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Goliath CNC knee mill

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Goliath CNC knee mill

Postby MFleet » Wed Jan 17, 2018 1:42 am

This is what a 6500# + CNC knee mill looks like. I'm less than pleased to announce a series of miscalculations on this.

My original thought was that a CNC knee mill, on average, should not go over 4k#. I still stand by that thought as being logical. After more picture analysis....this is no average casting. More like 5k# plus another 1k# for the cnc bits. That killed the idea of using the available 7K# trailer to pick it up. That would have been a rough estimate of $500 personal transport cost.

I made the deal on it and hired a rigger that could do 6k#, no problem. Add an 8k# local forklift rental onto that. We made it to my shop and he went back to pick up a 6k# skid steer. The skid steer didn't want anything to do with it. I removed the ram and milling head assembly to lose what I estimate to be 750-1000#. The skid steer reluctantly moved it into where you see it. He is claiming that it is still over 6k# for the lower assembly and that may be true.

The rigger was slightly irritated after I carved out the most cash that I could muster for this move. I offered my shop time to cool down the situation and his demeanor changed quite a bit. I put the Hypertherm to work. There is a gross amount of plasma arc gouging on his trailer. There is several more hours of thinking, hammering, cleaning, welding, wire soldering, whatever. I don't have the immediate know-how to do double pivot point equipment ramps or we would have done those as well. Anyhow, I think both of us can agree that I'm now in the positive side of the deal.

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Re: Goliath CNC knee mill

Postby aland » Wed Jan 17, 2018 2:35 am

I'd like to see a skid steer that can lift 6,000 lbs. 2500 is more like it for a skid steer.
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Re: Goliath CNC knee mill

Postby MFleet » Wed Jan 17, 2018 4:32 am

aland wrote:I'd like to see a skid steer that can lift 6,000 lbs. 2500 is more like it for a skid steer.

You may be right on that. I remember it having tracks which would make it a track loader; not a skid steer as the guy was calling it. I think it was a Bobcat. I will get a picture if I ever make it back over to his place.
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Re: Goliath CNC knee mill

Postby Farmwelding » Wed Jan 17, 2018 6:27 am

aland wrote:I'd like to see a skid steer that can lift 6,000 lbs. 2500 is more like it for a skid steer.

If I remember right, skid steer lift ratings typically are for at full lift height with movement. If you leave that sucker no more than a foot off the ground you can do a lot of work. Pallet forks may start to bend but that's a separate issue. I may have also heard the woeful rating thing wrong as well.
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Re: Goliath CNC knee mill

Postby MinnesotaDave » Wed Jan 17, 2018 8:05 am

aland wrote:I'd like to see a skid steer that can lift 6,000 lbs. 2500 is more like it for a skid steer.


Bobcat s850
3950 lift and carry
7900 tip

Screenshot_2018-01-17-06-03-50.png
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Re: Goliath CNC knee mill

Postby Farmwelding » Wed Jan 17, 2018 8:55 am

MinnesotaDave wrote:
aland wrote:I'd like to see a skid steer that can lift 6,000 lbs. 2500 is more like it for a skid steer.


Bobcat s850
3950 lift and carry
7900 tip

Screenshot_2018-01-17-06-03-50.png

I wish our bobcat could 12.3 mph... And lift that much. Ours is an S205 so rated at 2050 lbs but I've lifted mini bulks with herbicide that are around 3000 lbs. the main thing is keeping the load tight to the loader as well. Ours wouldn't pick up our man lift because of the length of the man lift. Too much leverage in the front end. If it has fork holes on the side in sure I could have but too much weight 10 feet away from the loader it self wouldn't let it lift.
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Re: Goliath CNC knee mill

Postby aland » Wed Jan 17, 2018 2:59 pm

MinnesotaDave wrote:Bobcat s850
3950 lift and carry
7900 tip


Pretty familiar with the most skid steers, and although the s850 spec says that, I'd love to see it in action.

For reference, I own a Catapillar R-80 Rough Terriain forklift, it will lift 8,000 lbs, but it does that only on the 1st stage, so it lifts 8,000 lbs. to 10', not the full 30' with all 3 stages extended. Full height is more like 2,000 lbs to max height, and that is not tilted in any way.

Skid steers don't have multiple stages and are limited at the full extension of the lift, that would be no issues for a machine if you only need to live it a few inches, but to unload it you need to get higher as you need to get to the trailer bed.

Even still, let's just say the s850 will lift 4,000 lbs. to full dead lift. That is still quite a ways from a 6,500 lb. CNC mill.

Honestly, I wish a skid steer would lift more as I would trade my forklift for one, but I often lift logs with it that weigh 4,000 - 6,000 lbs. I don't think a skid steer can handle that and a good friend convinced me to give up on the idea. The other thing is the entire weigh of a skid steer, you need ballast when lifting. My forklift weighs 16,000 lbs. If you are not careful you can easily pull the entire lift over with a 3,000 lb. load if you tilt the mast too far forward. I have never lifted a machine that heavy, but my lathe weighs 4,000 lbs, and I've lifted it easily.

EDIT: Farmwelding you've got it right. Keep it low, keep it close, keep the weight down if you can. :)

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Re: Goliath CNC knee mill

Postby MFleet » Wed Jan 17, 2018 8:45 pm

I've done some checking and found that we used a Bobcat T870 to unload it. There was planning and a skilled operator to pull it off. That doesn't make it safe or right in any way. Don't do what we did. We used a Skytrak 8K# to load it and that handled it, no problem.

The moving costs ate the budget to convert it from 3ph to 1ph power. Another reason I'm still a bit cranky about the whole ordeal. I've also sold my manual machines. It is still a good deal and very much needed to move forward.


This is the early planning stages to get this running:

Aquire a name brand VFD to to convert the 5hp spindle to single phase.

Address shaft-pulley tolerance in the upper milling head. Replace 3 worn bearings. Remove worn spindle air brake components. The VFD will handle spindle braking. Add spindle encoder if necessary for rigid tapping.
I don't have the parts manual for the milling head. It is a Dah Lih brand and I would love to have one, but I can get by without it.

The CNC controller is a 1992 vintage Anilam 1400(M?). It is all single phase so no problems there. The electrolytic capacitors and old, dry heat sink compund will be freshened up. A LinuxCNC/Mesa controller may be in the future. I'm also liking the controller and conversational software package from Centroid. The prices can get way up there with Centroid however.

The power knee and coolant pump are 3 phase. I'm still undecided on what to do them until I can get the motor specs.
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Re: Goliath CNC knee mill

Postby aland » Thu Jan 18, 2018 12:49 am

MFleet wrote:I've done some checking and found that we used a Bobcat T870 to unload it. There was planning and a skilled operator to pull it off. That doesn't make it safe or right in any way. Don't do what we did.


I agree, the operating weight on that steer is 5000 lbs., however the tipping load is 10000 lbs. so that seems within the spec.

Seems you got it moved and that is what counts. Thankfully nobody was hurt and the machine was not dropped in the process. I guess you can't argue with success, but it doesn't seem like a very smart move for a "skilled" operator, IMO. But my opinion means little. As I said, you got it moved and nobody was harmed.

http://www.ritchiespecs.com/specificati ... lid=108873

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Re: Goliath CNC knee mill

Postby Homemade » Sat Jan 27, 2018 5:07 pm

Would a 5 hp phase converter be cheaper then a single phase spindle motor and solve the 3phase coolant pump issue.
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