sanding questions

SHOKR

Well-Known Member
hey all

i don't have a running KMG (yet) so what i do is use angle grinder with those round sanding sheets (or a file couple of time), so far i used a heavily used 80grit then started hand sanding.

so my questions are, how do i deal with 'curved' sanding, this will be bit hard to explain but i'll try. when the main part of the edge (the part extended from the handle) is straight but the curved up part (near the tip) is so curved that i have to sand at an angle and not just take it as one long stroke from ricasso to tip. i guess sorta like the tanto blade BUT with no definite separation of the main edge and the tip part. i DO hope that makes sense lol

second question, after heat treating i'll finish by hand as well, so someone told me to go up to 400grit before HT to save effort, but what if the minimum thickness to leave before HT (also read is about 0.6mm) is too thick to be sanded with higher grits after HT, do i go lower in grit and start over again or what? or if anyone has a better way of doing it please let me know

i do hope you didn't get a headache reading that!

thanks!
 
Ahmad, are these flat ground or hollow ground blades? Until you are actually doing your post-ht finish sanding, it is not imperative that everything be sanded in one long stroke. And even then, you only worry about that if you are doing a rubbed type finish. For hollow ground blades, I ended up making some sanding block that follow the same arc as the wheel on my grinder. One of these I added a pad of 8-9oz leather to, the other is just the bare wood. I mostly use the wood block, but the leather faced one is handy for cleaning up the plunge area.

As far as your post HT finish, it really depends on your methods. For my stainless blades, I send them to Peters' and pretty well have them at final dimensions. For 108x steel that I HT in my forge, I have had good luck coating the blade with a VERY thin coating of satanite to help reduce scale. Again, I finish close to final dimension if it is a larger knife. For smaller blades with a more delicate edge, I will leave them a little thick and grind down to final thickness after HT.

If I read you post correctly, then I hope this helps... if I didn't. then I probably gave YOU the headache :biggrin:
 
If I read you post correctly, then I hope this helps... if I didn't. then I probably gave YOU the headache :biggrin:

lol well you read most of it right, but i still got bit of headache, i'm new to this, still working on my first knives so bit too much info.

i grind flat, there might be bit of hollow at first but when i hand sand with high grits or draw file i take it out.
i'm currently trying to make knives out of files, i'm treating them as 5160, even tho i'm not so sure about the steel.

i think i'll post a drawing of what i mean, probably will be better

thanks Mark!! :)
 
bladesoutlinedbushbaby0875.jpg thats an example of what i meant, so how curved the bevel is? how is that hand sanded?
 
You should be able to just follow that around with your sanding block. What are you using as a backing for your sandpaper? For flats. I use a piece of hardened steel that has been blanchard ground. It's actually a draw file from brownells, but the back is dead flat. I bring my grinds up higher than that, but I do a lot of swedges that are steeper than what you are showing. You just need to make sure that your block is resting on the grind and not rocking up and blurring your grind line. You may find it to be easier if you brought the grind up high, plus it would improve your edge geometry.
 
for the time being i mainly use old tempered files (the ones i'll eventually turn to knives) like 2 days ago i decided to get a pieces of steel because once or twice teh paper slipped and the file ended up lightly scratching the knife. but havent got anything yet.

i did try to follow once before, but i guess it was too hard for me i thought i must be doing it wrong or there must be a better way

blanchard? whats that? :52:
you mean ground flat with no teeth?


for my knives i actually go with the bevel pretty high, these are WIPPhoto0225.jpg

these are actually the ones i'm working on now, and they my first knives ever!

i guess will give it another try

many thanks Mark! :)
 
Those look good! I dig those kiridashi type knives. I would try to find something other than files for your sanding blocks... You said you have some steel now, so that's good. Thicker micarta and G10 work well too. Hand sanding can be tough, especially if you don't have a grinder to run a high grits first. How are you clamping these down to sand? You have probably seen it, but a lot of us use a long board or piece of synthetic material mounted perpendicular to the bench to clamp the knife to while sanding. The nose is shaped kind of like a long, half ellipse so you can get the edge of the knife close to the edge of the board with out it hanging over and becoming a danger to the maker. Blanchard grinding is an industrial process for making things very flat and parallel. The tool I bought is dead flat on the back with no teeth (it came that way). A piece of good flat steel will net the same results. Keep it up!
 
no i havent got steel yet, but micarta does sound good!

acquiring the desired steels here was less than fruitful :49:

but i will look more into it, does it matter if its stainless steel or anything else? any specifications on size or thickness? i saw people use ground pieces to better wrap sandpaper or better get into the plunge area but thats bit advances for me at the moment

today i got a scrap I (or H) beam, trying to get something like nickwheeler's set up. but my current work bench as i said is a bar stool!sometimes i have to fix it by holding with my legs, not practical i know but since i have no shop yet i work from home (apartment). what i do is fix a flat piece of wood to the chair with a c clamp and most recently tried irwin f clamps. and since i'm mostly working with small blades so far i rotate them just little bit to get the desired effect you said.
so my next step is get harder backing (the beam) and shape it bit U-like. thinking about the having screws to push back the work pieces to avoid the 'flapping'

any idea how to clean the beam from rust without ruining the flatness? i was going to go for vinegar or something, but if you know of something better would be great :)

thanks again Mark!
 
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