Making an Accurate Tempering Oven

I used a cheap toaster oven to temper my blades for a while now and was very disappointed in the results. I was only slightly more satisfied with our kitchen oven which is a pretty high quality one.
It was only when making observations with a dedicated oven thermometer that I realised that these ovens, especially the toaster oven, could be out by as much as + or - 20C which is catastrophic when attempting to achieve an accurate hardness.
A steel that would achieve a Rockwell hardness of 55 to 60 at 200C might only achieve 45 to 50 Rockwell at 220C which is no good. Yet my toaster oven, despite being set at 200C would creep up to at least 200C over a short time while a tiny degree of re calibration and the temp could settle at 170C.
It was time to sort this out.
Many thanks to Kostas Kalleris for, yet again, his help with all things electrical.
Music: www.bensound.com
WARNING: This video is for entertainment purposes only. I am in no way qualified as an electrician and do not pretend to be teaching you how to make your own PID controlled oven. Please seek help from a professional before undertaking electrical project.

[@handsofrhythm3415]

I really appreciate the honest approach to your videos, your projects tend to pan out like my own. It's motivating to see you keep plugging on. Thank you

[@Ukenick]

Thanks so much Jaime. Like many of us, I do my best learning when I mess it up and have to try again. All very best.

[@aikabacrafttools9129]

Nice proyect. I've been thinking on doing a dedicated tempering oven myself, but never thought on reusing an old oven for it, really good idea.

[@Ukenick]

Thanks so much. I have to say so far I’m very pleased with it.

[@KonstantinosKalleris]

I was thinking if you finished the oven and here you are! Great job Nick, I enjoyed it!

[@Ukenick]

Thank you so much Kostas. And yet again without your help I might have blown the house up.

[@KonstantinosKalleris]

@@Ukenick I don't believe that, you 're doing fine! Thanks for the mention. You are always welcome.

[@joell439]

Interesting....... including all the details, good and bad. 👍👍😎👍👍

[@Ukenick]

Many thanks. Much appreciated

[@JimmysCanal]

I didn't knew that a simple toaster oven can be turned to such an accurate tempering oven. Very nice project and excellent video, as we always expecting from you! Well done my friend! Dimitris P.S. I belive that you can use this oven for powder coating, isn't it?

[@Ukenick]

Thank you so much my friend. I am very happy with it now.

[@jimkeefover245]

Very interesting plus I never thought of it it will be a very handy thing to know I am greatful for this it is something I can really use thank you very much

[@Ukenick]

Thanks Jim. It really is very useful and not crazy complicated to build (if I can do it...)

[@ratsniff]

I'm not your mum so you can tell me where to go... but you should be wearing a respirator when handling ceramic blanket - and it definitely shouldn't be exposed on the inside like that. That stuff is no joke. All the best.

[@bigoldgrizzly]

Perhaps butcher a car trailer socket & plug to isolate the controller from Oven ??

[@materroad640]

what is the right temperature for car wheel bearings or motorcycle wheel bearings for tempering in knife making ,tanks

[@Ukenick]

Hi and thanks for getting in touch. That is a very difficult to answer with any accuracy as each steel has different properties and also it depends on the final hardness you want to achieve. Typically wheel bearings are made from a E52100 steel. You might want to research it. The recommended temper would be between 150C and 180C probably for an hour. This is my opinion but may be wrong. Good luck anyway..

[@materroad640]

@@Ukenick thanks for the answer, i like your opinion. have a nice day