convex edges and daggers....

B

brantoken

Joined
Feb 6, 2004
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303
I have been continueing my education and practice on convex edges, I'm having a heck of a time with daggers for some reason. I have got to the point that I can put a nice razor edge on just about any single edge blade , but for some reason the dagger eludes. Is there something that I'm missing
here. it would seem that a dagger would sharpen just like any other
egde except that there are two. Any insights?

I did my first knife kit a couple of weeks ago , I did a chiefs knife. It came out OK. I made every mistake possible and somehow it still came out ok .
The dust was horrible, any tips on dust control. I got a layer of wood and metal dust covering my whole workshop now. Vacuuming the whole place is going to be a real pain..... tips appreciated.....
 
The blade grind on a dagger will be less acute than if the same piece of steel were ground as a single edged blade. Take a sheet of paper and sketch a couple of oversized cross-sections of single and double edged blades, starting with rectangles (bar stock) of the same thickness and width. You will see that the single grind comes to a sharper angle than the double.

My old cheapie Delta belt sander has a vent hole where one can attach a hose, I can attach a household vacuum which will reduce the dust somewhat. Besides that, I don't know what else you can do, dust is also a problem for me when sanding or grinding, I also would like to hear everyone's solutions for this.
 
I just claim to like the dusty, lived in look....

.
 
If you leave it long enough maybe your wife will clean it up, mine does.:D :p ;)
The best thing though is to mount the hose end of your shopvac close to the grinder, saves a lot of dust.

A dagger has a more obtuse or blunt edge than a single edged blade and you have to account for that when you sharpen them by raising your angle a bit or flat honeing them. Flat honeing them produces a single beveled edge like many Puukkos. Super Sharp even with the obtuse angle!!!!:D :D
 
Here's a great site on dust collection:
http://billpentz.com/woodworking/cyclone/DC4Dummies.cfm

The quick version is:
a) dust, especially very small dust (under a micron) is very dangerous to breathe. He's screwed up his health from dust.
b) most vacuum cleaners and dust collectors have filters that let this little stuff through, blowing it around the shop even more.
c) Also they don't have enough airflow to catch *all* of your dust. (He quotes AAF as saying that belt sanders up to 6 inches wide need 450CFM bottom PLUS another 350CFM top. Not sure exactly what top and bottom mean.) Airflow problems are caused by a combination of fan design, motor's power, ducting, and resistance from filters.
d) Most dust collector manufacturers lie by measuring airflow without filters or hoses and measuring minimum particle size when the filter is nearly completely clogged.

It's actually kind of depressing because you feel like need to have a $1000 customized dust collection system to run a $30 sander. I don't think this would be acceptable for a full-time shop. Perhaps a 1-inch belt will do OK with a lower air flow? Perhaps the occasional, light exposure from home use poses less risk? I don't know.

I expect hooking a shop vac to a sander's dust port will help a lot, but make sure you've got high performance filters in it.
 
They even make shop vacs that hang on the wall- ideal for this purpose.

I had my grinder right at the end of the bench- 2 ft. from the garage door, which would be open... fan & sweeping took out metal dust. You don't forget metal splinters in a hurry....

and oh, yeah, they have more expensive filters for the vac that work better with obnoxii.


Ad Astra :(
 
brantoken said:
I have been continueing my education and practice on convex edges, I'm having a heck of a time with daggers for some reason. I have got to the point that I can put a nice razor edge on just about any single edge blade , but for some reason the dagger eludes. Is there something that I'm missing
here. it would seem that a dagger would sharpen just like any other
egde except that there are two. Any insights?

I did my first knife kit a couple of weeks ago , I did a chiefs knife. It came out OK. I made every mistake possible and somehow it still came out ok .
The dust was horrible, any tips on dust control. I got a layer of wood and metal dust covering my whole workshop now. Vacuuming the whole place is going to be a real pain..... tips appreciated.....
Click to expand...


My shop is pretty small, about 300 sq. feet of usable space. I don't have the 220 wiring or the available space to set up a real nice dust collection system, but had plenty of available ceiling space, so I got a Delta Shopmaster that hangs from the ceiling directly over the separate wood working bench I built in the center of the shop area. It has a prefilter and a main filter and does a good job for a small shop. I still wear a respirator when doing major sanding or sawing, or grinding paint / rust off metal or anything that generates a lot of dust, but the overhead filter makes cleaning up a lot easier. I also got a large wand for the air compressor and after working will blow everything off and out the door as much as possible, which saves tons of time over vacuuming.

The Delta retails for around a couple of hundred, but you can do a bit better if you shop around. It moves around 650 CFM I think. I learned not to rinse out the prefilter, but periodically blow it out with air, and then install a new one ever 6 months to a year depending upon how much I use it.

For the table saw I attached a dust collecter basket made by the manufacturer and then ran a 10' hose from the shop vac into the basket. As wood is sawed the vac does a good job of sucking all the dust and wood chips down and into the vac, preventing most of it from getting airborne at all. Sears sells a switch that will power on the saw and the vac at the same time, which is helpful. Other tools like the miter saw have their own bags, but still kick out a lot of dust.

If I could really setup a state of the art shop it would be one of those with a dedicated dust collection system in the corner and duct work running to each tool, so you wouldn't even have to think about it, but that won't happen for quite a while until the day I can move and could build a shop from the ground up!

Good luck,

Norm
 
A couple of cheap box fans (the $10 ones from Home Depot) with the big square air filters (like the kind used in a home AC unit) taped to the front of the fans can help to catch the dust. It helped to cut down on the amount of dust I have had to deal with anyway.
 
What you need to be very careful of, when sucking dust from a metal & wood-grinding machine is the danger of inhaling sparks into a bag of super-flamable sawdust.The draft created by the dust collector can fan a little smoldering fire into a real inferno in seconds. Use only metal canister vacs (NOT Plastic or cloth bags!) and keep a really good fire extinguisher on the wall close by - and a working smoke detector is a MUST! :eek:
 
Bri in Chi said:
What you need to be very careful of, when sucking dust from a metal & wood-grinding machine is the danger of inhaling sparks into a bag of super-flamable sawdust.The draft created by the dust collector can fan a little smoldering fire into a real inferno in seconds. Use only metal canister vacs (NOT Plastic or cloth bags!) and keep a really good fire extinguisher on the wall close by - and a working smoke detector is a MUST! :eek:
Click to expand...

Great point! I can imagine what a spark would do to all that airborne fine sawdust. Would probably be like one of those grain silo explosions!

Norm
 
A possible solution is to use a metal can with water in the bottom as a "first stage" in your metal dust collector system.
 
A smoke detector would work great as long as you don't forge. When starting up a charcoal forge the entire shop will fill with smoke. Yes we have a back door open and both garage doors but that doesn't clear the smoke as fast as it is made.
 
i really like the cyclone idea, I was reading on another source about
a guy using a cyclone in an industrial process to pulverize material , I'm a
dormant home brewing hoping to become active again, I wonder If I could
design one that would serve as a dust collector and a grain " grinder".
yeah I know weird, but I got a small shop, things have to serve two purposes...... Hmm need to be carefully, the combination of exotic woods, good steel and beer could have adverse side effects......

I should have caught the angle thing on the dagger , it's kind of obvious isn't it " duuh" .......

It might be easier to put my belt grinder and table on casters and take it outside for grinding. I did figuare out that a respirator was necessary,
it didn't take long after the first session when I start coughing up nasty stuff to get it.....
 
Went to Container Store with SWMBO today, and noticed that they have cute little 6 Gal galvanized steel garbage cans w/ lids for $15. Perfect for making a first-stage for a metal dust collector. Or a fire-proof replacement for that crappy plastic trash can in your shop. :rolleyes:
 
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