Y'know, if you really cannot get great results using a rest on a regular Grinder (which you should work towards), I would suggest finding and using what is generally called a carbide grinder, in the interim.
The wheels on a Carbide grinder are face mounted, and generally there is a groove on the tool rest for an angle or protractor guide, in addition to the tilt of the table/rest at each end of the grinder.
The Carbide Grinder were originally meant to turn Brazed Carbide bits in to useful tools (something most sellers of such fail miserably at explaining!) but they work a right treat if you utilize them to rough out and finish,basic angle grinds on say, HSS threading tools, or the like.
So far, the best combo I have found,is to have a decent wheel on one end of the machine, that I can rough out the HSS with, and a diamond grit wheel on the other end, set a little wee bit at a lesser relief than the roughing end, that will allow a touch on the tool that gives it a razor sharp edge, and a mirror finish. Yeah. Diamonds and Steel. It works, if you do it right!
If used for actual carbide grinding, that would be a green wheel on the one end, and the same fine Diamond at the other. For HSS use a grey wheel. Grit isn't as important as availability, as the diamond wheel provides the actual finished cutting edge.
And yep, it flies in the face of "what is known". But it is what I have found works VERY well, as a means of grinding lathe tools that cut like they are scary sharp! Or sharper!
I taught my apprentices that the reason HSS is what it is, "HIGH SPEED STEEL", is that it takes a considerably more intensive heat regimen to soften, than the tools of old, and that getting the tool bit red hot, was not going to affect the capabilities in the least bit! Do some reading on the heat treatment and annealing of HSS, and you will soon become a believer as am I!
I taught my apprentices that the bucket of water near the grinder, was to cool their Fingers, not to cool the blank you were grinding!
My standard HSS grinding demo, was to clamp a bit blank in a pair of Vice-Grips, and have at it until it was well past red heat! Grind the SOB, like it owes you money! A LOT of money!
Per above, about fingers, plonking a hot HSS bit in to cold water, is not the best thing to do. Microfractures may form on the surface, which "Might" cause early failures of the cutting edge. But if you allow the tool to cool on it's own, it will just be ugly. Ugly can be fixed by a quick surface level grind (ie: not very deep!). This gets you past the surface level cracking that may have occurred.
HSS is actually wonderful stuff, if you learn where it fits in the Grand Scheme!
I will endeavor to post pictures of my favorite tools. The most usual one was a combo Boring, Facing, and Turning tool that were all only a wee step away from making a internal threading tool.
Depends where you drew the lines on the Tool Blank.
My Favorite question of my Apprentices (all of whom I am proud of!).
Do you have a Sharpie Marker?
We did a lot with Sharpies. Whether it was a drawing on a piece of paper towel, or drawing your intended results on a tool bit blank!