This is a conversion inspired by a number of Space Wolves miniatures and dreadnoughts that I've encountered over recent years.
For my Alpha Legion dreadnought, I wanted an option that looked simultaneously both deadly, and like it had been "borrowed" (ahem) from other legions, or xenos technology that has been reverse engineered. When I set eyes on the True Claws of Bjorn, I thought that I had the mark!
In the image, I've combined the fingers of the Trueclaw with the arm of a resin contemptor from Forge World. Each of the fingers had to be shaved down in terms of their sheer width to fit the slots in the contemptor's terminus, and each has been pinned in place with a paperclip wire to the knuckle of the contemptor's resin.
The fingers are spread out to reveal a flamer head and pilot flame in their centre - an aggressive pose that combines that "flame that enemy" with "going to claw you" deadly pose that I was gunning for. What remains is to magnetise this claw and see how it looks on one of my contemptor dreadnoughts.