Shop Table top crane

[Janger]

Don't mean to be critical Gennady but I'm a little concerned with your safety. Welded right through the paint & rust? I think those welds might be sus... I do admire building from material you have and making it work. Maybe grind off all the paint, rust, welding, and re-weld. If you're in the Calgary area I can give you a boat winch with a nylon belt strap and hook. (I have a few extra) If that would help.

 

[Gennady]

Thanks Janger. I am in Ottawa,
Regarding welding - I am grinding away rust and paint to the bare metal, It might be not seen on the picture though. I am a bad welder though, no doubt. but you are right - tomorrow I will re-weld it, cleaning better

 

[Gennady]

This is how hand winch will be mounted - back of the column.

Here is the telescoping boom with pulley. And I cleaned metal before welding. Cannot get this stick weld nice and tidy

 

[LenVW]

I understand the use of a crane on the mill.

Just make sure you have a large enough (3/8-1/2” thk.) plate that will tie to the T Slots of the table.
If you have too much over-hung load you could damage the table ways and derail the table.

Most mill tables are cast iron and susceptible to stress cracks and failure under large loads.
Cover your table with plywood to reduce impacts when loading the work-holding and rotary table devices.
(A few small pieces of plywood are great shock absorbers)

 

[phaxtris]

The welds might be ugly, but they look burned in hot and i dont see anywhere with lack of fusion. From what can be seen in the picture i doubt you will have any problems with them, stick has no real issue burning through one or two layers of paint

 

[Martin w]

You did a nice job, looks great!
I have a cable and turnbuckle on my wall jib crane to help take the strain of heavier loads.

Martin

 

[Gennady]

If you have too much over-hung load you could damage the table ways and derail the table

Many people here and in other forums are warning about that and I am really worried, on other hand many people did the same type of crane and mounted it same way - on the mill table. Mr Pete (Tubalcane) - I took his idea - mentioned that most obvious reason for damaging ways is misused T-nut that is becoming a jack and prying out slot. In any case I will made a plate wide enough to ensure greater support.

 

[jorogi]

Best idea I saw was to make an off balance lifting attachment with an extension bar that is on the light side and thus points up slightly rather than having the accessory hanging level. You use the bar to keep the accessory level as you lower it, an inch or so up you stop, and then ease it down by raising the bar.

 

[Susquatch]

Mr Pete (Tubalcane) - I took his idea - mentioned that most obvious reason for damaging ways is misused T-nut that is becoming a jack and prying out slot.

That is just one way of damaging a T-slot. The other way is tension overload. Most cast iron is strong in compression but has low tensile strength compared to steel. By its very nature, you will be creating a tensile load on your T-Slots with a base such as you have shown. Lots of people do it and get away with it. But you don't want to be the one who doesn't.

If you have decided to do this anyway, I'd increase the size of your T-nuts and I'd increase the number of them. Especially on the tension side of your base. Your drawing shows 4 bolts. Why not 8? Doubling the number of bolts cuts the load for each of them roughly in half. I say roughly, because the load distribution is not perfect - the ones in the center will see more load than those on the outside because the plate will Flex.

You can also make longer t-nuts to increase the bearing area. You will find that there is a limit to their length imposed by the access port. But you can remove or tilt the crank base to slip longer ones in.

 

[Gennady]

But you don't want to be the one who doesn't.

After quite a few reasonable warnings I gave it a second thought and decided NOT to mount it on the mill table. I would rather do a wooden cart-pedestal with front legs extending forward to ensure balance - similar to engine hoist. Bottom surface can be used as a storage for vise, dividing head, rotary table and it will add stability to the cart.
Something like that -

Crane itself will not be swivelling. The cons of this solution is yet another structure taking place in the shop.

 

[Susquatch]

The cons of this solution is yet another structure taking place in the shop.

Nah, I call it reconfigurable, moveable storage.

I keep my 10" rotary table and 160lb optical indexer on the top of a tall rolling tool cabinet. I pull the cabinet over to my mill, lower the table slightly below the cabinet, and slide the heavy stuff over onto the mill. When it's time to put them back, I raise the mill table slightly above the cabinet and slide them off. It's very easy to do, but I am a big guy.

I can easily move my 60 pound universal dividing head, but I might put it on the tool cabinet too. The rolling cabinet is designed to take a 600 pound top cabinet so I'm not worried about overloading it.

 

[phaxtris]

How far away from the mill table are you trying to grab things from ? You could just mount a pulley to the roof joists run your cable down to a convenient location for the winch. Winch the part up, drift it over with one hand and winch down with the other.

The more cable you have from the pulley to piece the further and easier you will be able to drift your part over.

That would be the simplest solution imo