# How to "shorten" an Alliant Mill



## sb9a (Jan 16, 2014)

OK, here's a potentially stupid question.

I have a basement workshop with a ceiling height of 81".  I have a nice Alliant vertical mill in storage which is 81" tall.  My question is has anyone been down the road of trying to reduce the height of a Bridgeport type mill to install it in a height constricted area?

Some irrational thoughts I had were:

1.  Cut down the base of the column with a cutting wheel and grinder.  Don't know how much height could be taken off, maybe 1 - 1.5"?
2.  Cut a hole out of my basement floor and pour a recessed footing.
3.  Install a shorter motor on the mill.


Any ideas?


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## toag (Jan 16, 2014)

is that 81" between thee rafters?  If not there is about 10-12" there depending.

I think trying to cut the casting is a huge undertaking and would require a very large machine.  you would want to be precise or your mill would suffer rigidity and accuracy.  so alot of effort for 1" room. 
going down might be easier... but that is still alot of effort. and you would need something to remove the chips and oil that will accumulate.  I think a pancake motor is easiest if you are dead set to have it in the basement.
if you are kind to the drawbar, and can get the head between 2 rafters, it should be ok.  might want a piece of foam between the head and the ceiling/floor to cut down noise.


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## sb9a (Jan 16, 2014)

Yes, the 81" is to the bottom of the joists.  I could potentially align the motor into the middle of the joist bay to get a bit of clearance.  I was thinking that since I have to essentially completely disassemble the mill to get it into the basement, I could flip the column over and trim a little off the base.  It should be pretty easy to scribe a parallel line around the base.  I wonder if something like a plasma cutter could make that a not-too-horrendous job?  Will a plasma cutter do well on cast Iron?


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## The_Crusher (Jan 17, 2014)

You would have to have a pretty strong plasma cutter to do it in one shot. Boring mill would be the best way to do it. Then you could still cut the feet and recessed areas on it and it would set level and not tip all over.


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## pineyfolks (Jan 17, 2014)

I'd cut the concrete and pour a new pad for it to set on. If you ever want to change machines you're set. Cutting the base on your machine would be a tough job to do at home and probably reduce the resale value of your machine.


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## Senna (Jan 17, 2014)

Not to be overly critical but the last thing I'd consider would be cutting the base down. The manufacturer made the base the thickness it is for a reason and reducing this thickness could cause problems with breakage not to mention the difficulty in cutting the base or making it perfectly flat and level.

A pancake motor would achieve the results you desire while not compromising the strength of the mill itself. You could use the original motor for any number of other uses throughout your shop or you could sell it to help defray the cost of the pancake motor.

Show us some pictures of this machine please.


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## sb9a (Jan 18, 2014)

Thanks, for the feedback.  I'll post some pictures of it at some point, but it's currently in storage in an aircraft hanger (for the last 16 years) covered with cosmolene.  Next month, I plan to start disassembling it and hauling it home piece-by-piece.I am now inclined to cut into my slab and pour a footing for the machine.  I'm not sure how thick the basement floor is and I would like to have a stable foundation under the machine to avoid floor cracking and structural damage to the house.  Would a Bridgeport "pancake" motor fit an Alliant mill?  Are there aftermarket "Pancake" motors available and who are sources?Until I get the Alliant set up, I'm relying on my well tooled Atlas MFC Horizontal for milling capability.The concept of a basement shop works out well in "Taxachusetts" where I unfortunately live.  The basement never gets below 49F. in the winter and I avoid the R.E. taxes of a permanent outbuilding with a slab.  I have a couple of "temporary"  sheds on the property where I do dirty operations such as: table saw, bead blasting and flammable stuff like welding.


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## Marco Bernardini (Jan 18, 2014)

sb9a said:


> I'm not sure how thick the basement floor is and I would like to have a stable foundation under the machine to avoid floor cracking and structural damage to the house.



Before to dig make 5 sampling holes (corners and center) with a large - and long - stone bit, to verify the thickness of the floor and to see what's below.
You can make a clean cut in the floor with an angle grinder and a diamond disc (a lot of dust, have something to extract it from the basement!) but this saves a lot of dangerous vibrations to the house.
Before to pour concrete on the soil don't forget an insulation layer, to prevent damp from below.
A good idea would also be a hole at least 4" larger than the mill, with a sort of 2" reinforced concrete "bezel" all around, using rebars more or less Ø 12mm. The best solution would be to have the rebars surrounding all the hole.

Have fun!


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## sb9a (Jan 19, 2014)

Thanks, that is good advice.  I plan to make a pretty substantial footing for the mill.

What are some opinions on the minimum floor thickness for supporting a full size mill?  I know there are some hollow sounding spots on my floor, so I would not be surprised if it was as thin as 2" in some spots.  I guess test borings are the way to find out.  Is floor thickness a concern with other basement shop guys, or am I over-thinking this thing?


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## pineyfolks (Jan 19, 2014)

After you remove the section of floor, I would make it 4 to 5 in. deep and dig a post hole in the center. Or one on each corner if you like digging. :miner:


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## toag (Jan 19, 2014)

I gave this a smidge of thought and here would be my suggestions from a guy that spent one summer forming concrete.  ideal would be tieing into the existing foundation with some no4 rebar. I would also make the new pad about a foot bigger on each side of the mill, maybe more in the front if you are tallish.
i would make the pad an easy 6" and use mesh.  I would make the sides 8" (making a mini footer). and i would drill holes into the sides of the existing slab with a 1/2" bit.  slide the bent no4 into those holes then tie the no4 to the mesh.  throw in a few bars accross for ****s and giggles, and spend the next day carrying buckets of concrete in.
the idea is overkill is way easier than doing it twice, or worse having your mill list after 3 winters.
dont forget some visqueen, pick up some heavy duty in the painting section of home despot or Lower than Lowes.


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## Al 1 (Jan 19, 2014)

*Re: How to &quot;shorten&quot; an Alliant Mill*

SBA9,

        If you only need a small bit for height, and you have a standard lumber joist: like a 2" x 10",  Why not beaf up your joists to lets say for an example a double 2" x 8".

     There are joist span tables that you can use.  If you have questions , contact me.

                  Al.

- - - Updated - - -

SB9    So what you  would be doing is removing a section of the bottom of the joist and doubling the width.
      Al.


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## sb9a (Jan 19, 2014)

Unfortunately the existing joists are 2 x 8.  Its a 1962 vintage house.


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## John Hasler (Jan 19, 2014)

sb9a said:


> Unfortunately the existing joists are 2 x 8.  It's a 1962 vintage house.



Then scab on a 2 x 6 on each side.  Another option might be to use steel.


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## jererp (Jan 19, 2014)

Lazy Boy headquarters has a section of the original shop preserved as part of their museum.  More than one of their machines in that original shop was positioned between the rafters for clearance.  I would opt for that first, then putting it in a pit as a second option.  Just be careful of creating a trip hazard with the pit option.  You'd hate to be concentrating on machining a part, move slightly to get a better view of what is going on, and stumble into a rotating spindle.


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## Ed T (Jan 20, 2014)

+1 on trying it between the joists first just to see if it's impossible to live with. If you decide to sink the floor how do you propose to get the machine into and out of the pit. Is this a step pulley machine? If so, you might be able to come up with an arrangement to off set the motor and mount it upside down off the back or side of the machine. Make a jackshaft to mount the motor pulley where it originally was mounted and drive it with a 1-1 pulley arrangement from the offset motor. This presumes that the motor is the tallest part of the machine.


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## sb9a (Jan 20, 2014)

I'm starting to warm up to the idea of centering the motor between the joists.  It is a vari-speed drive configuration, so I'm stuck with the motor "up".  The height of the mill should be about equal, or 1/4" or so lower than the joists depending on what the true hieght is after I level it up.  In deciding whether, or not cut and pour a footing, what is the minimum existing floor thickness I could accept as safe (determined by test bores)?


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## Marco Bernardini (Jan 21, 2014)

sb9a said:


> what is the minimum existing floor thickness I could accept as safe (determined by test bores)?



It depends by the quality of the floor.
If the house was made in the '60 I assume the quality was not very high (at least here in Italy: in those years we had a "building bubble" with a lot of quick-made homes).
To be on the safe side my guess is 8 inches, assuming the weight of the mill is evenly distributed, but this depends by the gravel/cement ratio.
To test the hardness of the concrete there is an instrument called _sclerometer_, but I strongly suggest you to show the floor to a structural engineer, possibly one with a direct experience of 1960 building methods.
Don't forget the vibration damping, too: old building don't love too many vibrations.


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## Marco Bernardini (Jan 21, 2014)

sb9a,
not to scare you about the robustness of a floor, but take a look at the images 14, 15 and 16 of this slideshow reported by the Italian newspaper "Il Corriere della Sera":

http://www.corriere.it/foto-gallery/cronache/14_gennaio_17/treno-deragliato-ad-andora-fd81229c-7f94-11e3-aa77-33cce3d824e3.shtml#14

As you can see, the parking lot now half-way down the hill is "robust", like the wall below it, because they didn't break after the landslide, even if now it's not economically reasonable to recover them.
Many years ago I went on that same parking lot to make some land surveying, and it was totally "vibration free".
But sometimes just "robust" is not enough, when considered out of the surrounding context!


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## sb9a (Jan 21, 2014)

Hello Marco,

Not only does it scare me about cement structural integrity, I'm also a bit worried about my trip home tonight on the commuter rail!!


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## Walt (Jan 21, 2014)

John Hasler said:


> Then scab on a 2 x 6 on each side.  Another option might be to use steel.



^^This. 

If you even need more room than between the joists. Perfectly acceptable practice if done well. Consider hiring a pro if you are concerned. (I believe this is referred to as "sistering" the joists.)

http://www.familyhandyman.com/floor...al-repairs-by-sistering-floor-joists/view-all

Walt


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