Need Advice/Information

M

Maple_Forest

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Jun 9, 2015
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Hello, I just joined the forum because I have been lurking around these boards for a while now and I am beginning to run into problems concerning knife making.

The most significant of these problems is merely a lack of information (at least I can't find what I'm looking for). I am seriously considering building a homestead that will largely be off grid except for some solar power to charge my laptop and a few other small electronics that don't require a great deal of electricity. Now I want to make knives while I am living on this homestead and while I could always learn to forge, stock removal is what I have done so far and I like it. The only problem is that after the heat treat when the blade needs to be tempered (usually I do this in a toaster oven). However I will not be able to run such a demanding electrical appliance for the amount of time to properly temper the knife. Already I am going to be using a filing jig instead of a grinder so the process will be a bit slower, but I am used to filing by hand.

So I am desperately searching for information on how to properly temper my knives in a forge or something that does not require electricity. However I can't find anything about how to do this. How hot it should get, how long should it be in the forge, etc.

How did people do this before modern appliances? Any help would be appreciated.
 
Welcome to Shop Talk. Filling out your profile and giving us some info on you and your plans will help us give better answers.

What you ask is pretty standard info, and part of it is in the Stickys. Most blacksmith and forging sites have lots of info on tempering with a charcoal forge. It basically entails using a block of iron/steel heated up to dull red, then removed from the forge. You run the spine of the bright sanded knife up and down the hot block and watch the temper colors run down the blade. Dip in water as the straw/bronze color reaches the edge. Repeat several times until the blade is evenly tempered. This isn't nearly as good as two oven tempers, but will make a usable blade.

A study of books and videos of traditional Japanese smiths will show that they do all their work without electrical power. They use a bellows box to run the forge, files and water stones to shape and polish the steel, and a method like the above description to temper the blades. The forge is the heart of the shop, and all other tasks take place around it. This also provides heat to the shop in the winter.

Many knifemaker folks are off the grid. Some have a diesel/gas generator they run when they are in the shop and have all the normal items. Others have solar arrays that run the equipment by day, and charge batteries for power use in the house during the evening/night. If the cabin will be more of a vacation spot, and you will return to the powered world part of the year, consider doing all the pre-HT chores on knives at the cabin and the HT and finishing at the powered shop.

If going off the grid and making knives are to be combined, making a charcoal oven will be a good idea. It will turn wood into charcoal.
Also, the internet may not be available off the grid.
 
My apologies, I will read the stickies. For some reason I was not able to find what I was looking for. Also I will be living off grid full time or as much as possible, an Internet connection is something that I need to provide income so I will be living in a rural area, just close enough to the urban area so that I can still obtain Internet at a reasonable monthly cost.

Thank you for your reply, it is very helpful.

Also, are you saying that it is possible to run KMG size belt sanders off solar? This is all somewhat knew to me so I still have to figure out how many solar panels I need for my energy usage. This move to a homestead will occur in about two years.
 
A KMG-sized grinder can be run off solar, but then so can pretty much anything if you've got enough panel area and/or battery capacity.

On a practical note, I built one of the cheap Chinese HuanYang 3HP VFDs off ebay into an IP65 (NEMA4 equivalent) enclosure. An off-grid knifemaker in the South-West of England (Latitude 50.7 deg N) has been using it since about last October, as far as I am aware without problems. The motor is 3-phase, 3 HP, 2-pole, 230V.

He had been having problems with his generator bogging down when he used his single-phase grinder and wondered if a VFD and 3-phase motor would help. It did, but he also found it would run off his solar system. He has a 230V Modified Sine Wave inverter, but I'm unsure how much battery capacity and panel rating he has. I was quite surprised the MSW inverter did not cause any issues.

Most big-name VFDs that I've come across tend not to like "odd" supplies. I wanted to try the Chinese one in a real-world off-grid situation because it seemed likely that, compared to the big-name ones, the input side was oversized in order to deal more effectively with supplies that might not be up to Western standards. I'd already found the HuanYangs would run happily off cheap portable gasoline generators where ABB, Siemens and Telemecanique drives often would not.


For tempering, very little heat input is really necessary if the insulation is good. Electrical heating is probably the easiest method and a well-insulated PID-controlled tempering setup could be built quite easily using a rod-type heating element rated for a low output; I'm pretty sure 200W would be enough with careful design and 500W would leave a good margin for sub-optimal design/build. Calcium Silicate (and probably also Mineral Wool) is well able to cope with tempering temperatures, so there's no need to go for Ceramic fiber or Insulating Fire Brick.
 
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