Mandrel Problems?

[knottyharry]

I'm having a problem with my mandrel I think.
The lathe I have is a Grizzly lathe 35 1/2 inches.
It has a #2mt mandrel. It is an adjustable one, where you can loosen the collet and slide it in and out as needed. I got it from PSI.
But for some reason, it is not dead on when you line it up with the tailstock. And I am constantly having to mess with it. And i'm getting tired of it. I kind of think it is something in the collet. When you go to tighten it.
So here is my question to all of you.
Where would you go to buy a new mandrel. Who has the better mandrel out there.
I think this is where I should go from here???????
Please give me your thoughts on this if you will.
Thanks
Harry

 

[Daniel]

Harry,
You can check the mandrel for straightness in a couple of ways. one is to keep it mounted in the lathe and then use some guide mounted to the tool rest like a pointer or better yet a dial indicator. anything that shows the exact point the mandrel is from the tool rest at the headstock/ then move the tool rest along the lenght of the mandrel this distance should stay the same. second you can take the mandrel and roll it on a flat surface. if it rolls smoothly with out bobbing up and down. the mandrel is fine. you may need to check your head and tail stock alignment. that is a bit more difficult. I have seen a fairly good description of it before and will try and find it again. my lathe is notoriously bad about this as the bed is a pipe so setting it up is very particular. I have heard comments from others that they are not real happy with the type of mandrel you have I simply use the plain old mandrel from P.S.I. with the taper on it.actually added a chuck to my lathe recently so I don't even need the taper anymore.

 

[Rifleman1776]

You need to check whether your lathe is in alingment. That is very easy to do. Just put your spur into the headstock and your regular point in the tailstock then slide the tailstock all the way to the head. If the two points touch, you are alright. You can do this along the whole length of the bed as your lathe allows the headstock to move also. If they don't line up, and you are still in warranty, call Grizzly. If they do line up, call whoever you bought your mandrel from.

 

[wayneis]

Harry a lot of people have complained about the adjustable mandrels from both PSI and Woodcraft. What I've gleened so far is that they are not worth the money and you should stick to one of the other ways, MT #1 or 2 or the Beall Collet Chuck and now I notice in the CSUSA catalog that Oneway has a collet chuck out. If you are going to go with one of the Morse Tapers then I would spend a couple more dollars and get the good one from Berea. I use the Beall Collet Chuck and really like it but it is rather expensive if all you do is turn a few pens. The short of it is to try to get your money back and get a new mandrel. Hope that I helped a little anyway.

Wayne

Wayne

 

[dougle40]

I have one of these types of mandrels and I found that the key is to make sure that the headstock end of the mandrel shaft is still inside the hole in the MT , even if it's only by 1/4" , this will stabilize it and prevent the wobble that you're experiencing . Another thing that I learned is to tighten the collet while the tailstock end is held in place by the live centre (providing that your live centre is square to the headstock) , this will give you a much more true turning shaft .

 

[rtjw]

PSI has some good mandrels. I would check with pens of color also. She carries PSI and is pretty good on prices.

 

[jdavis]

First I would check alignment of lathe components. We do not use adjustible mandrels. Our mandrels come from PSI.I have to watch and make sure the students are not tightening the brass nut too tight as I have had mandrels tobend causing miss alignment.

 

[dougle40]

I have to watch and make sure the students are not tightening the brass nut too tight

I actually had to take the brass nut off my mandrel and replace it with a regular nut . I found that it just kept getting tighter the longer I turned which did cause the bow effect .

 

[driften]

I have also had problems with the woodcraft adjustable mandrel. Its fine when setup short for turning a 2-3" part. It just does not like doing a full pen at once with out too much run out. The mandrel shaft is fine. So I have gone to the non-adjustable mandrel for nonmal stuff and the adjustable one for things like the Atlas or small things.

 

[knottyharry]

Thanks for your comments. It gives me a little more insight to the problem.
Harry