To explain it a little further, as Oz explained, this will soften the steel. As Raker expressed, most, if not all steel available from the knifemaking supply houses is usually, if not always annealed or softened. When heat treating is referred to, it generally means that the steel will be hardened and then tempered (or for the want of better term, stress relieved).
If you want a stainless, 440C is probably a good choice. It is fairly easy to work with and will take a good mirror finish. There is also ATS34 (or 154CM which is essentially the same steel) which is a little harder to work with. There is CPM440V or CPM420V which are extremely hard to work with and will not take a mirror finish. All will need to be heat treated.
A semi-stainless, D2 is a very good choice.
Now as far as the carbon steels go, I am not nearly as familiar with these but......
there is 5160 which is old leaf springs in older trucks. There is L6 which the large sawmill blades were made out of. There is 52100 which is or was used to make ball bearings out of. There is O-1 which is quite common and also 1084 which tends to be fairly forgiving. If you want carbon steel your biggest challenge is finding someone to heat treat it for you.
Carbon steels are usually forged, stainless steel knives are usually made using the stock removal method with files, sandpaper, grinders, sanders or what ever method to shape the blade. There are quite a few places equipped to heat treat stainless. Not so many with carbon steel.
Below is a list of knifemaking supply houses, steel suppliers and heat treating services. You can order your steel from any of these. I would recommend probably 440C for a first attempt unless you want carbon steel. Then maybe 1084 or O-1.
Texas Knifemaker's and K&G have the ability from their websites to download their catalogs.
If you really are intending on making a boot knife, check the legality in your area. In most, if not all states, it is considered to be a concealed weapon if carried. You really don't want "that" on your record....
Steel and knifemaking supplies
Downie Knives downieknives.downie.com
10076 Estate Dr.
Port Franks, Ontario, Canada N0M2L0
Tel: 519.243.2290
Jantz Supply
http://www.jantzsupply.com/
P.O. Box 584 email: jantz@brightok.net
309 West Main
Davis, OK 73030
Order Line: 800-351-8900
Phone: 580-369-2316
K & G Supply
http://www.knifeandgun.com/
P.O. Box 458 Mail Stop I. email: sales@knifeandgun.com
Lakeside Arizona 85929-0458 email: info@knifeandgun.com
Information (520) 537-8877
Fax: 520-537-8066
Order Line: 800-972-1192
Sheffield Knifemakers Supply Inc
PO Box 741107
Orange City, FL 32774-1107
cust serv 1-904-775-6453
fax 1-904-774-5754
Texas Knifemaker's Supply
http://www.texasknife.com
10649 Haddington #180 email: jimll@hal-pc.org
Houston, TX 77043
Phone: 713/461-8632
Toll Free: 888-461-8632
Fax: 713/461-8221
Tru-Grit
http://www.trugrit.com/
760 E. Francis St. N email: Trugrit1@aol.com
Ontario, CA 91761
Sales & Technical Support: 909-923-4116
Outside of California (orders only: 800-532-3336)
Information - Trugrit1@aol.com
Koval
http://www.kmg.org/kovalknives/index.html
5819 Zarley Street Suite A
P.O. Box 492
New Albany, Ohio 43054 USA
Ph. (800) 556-4837
In Ohio (614)855-0777
Fax (614) 855-0945
Pop Knives and Supplies
James Poplin
103 Oak St.
Washington GA 30673
Tel: 706-678-5408
Universal Agencies Inc.
http://www.uai.org ~or~
http://www.knifesupplies.com
4690 South Old Peachtree Rd. Suite C email: info@uai.org
Norcross, GA 30071-1517
Tel: 678.969.9147
Fax: 678.969.9169
Order Tel. 1.800.864.7824
Rex Walter email: mailto: rexnpam@thesafety.net
637 Portersville Road 52100 in barstock, $2.00/inch, additional
Ellwood City, PA 16117 $1.00/inch for surface grinding down to
about .100 inch as of 2/1/2000
Admiral Steel
http://www.admiralsteel.com
4152 West 123rd Street sales@admiralsteel.com
Alsip, IL 60803 1084, 1095, 5160, O1, A2, D2, 440C, ATS34,
Tel: (800) 323-7055 BG42
Fax: (708) 388-9317
Caffrey Knives
http://www.caffreyknives.com
2608 Central Ave. West Damascus and 52100 barstock made per
Great Falls, MT 59404 order.
Tel: 406-727-9102
Swain Spring Service
contact: Jeff Carlisle 5160, 52100 round stock, 15N20 and
Great Falls, MT 59404 nickel strip
Tel: 800-378-1246
Meier Steel
http://www.meiersteel.com/
Daryl Meier Damascus
75 Forge Road
Carbondale, IL 62901
Tel: 618-549-3234
Fax: 618-549-6239
Simonich Knives
http://www.simonichknives.com/idxtest.htm
Box 278 rob@simonichknives.com
Clancy, Montana 59634
Tel: (406)933-9151 Talonite
Fax: (406)933-8910
Schott Knives
http://www.angelfire.com/ct/schottknives/
Ed Schott shtml?Category=
EdwardRSchott@aol.com
CPM3V & CPM420V
Crucible
Bruce Di Vita
http://www.crucibleservice.com
1101 Avenue H East
Arlington, TX 76011
(817) 640-7777
(800) 365-1168
Heat treating services
K & G Supply
http://www.knifeandgun.com/
P.O. Box 458 Mail Stop I. email: sales@knifeandgun.com
Lakeside Arizona 85929-0458 email: info@knifeandgun.com
Information (520) 537-8877
Fax: 520-537-8066
Order Line: 800-972-1192 Air-hardened steel only (stainless)
Texas Knifemaker's Supply
http://www.siteblazer.net/texasknife/
10649 Haddington #180 email: jimll@hal-pc.org
Houston, TX 77043 Bead blasting
Phone: 713/461-8632 Deep cryogenic tempering (-300 degrees F)
Toll Free: 888-461-8632 Double foil wrap
Fax: 713/461-8221 Air-hardened steel only (stainless)
Paul Bos
1900 Weld Blvd.
El Cajon, CA 92020
Tel: (619)562-2370 Air-hardened steel only (stainless)
Howard Clark email: howard@mvforge.com
Morgan Valley Forge
115 35th Place
Runnells, IA 50237 carbon steels
Gerome Weinand GMW knives@aol.comm
carbon steel up to 24 inches
Allied Heat Treat Ltd
7521 Tranmere Dr
Mississauga, Ontario
Canada L5S 1L4
Tel: 905 677 8000
[This message has been edited by C L Wilkins (edited 10-10-2000).]