roller nut difficulties

Hello everyone,

I want to make my first medieval crossbow. The difficulty i have is making the rolller nut.
What can i use for suitable steel does anyone know where i can find such a large piece of steel?

I also thought about making one of hard wood, how much pound can it hold?
Maybe i can make one from a lamination from pieces of hard wood and steel plates and pin and epoxy them together.

thanks in advance

Steel = NO. Too heavy.  Back in the day roller nuts were made from very hard woods, often from root swirls so here was no linear grain.  They could stand a couple hundred pounds at least.  You could use ebony or African Blackwood, or Lignum Vitae.  Not European woods, but very, very dense and hard.  The other material that was used was the boss end of large antlers like moose or elk.

Thanks for your reply.

In some pet shops they sell pieces of antler maybe i can use these.
Can i use any piece of the antler or does it has to be the end part?

What they sell in pet shops is usually cow bone slices.  Much softer than antler.  Unless you live where there are MONSTER moose, you need to use the end because that' where you'll get enough antler to do the job.

Cream colored hmwpe is polyethylene and very strong, not heavy considering its strength.
This material is readily available and used in hip replacements. The horn is still better in the long run.

Thanks for the polyethylene recommendation i would never have thought of that. They sell fallow deer and red deer stag at the pet sore which one do you think is the best?

Welcome Kruisboog, i made my last nut out of a bronze or brass weight, relatively easy to work with, you might be able to buy one from a hardware store.

Roller nut materials: There are plenty. For cost and efficiency, I normally use Delrin (polyethelyne) for the nut, 1 and 3/8 or 1 and 1/2 in diameter will work fine, if you put in a steel plug for the trigger to work against.  The best quality medieval hunting bows usually use antler (not cow-horn) I find Moose-stems work very well.  Axis stag is good too if you can get bits thick enough.  Elk horn tends to be very pithy in the middle, so doesn't make a good roller.  If you're working at less than 100 lb. a good hardwood like maple or oak will give years of good service (again, you need a hard point, brass or steel for the trigger sear) My very first crossbow used a brass nut.  Its fairly easy to work and looks snazzy, but the stuff is very heavy... the slow turning will contribute to misfires, though drilling a few lightening holes should help.  A solid brass or steel nut probably won't need a reinforced hard-point for the sear.  If you're working from Payne Gallwey's plans, I recommend you make your nut socket a bit deeper than specified.  He sez to sink it 3/5 of diameter, but 2/3 is more secure.  Have fun with your build.  Geezer.

PS: I generally don't use Delrin for a roller nut, even with a steel sear if the bow is much over 150 lb.  That's when I go to moose horn.  Geezer.

If you decide to use wood you can use a hole saw like this one (the one in the pictures is 1 1/2" wide, the wood is walnut root)


you can also use an adjustable drill bit like the one in the next picture to bore the side of the wood to fit the nut snugly (mine goes from 7/8" to 4")

Just to clarify, hmwpe and Delrin, a brand name for polyoxymethylene, are two different types of high strength engineering plastic. I've used both without issue with prods up to 220 lb draw weight, with steel sear inserts. Delrin is a bit easier to work in my opinion and you can get a glossy finish, but the hmwpe is available in more natural colors, like the cream. So far I've only found Delrin in black or white.
Gnome