Question about pre-heat treat finish

[JLaw]

Morning all,

How fine of a finish do I have to sand the blade to before I send it out for heat treat? I've got several blades ready, all 440C, some have been sanded up to 220 grit, one to 400 grit, and I'm working on the last one with 120 grit at the moment. Just curious how fine I need to go before sending them out. These blades will all end up with a satin finish if it makes a difference.

Thank you,

JLaw

[NJStricker]

It depends on what equipment you have available to you. If you are using a 2x72 grinder and have a wide variety of belts at your disposal, then 220 or 320 is probably fine, especially if you plan to remove a lot of metal after heat treat.

On the other hand, if you are a hobbiest that is doing a lot of hand sanding, then you'll want to get it as close to finished as you can. 400 grit should be fine if you plan a satin finish, once you get the knife back you can hand sand 400-600-800-1000. Sanding hardened steel is a lot more work than hand sanding annealled. Make sure you have a good even finish with all the scratches out before you send it out to HT.

[SBuzek]

Joshua
I usually take mine up tto 400.The more you do before H/T the less you have to do after,and gettin scratches out of SS is alot easier before H/T.Then when you get them back all you need is a little clean up.
Stan

[Ray Rogers]

Need is the operative word in your question. I think Armory addressed that very well. What Stan says is true also but a lot depends on what you get used to and what you are st up for.

For instance, I make a lot of 440C blades. In most cases I don't do any grinding or finishing at all except for the basic profile until after all the HT is done. I started doing this in my early days as a way to control warping (nearly eliminates it). It also controls any decarb or pitting problems since pretty much all of it gets ground off when I grind the blade. I'm not trying to say you should do this, I'm just illustrating that you don't really need to worry about how much finishing you do before HT if you learn how to grind on hardened steel ....

[Arccher Moon]

What about file work? I have read both ways and I have done some file work on HT. Very hard! Really nice finish, but hard. How far should I go on the gritts to finish the file work? I got to 320. All the work is done by hand with files and sandpaper.

[Ray Rogers]

I do my filework before the HT and will usually finish to about 400 grit. After HT, I sandblast the filework at low pressure to clean up the low spots and then refinish the filework at 400 until any pitting that may have occurred during HT, and the sandblasting, are removed from the high spots. If the filework needs to be touched up after the finish sanding it's not too hard to do at this point. Also, the sand blasting makes a good surface for sticking lamp black or epoxy or any other form of colorant you might want to use to add contrast to the filework ...