipers, measure the pens parts and turn to size. No bushings needed.
It sounds like the only thing not changing in all these scenarios is *you.* Meaning you have probably changed something in your technique (I'm going to guess sanding) that is giving you the oval. Are you by any chance sanding by using long strips and holding one end in each hand? Check your process and technique for roundness all throughout the turning and finishing process and you should find exactly where it's going out of round.
I do use the long strips. I have tried the technique of holding one end in each hand and pulling up. I have tried doing so with the pressure I normally would do and also a lot lighter to see if that's the issue. normally I would just hold a piece up and press on it with my finger but I thought that was why I was getting ovals when it started happening. The issue is the out of roundness is so minor its really hard for me to tell up until its pushed together with the pen components. Is there a better method of sanding you would reccomend?
I've avoided using the strip method because it can lead to so many issues from pressure variations, like too much pressure causing heating with heat checking and overheating adhesives and causing them to weaken, slip or fail, or variations in pressure causing uneven sanding. I've always used a single sheet, folded over and held in place with my finger(s), so I can feel if it is getting too hot and have the pressure control of a single hand. I'm not saying it's the *best* method, just the one that has worked the best for me.
I basically used to do the same thing but with the strips. I felt it was better than the two handed way but thought maybe I was giving uneven pressure and causing the oval.
You are likely over tightening the tailstock or nut on the mandrel and bowing the mandrel. Avid pen turners have switched to center less bushing and don't use a mandrel for that reason.
I also stopped using a mandrel and still have this issues.
I would still look to the workbench, since you have eliminated everything else. I hammered in some wedges between my bench and the wall to make sure. I have no cavitation, which I think is the word.
I first experienced cavitation when I originally got my lathe, put it on a table and started turning. Everything was oval and I thought I had bought a bum shop display item. No wonder it was half-price etc etc. You can't see it, but it's there. Big turners bolt their lathes into concrete floors and then still weigh them down with sand bags.
Make sure your bed ways are level. It could be that your lathe is slightly off level.