Another handle gap question

[Vincent Price]

I've done a search on the forums here and read through them on the subject. Also watched a ton of YouTube video. For the life of me I'm still having issues with gap between tang and handle. I have a 2x42 belt grinder with a 6" disc on the side, also have a granite surface plate that I'm using. I put a ceramic plate on the platen and have been grinding vertically with a welders magnet attached. I get it fairly close and apply more dykem blue and then sand in a figure 8 motion on the surface plate. But I am still getting a small gap on most knives. I actually ground a 2 inch thick piece 1075 over the last two days to unusable chasing a few gaps. I've heard about hollow grinding the middle of the tang and just flattening the edges, I dont particularly like that idea as I want to improve and not find a cheat way to get around it. Two questions then.:

1. How would one go about hollow grinding the center of the tang with minimal tools? I don't have much to work with until I can afford to buy more.
2. What other ideas may anyone give me to improve the gap issue? This seems to be one of the last holding points for me to be able to turn out a decent knife.

 

[SS369]

Hi Vincent.

Are you sure that the gap is caused by the tang not flat, or is it the scale material.
Where are the gaps, at the front and rear? or in the center?
With some thin blade stock, the magnet can actually hold the blank flat and then when it is off the magnet the curve remains.

 

[Fallbrook Forge]

Pictures might help.

but grinding a hollow in your tang ain’t cheating bud.

use the top wheel on your 2x48. Drill a bunch of holes down the middle of your tang, then run those holes along the top wheel until you have a nice big hollow in the tang.

make sure tour handle material is flat and not moving.

 

[Vincent Price]

I run the scales along the granite slab until they are flat. They are generally pretty easy to flatten and double check by holding them up to the light held together. The gaps generally are in the front or the rear and not the middle. I seem to have the same issue whether I forge out a blade or cut one out.

Hi Vincent.

Are you sure that the gap is caused by the tang not flat, or is it the scale material.
Where are the gaps, at the front and rear? or in the center?
With some thin blade stock, the magnet can actually hold the blank flat and then when it is off the magnet the curve remains.

Hi Vincent.

Are you sure that the gap is caused by the tang not flat, or is it the scale material.
Where are the gaps, at the front and rear? or in the center?
With some thin blade stock, the magnet can actually hold the blank flat and then when it is off the magnet the curve remains.

I run the scales along the granite slab until they are flat. They are generally pretty easy to flatten and double check by holding them up to the light held together.

Hi Vincent.

Are you sure that the gap is caused by the tang not flat, or is it the scale material.
Where are the gaps, at the front and rear? or in the center?
With some thin blade stock, the magnet can actually hold the blank flat and then when it is off the magnet the curve remains.

Hi Vincent.

Are you sure that the gap is caused by the tang not flat, or is it the scale material.
Where are the gaps, at the front and rear? or in the center?
With some thin blade stock, the magnet can actually hold the blank flat and then when it is off the magnet the curve remains.

 

[Vincent Price]

I'm trying to figure out how to upload a picture. I'll give it a Shot with the hollow grind. I generally get the handles pretty flat I think. Atleast cant see any gaps when holding them together at the light. I'll get a picture uploaded as soon as I figure out how. I've literally drove myself crazy over this for the last month. So much so that I'd give making up if I didnt love it.

Pictures might help.

but grinding a hollow in your tang ain’t cheating bud.

use the top wheel on your 2x48. Drill a bunch of holes down the middle of your tang, then run those holes along the top wheel until you have a nice big hollow in the tang.

make sure tour handle material is flat and not moving.

Pictures might help.

but grinding a hollow in your tang ain’t cheating bud.

use the top wheel on your 2x48. Drill a bunch of holes down the middle of your tang, then run those holes along the top wheel until you have a nice big hollow in the tang.

make sure tour handle material is flat and not moving.

Pictures might help.

but grinding a hollow in your tang ain’t cheating bud.

use the top wheel on your 2x48. Drill a bunch of holes down the middle of your tang, then run those holes along the top wheel until you have a nice big hollow in the tang.

make sure tour handle material is flat and not moving.

 

[A.McPherson]

Use the granite slab on your tang. Get it close with the grinder then switch to the slab.

 

[Vincent Price]

http://imgur.com/a/sqp9Ypc

Pictures might help.

but grinding a hollow in your tang ain’t cheating bud.

use the top wheel on your 2x48. Drill a bunch of holes down the middle of your tang, then run those holes along the top wheel until you have a nice big hollow in the tang.

make sure tour handle material is flat and not moving.

 

[Vincent Price]

Use the granite slab on your tang. Get it close with the grinder then switch to the slab.

I sanded one like that the other night for 6 hours and still didn't get it but I'll try some more elbow grease.

 

[A.McPherson]

Lower grit paper, sand before heat treat.

 

[Stang Bladeworks]

If you have the funds a sga will elimate those issues.

 

[FredyCro]

You should be able to get the tang reasonably flat on the grinder. Maybe try a work rest and a squared piece of 2x4 or angle iron. 120 grit ceramic, light pressure and swift pull motions (kind of imitating the sga).

N Natlek says he can get within 0.05 mm like this.

Practice on scrap.

 

[Fallbrook Forge]

Picture isn’t working for me.

my check for the handle material being flat, is that they stick together, at least a bit, when they’re dry.

flatten scales, clean and dry them, and then I’ll lay one flattened surface on the other and I should be able to get them to stick together.

are you drilling holes in your handle material to make space for epoxy?

 

[Hubert S.]

I run the scales along the granite slab until they are flat. They are generally pretty easy to flatten and double check by holding them up to the light held together.

I normally use a straight edge (the thin blade of a small machinist square) and slide it along the scale when checking for gaps against a light. The scales put together could easily block all the light even if there are huge gaps along the edges.

I have the same issue flattening material on a granite block using figure eight motions as you do, particularly on soft materials. I always seem to put more pressure on the leading edges and round them over slightly. Marking the bottom using a pencil for wood and dykem or sharpie for metal has helped me see what's going on. Something else I find helpful is to superglue a small block of plywood to thin items as a handle (use two layers of blue tape in between so the plywood comes off easily). For long narrow items I get better results moving back and forth instead of in a figure eight. It probably takes a bit of practice to get good at it, and I don't have enough. The best results I have achieved so far were on hidden tang knives, closely followed by black micarta scales glued to the tang using epoxy mixed with graphite.

 

[John mc c]

Whichever method you use dry fit them until you see no gaps,clamp up even,only when you see no gaps redo with epoxy

 

[john april]

it seems like you are speaking about a tapered tang, but that was not mentioned. or is it a flat full tang ?

 

[john april]

if its a tapered tang, which i think it is, i used to do those by hand too. the problem with the welding magnet is its easy to press with more pressure on one end of the tang than the other, which ruins the flat you are trying to achieve. i would rough the taper with a big magnet, then when i was almost done, i switched to a small magnet, the bubble jig fixture. its so small you cannot really apply more pressure to the front or back of the tang. its like 3/4"x1/4". put it right in the middle of the tang. use 120 grit and kinda slow on the belt speed. i also find when flattening scales on a granite plate on a sheet of sandpaper, if i take my scribe , push it right into the center of the wood 1/16" of an inch, and use the scribe to move it in a figure 8 pattern, you are much less likely to put pressure toward one end, and it will come flat easier.

 

[scott kozub]

Don't forget that when flattening a scale on granite plate the paper can bunch up ever so slightly at the edges and round them over slightly. The same happens on a flat platen. That's why I like to flatten with the tip up against the platen but disk grinder is better and a SGA is better yet. Hope to make one soon. This is not an issue if the scale has some overhang from the tang that gets ground off later after being attached. It's more of an issue with removable scales. If the scale is being placed against a bolster its needs to be squared to the bolster before attaching. It's also possible that if the scale has a bow in it, the pressure exerted on it on the granite plate temporarily takes out the bow when sanding. If your pushing hard to make the sanding go faster this is causes issues with bunching of paper and removing the bow from the scale. Then once the pressure is released it bows back so a light touch is required when getting close.

Another "cheat" is to use a coloured liner and dye the epoxy. You'll never get a perfect match in colour but it will be so close you'll never notice. If you do notice then there way too much of a gap, to begin with, and the scale was too warped to be applied in the first place.

 

[weo]

grinding a hollow in your tang ain’t cheating bud.

+2 on this. From what I've read you write, this will go a long way to solving your problem. You can do this on either the tang, scales or both.
If your wheel is too big (wide) for the tang you can use just the corner of the wheel to hollow it out a bit. I do it this way when doing knives with integral bolsters.

 

[Natlek]

Fail to correct picture ...........

 

[Vincent Price]

+2 on this. From what I've read you write, this will go a long way to solving your problem. You can do this on either the tang, scales or both.
If your wheel is too big (wide) for the tang you can use just the corner of the wheel to hollow it out a bit. I do it this way when doing knives with integral bolsters.

So you just leave a bit on each side for handle pins?