What about rotary blades?

[YinTx]

So I have read some of the content in this section, and it has been useful.  But I do have one blade that I am vexed with.  How do I sharpen my rotary blades?  

I see rotary sharpeners, but seems like they make their own simple profile, and in many cases users complain the end result is worse than what they started with...

And what is a good material?  I see folks hawking everything from titanium to SKS-7 Tungsten Alloy, whatever that may be... 

Thanks, looking forward to hearing the thoughts of everyone on this....

YinTx

[Art]

Well, we cheat a little.  We've made up several mandrels to hold the blade, quite similar to ones for small buffs.  Blade in mandrel, mandrel in lathe (you could use a drill or a drill press) and apply the stones to the spinning blade.  Careful, these blades are seldom balanced and if you spin them up too far and too fast, they will come apart.  Can you say shrapnel? Again, a sharpie marked edge will indicate when you need to stop.

Art

[RockyAussie]

Now if we can just put the die grinder or dremmel into the tool post of the lathe.....

[electrathon]

6 hours ago, RockyAussie said:

Now if we can just put the die grinder or dremmel into the tool post of the lathe.....

Actually that is pretty easy to do.  As a hack way you weld a 2" long piece of a pipe split lengthwise to the tool lost.  Two hose clamps holds the grinder on to the "cradle". 

[Matt S]

Don't know about sharpening, but when I feel my rotary knife has lost its edge I loosen the friction screw and whack it on the polisher. If I get the right angle and pressure, it rotates the blade slowly as it polishes the edge.

[Dwight]

13 minutes ago, Matt S said:

Don't know about sharpening, but when I feel my rotary knife has lost its edge I loosen the friction screw and whack it on the polisher. If I get the right angle and pressure, it rotates the blade slowly as it polishes the edge.

Thanks, Matt, . . . I just changed mine yesterday, . . . started to toss the old blade, . . . decided to keep it, . . . gonna "practice" on getting it sharp.

Now I know how to do it, . . . I'm usually sharp enough to think of something like that, . . . but this getting old stuff sometimes don't let one think 100%.

May God bless,

Dwight

[YinTx]

A lot of quick responses, many thanks.  Unfortunately, I don't have a lathe set up, and the thought of a razor spinning at any rate of speed kinda worries me, so I might forgo that technique.  I will try the loosened blade method if my holder will do it, sounds viable....

 

Any thoughts on the best metallurgy for new blades?

YinTx

[Art]

2 hours ago, YinTx said:

A lot of quick responses, many thanks.  Unfortunately, I don't have a lathe set up, and the thought of a razor spinning at any rate of speed kinda worries me, so I might forgo that technique.  I will try the loosened blade method if my holder will do it, sounds viable....

 

Any thoughts on the best metallurgy for new blades?

YinTx

If your going to use power tools, and even some non-power tools, you are going have to get used to being around power cutting equipment, and grinding equipment, and stitching equipment, etc.

Fore blade metallurgy, I would go with some bi-metal format.  Soft stainless or carbon steel for the body and a hardenable long lasting stainless or high tech steel for the edge.  But you can't make the blades too good or you won't sell that many of them.

Art

[YinTx]

I am fairly accustomed to power equipment, having used it since I was 12 years old.  However, I am not accustomed to spinning things up like razor blades that were not intended to be spun up.  I have an aversion to that sort of thing, just me.

When you look to purchase rotary blades, they tend to be pretty general in descriptions of their metallurgy:  titanium, sks-7 alloy, high carbon, etc.  Even saying SKS-7 isn't specific it would seem, as there are a range of heat treatments that result in everything from a tool steel for dies, to railroad spikes, bolts, industrial boiler tubes, etc.  

Which leaves the end buyer, me, a bit confused when it comes to the plethora of choices available and the not always specific marketing associated with them.  The same is probably true of most knives/blades, hence the never ending disagreements around which material is best for what.

I guess if I am cutting 10 oz leather with a rotary blade, I'd need something different than if I am cutting silk.  

Anyhow, ramble off.  for now.

YinTx 

[YinTx]

Ran it across the strop tonight, night and day difference!  Thanks for the pointer, Matt!

YinTx

[WoodysWorkshop]

Trick is not let it get too dull and just strop it like your knife.

Wife freaked out when she cut pizza last week. I was touching up the kitchen knives and seen it in the drawer and it looked all dinged up.

She put pressure on it like it was 1/16" thick blunt edge. Made a good scar in the aluminum pizza pan, LOL.

I'm just glad she didn't have a finger in the way...

Took some lengthy work on the wet stones first and lots of stropping. But it took hair off the back of my arm slicker than greased lightning.

[xStarkweather]

I sharpen anywhere from 300-500 rotary blades a week. Get it spinning and put a stone to it would be the basic premise. That being said, you are going to want something to indicate it dead center on whatever you rigged up, and proper hones and stones. You can take it to a sharpening shop, probably cost you 5 dollars... Time is money.