Bits for an older Bosch hammer drill

I have an older Bosch hammer drill. I don’t have the model number handy but can get it tomorrow. I was using it to drill through stone. The bits that I have are about 2 feet long and have a number, something like 10, evenly spaced splines at the end. I went to Home Depot to buy a new bit but they told me they don’t have any. I looked at bits from other manufacturers but none seems to have that configuration/number of splines. Is there a source for bits for an older Bosch hammer drill? Can one of the newer style bits be used in that old drill?

 

I think it’s called “spline shank”. I don’t have the diameter right now.

 

Thanks in advance.

Welcome to the forum.

 

Any chance on posting an image of the bit end that fits into the drill?