Grinding question

R

RAGS

Joined
Jul 11, 2000
Messages
534
I see some makers grind the blade before heat treat,some grind after heat treat.As someone who is totally new to the subject of knifemaking,I would think it would be easier to grind the softer,unhardened steel.What advantage is there to grinding after heat treat?Thanks.
Kevin
 
i always have trouble grinding them so i do it after.(it goes slower and gives more controll)also if you rind incorectly before ht your blade can warp :mad:
only happened once but it did sure ruin my day. so in conclusion i would ht flat and then grind after with nev sharp belts :)
 
Because I'm cheap and lazy, I grind very close to finished tolerance before HT. Just a little decarb removal and final finish and I'm home. But it's true; warped blades can really ruin an otherwise nice day. They make good throwers. :D
 
I used to do it before..............now I grind them after.

MOSTLY, because it is so time consuming to grind a whole batch of knives to send to Paul Bos.

If I just profile them and send them off it doesnt take more than a day.

I have also found that they come back a LOT straighter if I leave the grinding til after. That is no fault of Pauls, but rather the inherent stresses that are built up in steel from the pouring and rolling out of the stock, precision grinding, and finally the inept knifemaker trying to make two grinds that are symmetric on both sides (doesnt happen, but we all try to make it as close as we can!)

:p
 
I grind before HT, then normalize (take stress of grind) , while blade is hot around 700 C get the blade straight using a modified (only for this purpose) vise (act quickly not leting the blade cool down) , let it cool slowly , Heat Treat, then fine grind and then polish... This way i managed to get my best results and i think this procedure wont change for me (except if i get a higher alloy steel i would skip pre-grinding).
 
I forge and heat treat 99.9% directly from the forge after forging to shape, the only grinding is to correct the profile. After heat treating I do a vinegar etch to get rid of the scale. Gib
 
Ahhhh.....blade warping.Didn't think of that.Thanks for the info guys.
 
I rough grind before heat treat. If you wait until after, obviously you will be using more grinding belts. Still, a lot of makers do grind after heat treat.
 
I grind to within 95% of finished dimentions and usually upto a 320 grit before HT, except on my folders. I grind my folders after HT. But having molten salts is nice for that 320 before HT, just rinse and temper afterwards, no scale.

I have never had much of a problem with warping, but I do triple normalize my damascus before HT. On double edged daggers, I have seen some distortion, so I will need to leave a bit more on those before HT in the future.

Grinding after HT is nicer, but slower since you have to make sure you do not ruin your temper from the heat build up during grinding.
 
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