Here are spiders made by some learners brought to the raker-saw course I ran in May 2018 with Dolly Chapman. If you do make a wooden one, check it frequently as humidity and temperature changes will alter it.
Here is Will Wall talking nonsense about spiders, with Dolly Chapman following up with more sense.
Here is an un-marked spider – we cannot see how many thou of an inch it is.
And if you want to buy spiders, go here in my shop.
You might like to mark your spiders showing how much set they have – here is a video showing one way to do that.