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Maximat 7 Mill Drawbar Question

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Brokk

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My wife bought us a Maximat 7, which has a lathe and a mill.

I grew up around an Atlas mill, and although my dad rarely let me within 5' of it, at least I saw how it worked and operated and I grew to have a working knowledge of the bits and pieces. I'm no expert, but I manage to get work done without breaking anything. (he has passed away and the Atlas passed to me)

When it comes to mills, I have no clue. My wife thought she knew about them from using them in school, but she is used to a big Bridgeport setup and also has no clue how these hobby versions work.

The Maximat 7 has a has an MT2 spindle, and I haven't seen anything in the documentation that mentions a drawbar. Yet when I ask around on other sites, I have heard that you are crazy not to use one.

http://www.lathes.co.uk/emco/page4.html

I have a set of collets that came with the machine, but the collet chuck is not an MT2, so I'll need to buy one to work with the the mill. What I'm wrestling with is figuring out what I need for a drawbar, which would then need to match up with whatever collet chuck I purchase.

Does anyone have one of these? I believe the same mill was used with the V10 as well.

Any idea what I would need to measure to get on the right path for figuring out what I need for a drawbar?

Brokk...
 

MozamPete

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#2
I have a MT2 to ER25 chuck and a MT2 to ER32 chuck I use on my Myford lathe. Both just have a M10 internal thread in the end for a draw bar so I just used a length of threaded rod. After using it once I marked the required length, cut it and welded the nut in place. Also put a bit of heashrink over the unused thread just to stop it scratching things up. The headstock and the tailstock use different lengths so I made two.

image.jpg
 

Brokk

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I have a MT2 to ER25 chuck and a MT2 to ER32 chuck I use on my Myford lathe. Both just have a M10 internal thread in the end for a draw bar so I just used a length of threaded rod. After using it once I marked the required length, cut it and welded the nut in place. Also put a bit of heashrink over the unused thread just to stop it scratching things up. The headstock and the tailstock use different lengths so I made two.

View attachment 96310
Thank you!

An excellent answer. Now I have a plan to execute.
 

Brokk

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#4
It turns out the collet set that came with the mill are actually AF collets. I looked for a collet chuck for them, but they are all close to $300, and they don't come in a morse taper, so I would need to also get some sort of adapter to get them to work with this mill. Just not worth it.

Now I'm pricing out ER sets and chucks. Is there a preference in sizing? I am leaning towards something larger, like an ER25, although ER16 is the most prevalent. I was just figuring something larger would give me a better range of larger tools I could use. I can't see me using anything really tiny.
 

MozamPete

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You could also go straight for MT2 collets. They don't seem very popular anymore, not sure why, but you can still get them. Something like http://www.ebay.com/itm/151570587587?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT


Logically you would think that they would be more accurate as there is one less interface to introduce error/runout than having an ER collet and then a Morse Taper.


I originally brought an ER20 set for milling on the lathe (not ER25 as I said before) but found the 13mm max size a bit limiting, so I upgraded to an ER32 set (20mm max from memory). I'm planning to change my mill to an ER32 chuck (at present it has when appears to be a non standard proprietary collet which is a real pain to remove from the chuck).
 

Brokk

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I have a MT2 to ER25 chuck and a MT2 to ER32 chuck I use on my Myford lathe. Both just have a M10 internal thread in the end for a draw bar so I just used a length of threaded rod. After using it once I marked the required length, cut it and welded the nut in place. Also put a bit of heashrink over the unused thread just to stop it scratching things up. The headstock and the tailstock use different lengths so I made two.
So, I ordered a few things. MT2 collet set, ER25 chuck and collets. Everything threaded for an M10 drawbar.

The MT2 collets are the first to show up. I go to the workshop, the collet fits perfectly. I look around for a length of M10 threaded stock, feed it into the top to find the length and... Yup. Won't fit.

The ID of the tube at the top of the mill is too small for the diameter of M10. (sigh)

Yes, I likely should have checked this beforehand, but the only two options when ordering things came in M10, or 3/8. Both of which are too large to fit. So I'm not sure it would do me much good.

So now it gets a little trickier, as M10 fits in the MT2 section, but then it changes to this other ID until the top. So I'll need to find out how much M10 space that is, as well as how much thread I need to draw up the collet (or collet chuck), then turn down the rest of the length to that ID and rig up *something* at the top, so I can tighten it the drawbar with some amount of levered force, as well as making it either removable, or lockable so that I can take the draw bar out when I need to put in something that doesn't use a drawbar (though I'm not sure how often that would be).
 

MozamPete

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#7
M10 to M8 insert loctited in each collet and a M8 drawbar?
 

Brokk

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M10 to M8 insert loctited in each collet and a M8 drawbar?
I'll have to measure the depth of the MT2 and compare it to the collet to figure out how much wiggle room I would have for the M8 female, but that could work...

Thanks for the idea.
 

Brokk

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The M10 to M8 insert path has turned out to be hard to find, and expensive when I did find it. With shipping, it was going to run me about $20 for one, and I would need one for each collet, making the price for just the inserts more expensive than the set of collets. I'm currently trying to make my own, by buying M8 nut couplers and welding them to M10 threaded stock on one end. Then turning down the coupler on the lathe to make it a small enough profile to fit into the top of the MT2 space. Now I have some long hex M8 bolts on order to use as the draw bar. Then I can try it out to see if it works. Rather than $20 for each one, it this will cost me more in time and effort, but only cost a about $3 for each one.
 

markba633csi

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#10
I would have done it differently. Make one drawbar with m8 (or maybe 1/4-20 or 1/4-28) at the top and m10 for the lower section. Of course you need a lathe for that. And a threading die(or dies). More elegant tho. Anyways, thanks for the posting cause now I've learned something new about the Emco mill powerhead. I assume the FB-2 mill is the same.
Mark S.
Mt. View, Ca
 
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