Drywall supply store? Never saw one of those. How can it compress without crumbling the wallboard?
Ron

I've looked at most drywall places in Toronto and online and cant find them. They just sort of compress the board's edge slightly to let the tape seat nicely. Haven't seen them tho in 15 years.

these are normally barrel shaped rollers, not a 'V' taper. they are used to roll seams and edges of wallpaper.

So it was used on butt seams to roll down the fuzzy edge? I have always just used a sharp knife to pare the paper off if the edge is that bad. Nice to know someone came up with a gratuitous tool to roll the edge down prior to taping. You could probably make one from some other tool, a seam roller as suggested; turn a new wheel out of boxwood with the desired taper.
Casey

That's an interesting tool - did you have to moisten the drywall for it to crush and conform to the taper shape of the tool? I found a tool on the web that's designed to be used as part of a process of forming butt joints over a backer board between framing members instead of screwing the drywall edges to the framing. They provide studies, testamonials, the works.

A curiosity. http://www.butttaper.com/thetool.htm

That is an interesting tool. It seems that you need quite a bit of leverage to push that tool. They described using your leg. What they didn't show was how you are supposed to get that needed leverage when you're 7 or 8' up on a stepladder.

Butt taper

Butt Taper, huh? Anybody actually use it? Based on their website clips it looks like overkill. They say it's faster, but I don't see how.

I found a way to deal with butt joints: After placing the tape on and a thin coat over, I place two side coats. This provides enough lift to coat the tape in the middle. I repeat with two more side coats and a middle coat if needed. The joint ends up being about 18" wide and is obtained with only a 10" taping knife. Pros will use these super-wide knives to get this wide joint but these wide knives are pricey and also are hard to control.

Here is a link that might be useful: Butt Joint Procedure

Creating fractures in the gyspum core to make a taper is a great way to weaken a wall.
There are a number of systems available that provide some clearance to allow springing but joints to speed finishing without breaking up the core.

As for the ButtTaper, notice also that the joints shouldn't meet at the stud according to their method so as to leave room for gluing a backer behind the joint. Ridiculous.

Brickeyee, which systems do you mean (that are any good)?

Did you ever find the tool? Because my hubby is looking for one.

https://www.youtube.com/watch?v=tjdFXjmUgzQ

See Jane Drill explains how to use Strait Flex Butt Tape:

Strait Flex Butt Tape Application