Help finding a COMPLETE list of parts for a heat treat oven.

B

Blowtorch

Joined
Aug 15, 2014
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4
Hello all,

Hopefully someone here can help me find a complete list of parts with (part numbers or model numbers) to build a home made heat treat oven.

Example #1: Kanthal wire. What gauge? manufacture? Ohms of resistance per foot?

Example #2: PID controller. Universal? Dual? manufacture? Model?

Some time ago the was a gentleman on Viddler who had made a very comprehensive video about his home made oven. Unfortunately I can no longer find any active links. I believe it was originally uploaded by a fellow named "rashid11". He also had some other really cool videos about belt grinders, lathes, milling machines, etc.

All of my web searches so far have found articles, and videos that are too vague. Not enough info to actually order from.

Any help is appreciated.
 
Great link to some amazing info! Hours of reading ahead of me. Thanks.

I wear many hats, but I would never consider myself an electrician. However I can follow instructions. There is some great questions and answers in that link.

I am new and unfamiliar with how things are laid out here. I will eventually figure it out. I appreciate the help.:)
 
Read and try to digest as much as you can. I am pretty sure you will not find a truly complete set of parts listed anywhere.

I think there are probably several reasons for this.

First is that almost everyone who builds their own does so to save money. Their build will reflect the materials and facilities they have available. Some will have welders, others will bend up a sheetmetal casing, some will rivet and some will use nuts and bolts. Many will buy the elements, a few will wind their own.

Second is that controller technology, like most electronics, moves quickly. A parts list from 3 or 4 years ago may well be obsolete. If not, it's very likely that a newer controller will be available with improved functionality and at lower cost.

Third is that the electrical side of things can differ considerably between countries. An example would be the US mains system having 2 "hot" wires on 220V, versus the single "hot" on European 230V mains. Most US builds seem to use 2 SSRs where European builds only need one. Here in the UK, domestic sockets are designed for 13A and the plugs are fused, whereas most of Continental Europe seems to use nominal 20A domestic plugs and sockets. I have an effective power limit of around 3000 Watts as a result, but just over the channel the limit is around 4500 Watts.

Sizing and elements can make a big difference, as can the required operating temperature and frequency of use. For a hobby maker, 16AWG (1.29mm) elements are a reasonable choice, particularly if mainly working with Carbon Steels. However, based on my admittedly limited experience, element life seems shorter than would be desirable for a professional working with Stainless steels and needing to put food on the table. A couple of the ovens I've built have been used by pro makers and failed within a few months. I have since switched to using 1.6mm elements, though still in Kanthal A1. The thicker wire has lower resistance per foot/metre and therefore a greater length is needed for a given output. I've needed to make some design changes to accommodate this.

Many homebuilt ovens have been based on Andy Gascoigne's pdf writeup originally posted on British Blades, including my first 2 or 3. I think it is a very good starting point, but would strongly recommend bringing twisted element tails outside the oven, rather than using the stainless allthread through the wall.

I feel anyone building an HT oven needs to have a pretty good understanding of both the process and the equipment. I'd actually be quite worried by a set of instructions that was written to allow someone to build one without that understanding.

All the ovens I have built are currently with folk who'll actually use them so I cannot just look at one and write a checklist. Off the top of my head though, this is a list of the things that I can remember, with some of the factors that will affect the choice in brackets.


HT Oven Parts List

Control Box:

Enclosure
PID Controller (Ramp/Soak preferred)
SSR(s) and HeatSink(s) or Contactor(s) (to suit PID controller output, element current and local/chosen power supply system)
Mains cable
Plug(s) (to suit local power supply system)
Possibly RCD/GFCI to suit local power supply system
Equipment wire for internal wiring.
Terminal strip, labels, crimp connectors, cable ties, etc.
Switches and/or lamps/indicators (to suit control design)


Oven:

Frame/casing (to suit builders available equipment/materials)
IFBs (or other appropriate insulating refractory materials)
Elements (to suit oven dimensions, materials of construction, desired working temperature range and power supply)
Element retainers (to suit elements and chosen retention system)
Element connectors (to suit termination method chosen)
Power cable from SSR(s) to elements (to suit the termination method chosen; may or may not need a high-temperature cable)
Door hinges.
Door catch (this needs to work with one hand if treating more than one blade at a time)
Thermocouple (type to suit controller, remaining details to suit the detailed design of the HT oven)
Compensating or extension cable for thermocouple (may or may not be needed, depending on detail design)
Door switch (to suit current and Voltage being switched)
Door switch cable if needed.
Levelling feet or similar.


If using a separate standalone control enclosure:

Plug(s)/socket(s) for power connection(s)
Plug/socket for doorswitch
Plug/socket for thermocouple
 
Thank you so much on such a comprehensive response. This is what I hoping for.

I live in the USA and therefor a 240v system is what I have. I will probably only deal with one knife at a time so I can build a smaller oven. With the larger knives in mind. Such as as large Kukuries, and Cleavers.

The points you made concerning newer materials available make sense. I'm just trying to make a basic, yet safe model to use. Money of course is an issue, but I will buy the best materials I can.

I have a lifetime of dealing with fabrication. I own a plasma cuter, wire feed welder, oxygen/propane torch, lathe, milling machine, drill press, grinders, and various other hand tools associated with metal fabrication. If you can draw a picture, I can most likely build it.

Still I make no claim of being an electrician. Yet I can follow diagrams.

I have been reading and conceptualizing an oven for a few years now.

The materials I will most be using for knives are, 1080, 1095 series steel, 5160, and CPM S30V steel.
 
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Your first three steels will be no problem with a home made oven. The S30V will take more precise HT, and a better oven.

I often tell folks that the building of an oven is a project for those who need a special oven. If you want a general use oven. buying one is often the best spent money. For your needs, an 18" deep knifemaker oven will do nicely. It comes plug and play with everything you need.
 
The oven was primarily for the S30V, and if a home built oven won't do the trick then it's all for not.

Which begs the question: Why would my home built oven be lesser in quality, and function than a much more expensive store bought one?

A lifetime of fabrication has taught me one undeniable truth. Most products used by humans were made by average people just doing their job. With basic instruction and a little practice, amazing things can be built. Throw in some good tools, and an eye for detail. You can fly to the moon. :friendly_wink:
 
A lot of it is down to development. The Evenheats and Paragons of this world have far more experience of this sort of stuff than you or I as their starting point. They are also in a position to put prototypes out with selected expert users and get their feedback before starting production. Then, as improvements become possible/necessary, they can be incorporated into the production process.

For most homebuilders, the prototype is the only one they'll ever build. Improvements will only come when something breaks, or when a deficiency is so apparent that the builder simply cannot live with it.

The difference between a really good product and a mediocre one is usually "just" the fine detail. Spending years doing a particular thing gives one an eye for the minutiae that is way beyond anything a novice can match. It's as true of thermal processing equipment as it is of bladesmithing or violin making. Realistically, you are very unlikely to better a Sebenza with your first folder, nor are you likely to better an Evenheat/Paragon with your first HT oven build.

That said, with diligent research, good attention to detail and a good ramp/soak controller (I use the Omega CN7823 or the AutomationDirect Solo SL4848VRE, which are basically the same instrument, but a lot of folk stateside use the Auber SL2352P), S30V should be no problem at all.

In the USA, I'd be inclined to agree with Stacy: the differential between the cost of the parts to build a quality HT oven and the cost to buy one is not huge; buying one seems to make sense. Here in the UK, the differential is much greater and this skews the buy/build argument somewhat.
 
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