Mandrel clarifications?

[Raymond]

Aren't all 7mm ("A") mandrels created equal? I read somewhere on this site of people reporting that some bushings, when used on the PSI mandrels, are "loose" and that PSI bushings don't fit onto other 7mm mandrels without sanding the mandrel down to fit the bushings. Is this a common problem? Does it apply to all adjustable Maxi Mandrels, only those sold by PSI, or might they have been referring to PSI's non-Maxi Mandrels?

I want to turn a couple dozen pens this first time out but may need to buy kits from two different suppliers. I'd like to minimize my investment in tools until I see where this hobby takes me.

What mandrels do you folks who use mandrels use?

Are there bushings that fit onto an "A" mandrel to bring its OD out to the size of a "B" mandrel? I'm thinking that that should allow me to use someone's "A" mandrel with all kits, whether the kit is made for an "A" mandrel or a "B" mandrel. What is the OD of a "B" mandrel?

Thanks.

Ray

 

[Skye]

Without directly answering your question (because I don't know the answer) I'll tell you that every manufacturer has slightly different tolerances. There's good cross-company matches and there's bad ones. Years ago there was the beginning of a 'call to arms' with the penturners to force standardization, but there's other things involved and it never really took off I don't think.

 

[Wildman]

Sanding the bushings to fit might make more sense than sanding a mandrel. If bushings are too loose on your mandrel could be more of a problem.

No, not all "A" mandrels are the same size. Not sure if you do a "Search here", for mandrel thickness," will find that information or not. Think order of thickness goes, Berea Hardwood, Craft Supplies, then PSI.

I have turned both Berea & Craft Supply kits on a PSI mandrel. Ordered some cigar kits labeled Berea Hardwoods with bushings from WoodturningZ. Ordered Click pens & bushings from Craft Supplies. Had no problems with PSI mandrel or bushings from those places.

I know for a fact neither Craft Supplies nor PSI Bushings will fit on my Berea A or B mandrel without sanding.

It's important to know if your supplier is a reseller of either Berea or PSI kits & bushings. Don't think Craft Supplies has any resellers of their pen kits & bushings.

 

[Rcd567]

Trying not to hyjack this thread...but whats the difference between say a No. 2 Morse Taper Mandrel Set and a No. 1 Morse Taper Mandrel Set? Do I need both?

Holy dog slobber batman, some of this stuff is confusing!

 

[NewLondon88]

Trying not to hyjack this thread...but whats the difference between say a No. 2 Morse Taper Mandrel Set and a No. 1 Morse Taper Mandrel Set? Do I need both?

No, you need one or the other. One will fit your lathe, the other one won't.

 

[Raymond]

Holy dog slobber batman, some of this stuff is confusing!

I hear ya. I'll just buy my mandrel from Craft Supplies when I buy the kits. But I know I need a MT1 mandrel as opposed to an MT2. It depends on the headstock of your lathe. If it's a Morse Taper 1, you need a Morse Taper 1 mandrel (and anything else you ever jam in there). If you have a Morse Taper 2 headstock, well, you get the idea. Then again, you may not need either if you use a screw-on mandrel, but then you gotta get the right size threads.

Do you need both? No. But what you might need are several MT1 (or MT2) mandrels if you get kits from different suppliers.

The problem of what fits into what goes beyond the mandrel, though. How can you drill a 7mm hole, insert a 7mm (OD) tube, then still fit a "7mm" pen mill into the hole??? Obviously, some of the tools sizes are stated in nominal sizes, which makes it all the more difficult to tell what really fits where.

Here's what I've found about mandrel sizes:

PSI claims all of their mandrels are 0.243"

Berea sells A and B mandrels for their A and B bushings.

Arizona Silhouette sells the Berea mandrels and says the A is 0.245-0.247" or at least a couple thousanths of an inch larger than the PSI mandrel. Depending on tolerances, that could explain why smaller PSI bushings don't fit on a larger Berea mandrel and why Berea bushings are loose on a PSI mandrel.

Woodcraft sells what looks kinda like a PSI adjustable mandrel, but they sell Berea kits which bushings, I have to asume, fit their mandrel.

Rockler sells a similar adjustable mandrel which says it's for 7mm bushings only. Does that mean bushings for kits that use a 7mm drill bit only? They sell kits that appear to be the same as sold by Craft Supplies. If you check some of the details, they (Rockler) list the same adjustable mandrel for turning pens that use a larger than 7mm drill bit. I'm confused.

Craft Supplies sells an adjustable mandrel that also looks like the PSI deal. They say it "fits" all of their bushings which good enough for me. I don't know if it will take PSI bushings or how close the "fit" actually is. This is the way I'm going and hoping for the best.

 

[randyrls]

Trying not to hyjack this thread...but whats the difference between say a No. 2 Morse Taper Mandrel Set and a No. 1 Morse Taper Mandrel Set? Do I need both?

Holy dog slobber batman, some of this stuff is confusing!

No; You do not need both. Look at the spec sheet for your lathe and it will normally tell you the MT# you need. There is one for the headstock, and one for the tail stock. They do not have to be the same.

MT tapers run from the smallest MT0 (zero) to around MT6 or 7 for extra jumbo. Most wood lathes are MT1, MT2, or MT3.

 

[randyrls]

Aren't all 7mm ("A") mandrels created equal? I read somewhere on this site of people reporting that some bushings, when used on the PSI mandrels, are "loose" and that PSI bushings don't fit onto other 7mm mandrels without sanding the mandrel down to fit the bushings.

Thanks.

Ray

Ray; The PSI mandrels and bushings tend to be smaller than the Berea mandrels and bushings. I use Berea mandrels, so occasionally I have to sand or ream out the PSI bushings. Not a big deal, wrap a piece of sandpaper around a 3/16" dowel and work your way evenly around the bushing until it is a slip fit.

There isn't a difference in size, but I think there is a difference in the tolerance spec. PSI may use .247 -.001, +.000 and Berea may use .247 -.000, +.001

 

[Chris Bar]

Measured my PSI mandrel at five locations, which all read .244 and several reading each on the bushings which read .247 to .248, mostly .247.
Also it seems the steel in the PSI mandrel is soft but left the hardness tester at work when I retired (they are so happy...it was theirs:biggrin. Is the steel in the CS any harder and less susceptable to bending? Just received a very large order from them but did not think about replacing just the shaft :frown:. Have been having mandrel issues with the slop of the bushing on the shaft.
Just measured the CS Jr Gent 2 and Americana twist bushings too. Same as above.... .247-.248. I need a larger shaft threaded one end.
Hope this info helps.

Chris