I have been using a Sigma DG 70x300 lens on my Nikon D-60

Chuck, sorry for the late response. Last days I had to work through several hundred anonymous questions. Most irrelevant and not complete, so I could not answer most of them, but I had to read them all.
Sigma, does not have a service, where you can download a manual. But the manuals from Nikon, most of the time don't tell anything about how to use the lens.
I found a page with all specs. The link is down here.

I have to guess why you did put the question here in the first place. I think because you have a Nikon camera without a focus motor. Like a D3x00 or the D5x00 or a D40 or D60. (for the x you can add 0 1 2 or 3)
If you have one of these camera's the lens can't be used with auto focus You only can use the lens in manual focus. Most other camera's from Nikon, like D80 D90 D7000 D300 and more expensive, all do have a focus motor and can work with this lens in full automatic focus mode.

50mm F2 8 EX DG Macro

Could you be a little more specific about "does not work"? Does the lens not fit? Can you not view through the lens when it's attached? Does it not autofocus? Does it not meter the exposure properly?

Assuming the lens has a Nikon mount, then it will fit and work on the D60. Sigma makes lenses for a variety of cameras; a lens with a Canon mount, for example, will not fit onto a Nikon camera. However, the 70-210 is a rather old lens. Unless it specifies "HSM" it will not autofocus on the D60. The D60 does not have an autofocus motor, relying on the lens to have one. Nikon calls such lenses "AF-S" while Sigma designates theirs "HSM".

The Nikon D40 does not have an autofocus motor, relying on the lens having one. This Sigma lens does not have such a motor, relying on the camera having one. Nikon designates lenses with an autofocus motor AF-S, Sigma calls theirs HSM.

The Sigma 70-300mm f/4-5.6 DG will not autofocus with the D40 since the lens does not feature an internal focusing motor (HSM). The D40 does not have an AF motor in the body and hence it can autofocus only with lenses featuring an integrated motor (eg. Nikon AF-S lenses, Sigma HSM lenses, Tokina DX II series etc). Unfortunately you can use the said lens only in MF mode.

Unfortunately, you don't. The D3000 does not have an autofocus motor; it relies on the the lens having one. This particular Sigma lens, unlike its Nikon equivalent, does not have a motor.

Nikon calls their lenses with an autofocus motor AF-S. Sigma calls theirs HSM.

Hi I had a similar problem with a 50mm prime and I fixed it by locking the aperture ring on the lens in place.

If it's an AF teleconverter you will be able to use it and get proper exposure from the camera, but it will not autofocus with the D60. The D60 requires AF-S lenses and teleconverters for autofocus.

All Sigma:
50-500mm f/4-6.3 DG
50-150mm f/2.8 EX DC HSM
70-200mm f/2.8 DG MACRO
80-400mm f/4.5-5.6
100-300mm f/4 DG
120-300mm f/2.8 DG

I will try to help you, but please understand that my experience is with Nikon film cameras. Assuming that the D60 works in a manner similar to a Nikon 35 mm body and that Sigma macro lens work like Nikon macro lens, you should be able to determine the usable subject to lens distance by experimentation. First, make sure the lens is in the macro mode. To do this you must set the auto-focus mode control to the manual focus mode (see your manual). On Nikon lenses, you must first set the focus ring to infinity, then move slider switch, which has two positions marked; "normal" and "macro., to the macro position. You should now be able to rotate the focus ring to the macro range. Use the zoom ring to zoom in and out and focus with the focus ring. The the range over which the lens to subject to lens distance will yield an in focus image will be rather limited and in the range of an inch or so to 6 or 8 inches.