I recently got this t-bar anvil combo vise. I do not have a post vise.  Construction of how the jaws work seems similar to a post vise; can this be used as a post vise without undo risk of damage to the vise? 

 

No. These aren't strong enough to do more than VERY light hammer work like straightening 16d nails. Note how much damage the "anvil" face has now, from what I can see in the pic none was done by serious hammering. 

I'm not familiar with a T-bar vise as a type. 

Frosty The Lucky.

I would not use that like a post vise myself. Look at how much horizontal run in the jaws. When doing some serious pounding on it the energy will be directed on a thin piece where a post vice being more vertical the energy is directed into the body of the vice through the leg into the ground.  

Useful though? I would say yes just not for beating metal on, but there are many more uses for a vice than wolloping hot steel. I wouldnt get rid of it myself. 

Thanks for the replies. I will not use it to beat on; but I still think it is a cool looking vise.

To add to what has been said, the threads look to be more like a machinist's bench vise than a post vise.  That is, it takes more turns of the handle to move the jaws a given distance.  One of the advantages of a post vise is how fast you can close and open the jaws when you are using it to grab hot metal.  My large (6") post vise takes about 1.5 turns to move 1", my large machinist's vise, about 6 turns/inch, and my small machinist's vise about 8 turns/inch.

Another disadvantage of anvil/vise combinations is that if you mount them high enough for a vise they are too high to comfortably use the anvil and vice versa (vise versa?).

Many bnch vises have an anvil shape over the screw box but I have never used it except for very light tapping when I didn't want to walk over to the anvil.

"By hammer and hand all arts do stand."

I see broken vises on a regular basis at the scrapyard. Most vises that are NOT postvises are made from cast iron and will not take heavy hammering---which is what you use a post vise for anyway!  (Some very expensive machinist vises are made from tougher materials like the wilton bullet vises; or are HUGE like the old chipping vises that weigh over 100#!)

Frankly I buy tools to use; not enough room in the shop for things that "look neat"...

I wonder vises like that we’re built for lighter work like tin smiths or possibly leather working,

I wish you were closer to me I would trade a complete post vise for this vise, I can’t ever seem to find a decent one like this, have a pile of other vises . 
 

Fastenal an a pallet could work wonders!