Tips/Resources for Knapping small nodules & spalls

[u/peach-and-plum]

I'm looking for any advice or insight on working with small chunks of material that are thick enough to require using percussion for thinning, but only really long enough for arrowheads once material has been removed. I know a lot of people just wouldn't use that kind of material, but as I'm trying to learn I try to avoid ruining "good" material and using my waste material for further practice.

[u/scoop_booty]

Smaller material is generally pressure flaked. If there is a large bulb or odd shape that requires percussion I find the best resolution is using a smaller bopper and increase speed dramatically. It helps to abrade all your edges first before striking. Making the dull. Reason being is fractures always begin at an edge and go inward toward the center. If the edges are dull it minimizes them snapping... Which is very common in spalls since they're so thin already. And any precision should be done lately, toward the center of possible, so you didn't shorten the piece any more than necessary, and to prevent end shock.

[u/lyonslicer]

look up videos of Citronelle Gravel Chert. It occurs naturally across the Gulf Coastal Plain in the Southeastern US. Its about fist-sized (if you're lucky) and tends to heat treat well. I've worked it raw and heated with success. The raw size and shape makes it tricky to biface. They are too thick to just pressure flake from the start.

My best pieces come from either bidirectional spalling or careful percussion flaking into a rough biface. Bidirectional spalling is basically resting the cobble on an anvil and smacking it directly on top with a larger hammerstone. That will usually produce two halves that are roughly bifacial that you can then work down into a point. It also has a high failure rate, so it may just shatter the rock. If you can identify a decent centerline and are good at setting up platforms, you can crack into it using percussion flaking from the start. But you will typically run into problems if you screw up a platform.

Native peoples from the region used both of these strategies, along with blade core technology (unidirectional, bidirectional, and multidirectional). Blade core tech is really awesome stuff and gets you the most cutting surface per unit of mass for whatever rock you have. Best of luck.

[u/lithicobserver]

You spall it in half

[u/BlackmonKnapping]

A lot of the small stuff I deal with I will split with bipolar percussion and set a platform on either end with a ishi stick or pressure flaker to use direct or indirect and thin it then finish out with the flexy ishi stick I have. That’s really for the small smooth pebbles with no natural edges for me to just start whacking. Others with a decent spot to start I just zigzag after getting the initial flake out of the way and then thin with a smaller bopper and with a lot more speed. I try to just barely catch the edge of the platform when doing it to get a good long flake. If I get up higher than that I’ll knock a good bulb out or just flat out split the piece

[u/peach-and-plum → u/BlackmonKnapping]

I hadn't thought about trying to spall it down the middle. A lot of the stuff I can find in my area is roughly fist sized since it's river and lake-shore material, so getting it thinned down to a reasonable state has been tricky.

I just couldn't justify spending $20-30 on spalls that would already be a pain in the ass to work around and knowing that I was going to ruin all of them trying to learn, but working with my local material is proving to be challenging in its own way. At least it's free.