Two new stepped mandrels...

[Wade@WEBFoot]

I just made up two of each - 5/8" x 7/8" stepped and 3/4" x 7/8" stepped expanding mandrels.  They are a 7/8" Expander cut down to the stepped configuration.  I just got them on the online store.

The shank on both is 5/8" to fit in the collet chucks and is 1.5" long.  The 7/8" portion is 1" long, and the minor diameter of the mandrel (smaller diameter) is 1.5" long.  The entire mandrel is 4.00" long.

All the expanding is done on the minor diameter, the 7/8" is merely for support and centering.  It doesnt matter if the blank is all the way over the 7/8" portion or only a 1/4" on it... as long as it has about 1/4" over the 7/8" portion it will be sufficient to support and center the barrel and reduce chatter while turning.

Please, if you decide to get one of these stepped jobbies, Id really like to hear your feed back!  Whether it be by reading a review on the online store, here, or in an email.  Dont hold back, I want to hear the good or bad!  So please, let me know your experiences if you give one a whirl.

Im working on another idea that was shared with me, and am waiting for some things to get here...  once they do, I may have another way of doing the same thing, and quite possibly cheaper and more "universal".  Ill post up as I make progress on it.

Cheers all
Wade

[Ulrich's Custom Calls]

Wade just checked these out on your site and they look like a sweet setup. I am definitely going to be getting one in the near future when I get a little extra cash. I can see it really cutting down on causing off center holes while turning a goose call barrel. Right now I know if I am not careful to take light cuts on the band portion of my goose calls it can cause movement in the back of my call using only the 3/4" mandrel.  You just keep on providing use with more and more useful tools to help eliminate some headaches we all experience sometimes with call making.   

[Chris @ STW Outdoors]

Just ordered the 7/8 to 5/8 mandrel. I will give honest feedback as soon as I get it and try it. Looks very interesting.

On the boring bar idea that you mentioned. I have one of the mini metal lathes so I am not able to take very big bites out of acrylic. I understand what you are saying, but I think it would take much longer than my current method. Also, I have been pretty hesitant using the carbide on acrylic. It seems like it might get things too hot. Maybe I just need to push the limits and see what happens.

I am digging all these ideas flying around. Thanks to Wade for listening.

[Wade@WEBFoot]

Cool, appreciate it...  I know everyone does things differently, and so its good to have peoples thoughts on stuff... in case there is something that needs improved.  Cant wait to hear your experiences.

On the carbide on acrylic - its all about edge geometry, feeds and speeds.
Basically, the edge prep of the tool determines not only how it cuts the material, but also how much power it takes to cut.  And within that, there is a certain amount of heat that is expelled from the cutting process that is within the chip itself.  The more heat you can get into the chip, the less that goes into the material its being cut from.

Acrylic is a different animal compared to a lot of materials... but many of the same theories apply.
The amount of material you can take in one bite, is more related to tool rigidity and feed.  With a rigid tool, you can hog off material.   But with the mini lathe, you will battle tool rigidity.  But I would expect the problem is more related to the tool rather than the lathe...  boring bars long enough to do what we call makers want to do are right on the edge.  So one has to take advantage of the technology out there... which unfortunately means $$.   A good stiff boring bar, the right tool nose geometry, and proper feeds, speeds, and depth of cuts.  I have gotten by with a steel 1/2" boring bar, using HSS inserts, but had to be careful about feed speed and tool nose radius.  Too large of a radius promotes chatter, faster feed speed helps reduce chatter, but also reduces surface finish.  So you have to tinker around a bit to get what works for your conditions. 

Remember you can always remove heat... and its easier with a boring bar than a drill because you have a through hole, so the cooling medium has a path it can flow... whether air, coolant, oil, or what ever.

In terms of time investment, its all relative... relative to what you do... and each person is different.   What is more efficient for running 20 parts is likely very inefficient for running just one or 2000.  So just a matter of figuring out what works best for you, and where your priorities are.  Some hate polishing, some hate tunring, some hate drilling, and others hate tuning... so you just have to focus on what you dislike the most, and try and make it as easy and efficient as you can.  In machining, making good holes is one of the most expensive operations to do .  And its very evident with call making.

To me, accuracy and surface finish is key... without accuracy, you dont have repeatability, and with poor surface finish, I have to spend more time doing what I very much dislike...  sanding and polishing.  So I spend my time boring to lessen the time investment in sanding and polishing.  But thats just me :D

Cheers all
Wade

[Chris @ STW Outdoors]

That is some great info wade. Part of my problem is my lack of experience in machining. That will change with time. Thanks for the info.

[Lonehowl]

I use carbide on all my delrin and acrylic(what little I do) on my mini lathe and have never had any problems? I run a 3/8"x 6" boring bar with a carbide insert, but cant remember the actual insert type. Whatever it is it gives a smooth shiny finish inside delrin and other plastics.
Mark

[Lonehowl]

By the way Wade, I recieved the MT2 mandrel and it works great on my crow calls, thanks again!
Mark

[Wade@WEBFoot]

trtl360:
Youre nice and close... so if you want to come out sometime, I have my manual machines, just not my CNCs, so I can show you some stuff out here if that helps any.   You just have to forgive the mess...  the move has not been nice to the "organizational skills" nor the "cleaning gene" :D  My machines are larger than yours, but the theories are the same.

Heck, you could prolly bring your lil lathe with ya and we can set it up and play directly on that so you have some practical hands on with your own machine.  Just thinking outloud since youre only an hour away... if that if you drive like I used to :D


Lonehowl
Glad you got it and its working well for ya!  When I was going over what I had here to make it work... I thought that should be right up the alley you were looking for.  Glad I guessed right :D


In terms of carbide vs HSS.  If one wants to get "theoretical" and technical...  The grain structure of carbide and HSS are different.  Carbide is granules or "grains" of carbide held together, usually with a metal like cobalt.  Sort of like stabilized wood - the cobalt holds the grains together.  Think in terms of taking saw dust, mixing it with glue, and pressing it into a mold and then sanding it to shape.  HSS has a different structure, where its an alloy that rather than grains held together by a "glue", its just the "glue" itself - though tough glue.  So the "grain" structure of HSS is closer to, if not on, the molecular size.  And what this all comes to, is the sharpness of the actual cutting edge.  Carbide can never be AS SHARP on the cutting edge, as HSS because of the "size of the grains".   So in the search for the best surface finish, that edge is key.  Of course geometry also plays a large roll as well.  The places that do optical finishes on plastic (like glasses lenses) use diamond tipped cutting tools, because diamond can be sharper and is harder than HSS or Carbide.  But for the cost of the tooling, and in terms of using it on hand tools and such... just not worth the investment.  Anyway, I digress...  For the average turner in our "niche" - there is little or no discernible difference between HSS and ground carbide.  Hence, its a pretty good alternative to HSS tools.  But one does need to pay attention to the geometry of the carbide cutter.

Of course feed speed plays a big roll, as well as RPM in terms of heat... which in acrylic is a HUGE deal.  But taking your time and not cutting too hard and too fast will usually yield good results.

In terms of the boring bars...  length to diameter ratio is the biggie...  too small of a diameter coupled with long length, and you can get into chatter pretty quick.  So the largest bar you can use for the hole youre working with will give you the best results.  Couple that with the right insert geometry and things get better fast.  Go the wrong way, and things get worse even faster.

Just like call making... you cant be afraid to experiment.  Sometimes a faster feed, lighter cut, and slower RPM will eliminate chatter,  other times, you need to take a much heavier cut, keep the RPMs up and slow the feed.  And it can change on you from cut to cut.  5/8 might act one way, and 7/8 be the opposite so dont be afraid to experiment.  And if it works, go with it.  Since thats the goal.

If anyone is trying a boring bar... and the smallest bore you have is 5/8", I suggest a 1/2" boring bar.  Usually the min bore size on a 1/2" bar is around .580"...  drill er out to 1/2" or 9/16" and do the rest with the bar.  Though it will take longer to do the actual cutting... the difference in surface finish when polishing can make up for the time spent boring... and if you get er dialed in, can eliminate the need to sand altogether, and you can just polish and be on your merry way.

Cheers all!
Wade

[Chris @ STW Outdoors]

Wade,
Great info. I will take you up on your offer to visit. I did visit you a couple of years ago at your old place while i was on my way to Nebraska for some whitetail hunting. Learned alot on that visit. How far are you from the fort morgan airport? I fly out there on occasion.

[Wade@WEBFoot]

Fly?  holy crap...  yer way outta my league...  :D  Never even stepped foot inside an airplane.   

No idea, not sure where the Ft Morgan air port is.  But Im basically south of I-76 2 miles on Hwy 52, and then a mile east.  But Ft Morgan is only about 14 miles east of us.

[Chris @ STW Outdoors]

Well, as soon as I get some time we can hook up. If I do fly out there then I will have to buzz you around, as long as you're not afraid of heights.

[Wade@WEBFoot]

Um not afraid of heights...  dunno if Im afraid of planes 

[Chris @ STW Outdoors]

Just got the 5/8 x 7/8 x 5/8 stepped mandrel the other day. I chucked it up on the lathe and it did exactly what Wade designed it for. I will give the cons to the mandrel first. Actually, I should say con, as there is only one. It is a little difficult to get to the inside of the mouth piece for finishing because of the 5/8 section needing to be pretty far into the call in order to use it like how I think it should be used to stabalize the blank. This means that I would turn the call then have to change mandrels to fininsh that part. However, if you finish the inside in some other fashion, then no worrys. Now for the up side. Unlike, the 7/8 mandrel, there is no need to change mandrels when you want to flip the call. This is a good time saver. I have a small problem with the mandrel only because I really need to turn with a live center on my blank. This is because I use a shop smith and the dynamics of the lathe require me to use the tail stock to keep things running true. However, this mandrel is the first one I have used that let me get away with turnning a blank without the live center. Wasnt great, but I got away with it. For guys who like to turn blanks without a tail stock and use a 7/8 to 5/8 inside dimension, this is the mandrel you have been waiting for. It gives great stability and allows you to flip the call with out a mandrel change. I would think that you could get a lot of your inside the the mouth piece finishing done just by slipping the call farther up the mandrel. Of course that is where the 7/8 mandrel that Wade just put out comes in handy. Overall, this is a great tool that certainly has its place in the shop. I am just unsure as to how large that place truly is. Like you said earlier Wade, most guys have already achieved good work-arounds for the issues that this mandrel solves. I think that for me, the 7/8 mandrel that you came out with really made my life much easier and is probably going to be one of my major work horses, but I will keep trying this one out to see. So, there you go. The good, bad and ugly of it. At least in my opinion.

[Wade@WEBFoot]

Rock on brother!  Thanks so much!

If you get a wild hair, feel free to post that as a review on the online store.  But dont feel like you have to.... only if you want to.

I appreciate the good honest review!  And Im sure many others will too!

Wade

[Wade@WEBFoot]

Anyone else got updates on what they think of the stepped mandrels?

There are 4 out there, and trtl360 has spoken :D  Any of your other three have thoughts?
Good - bad - ugly?  Well, we can leave me out of this, so just the good and bad :D

All the best
Wade