How to "shorten" an Alliant Mill

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sb9a

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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?
 
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.
 
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?
 
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.
 
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.
 
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.
 
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.
 
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.
Click to expand...

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!
 
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?
 
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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