New guard slotting machine

[kuraki]

...I'm sure I'm just being cranky now.

 

[Karl B. Andersen]

That is very much the smart and easy way of doing it.
Just after doing enough obscure parts you'll figure out all sorts of creative setups.

Please show me some pictures of doing it this way and how the guard fits up.
I've been milling my guard slots since the last century and never even considered the way you describe as the "smart and easy way".
Convince me.

 

[Karl B. Andersen]

That looks great Karl.

How did you get 90* corners for that slot on the guard without a file?

Uummmmmm inside the guard slot are 1/8" radius corners. You can see that in the top of the slot by looking in just a bit.
It was slotted with an 1/8" end mill.
I just did a small radius on the top and bottom edges to match the radius of the guard shoulder.
I can get another picture in the morning of the back side of the slot and you'll see the 1/8" corner radii in all four corners.

this is an edit - I just checked that photo again - if you look all the way through to the far side you can see the 1/8" radius as it travels through the slot.

 

[Karl B. Andersen]

I just snagged this pictured off of Photobucket, so it's older knife, but keeps me from taking new ones.
It shows a guard for a Bowie
Slotted with an 1/8" end mill still in the vise. Four 1/8" radius corners.



First slide down the tang to check fit. Notice radius on tang shoulders.






Now, notice where I radiused the bottom of the slot to match the guard shoulders on the knife but the top of the slot is still as-milled with 1/8" radius.
I do no filing INSIDE the guard slot.


If you look closely at the back of the guard slot - they are still 1/8" raidus


I may slightly round-over the tang corners to MATCH the 1/8" radius:



tap it on:

 

[Karl B. Andersen]

Watch this video from about 7:30 minutes forward to about 17 minutes and you'll see everything I mentioned above.
Keep in mind this was in deeply etched Damascus, so there is that variable as well.

 

[Matthew Gregory]

For the most part, I do it the way you do, Karl.

I have to admit, Geoff - I'm not sure I follow what you're saying. I'd love to see some shots or even a video of what you're talking about.

 

[Matthew Gregory]

By 'last century' you mean the nineteenth century, right Karl?

I've been milling my guard slots since the last century

 

[Karl B. Andersen]

By 'last century' you mean the nineteenth century, right Karl?

One in every crowd.............

 

[Geoff Flato]

I think we are miss understanding eachother, I'm saying your way is the smart and easy way.
You had asked how you'd get a square corner using a mill in an earlier post, and I was describing a setup for that.
I do it the way you described the majority of the time. I'll only use the alternative method I described when required, as it's a lot more setup time.

For everyone interested, I'll set up and mill the shoulders on a blade the way I described tomorrow, and take some pictures of the whole process.

 

[Karl B. Andersen]

For everyone interested, I'll set up and mill the shoulders on a blade the way I described tomorrow, and take some pictures of the whole process.

I look forward to seeing it. And thank you.
One of things I constantly notice on this forum is a whole lot of talk, and not a lot of photos showing it.

 

[Geoff Flato]

I look forward to seeing it. And thank you.
One of things I constantly notice on this forum is a whole lot of talk, and not a lot of photos showing it.

That is definitely a common occurance on forums in general...
Unless you can prove what you're talking about, trying to sound smart is often a good way to look stupid.

 

[butcher_block]

i work much thinner stock .113 mostly so i end up using a file guide and totaly rounding the tang to fit a 3/32 cutter slot

 

[Geoff Flato]

So here it is. Starting with a Loveless style fighter blank which will have a hidden tang.

This is the sort of endmill I'd usually use, a radius corner. This one is quite dull though and the new ones haven't arrived yet, so I'll use a kenemetal indexable endmill for demonstration purposes. It has a 1/16" radius which would probably be sufficient, buy I'll recut it later regardless.

Well start by positioning the blade in the mill vise for the first cuts. Location in the vise is rather critical to allow access and still be rigid enough to prevent chatter on one specific cut. I use a couple parallels to eyeball it as level as possible, but you could do that any number of ways. This first stage isn't critical as long as it's fairly close. We are going to establish reference surfaces to work off. The lead hammer on the mill table is used to adjust and seat parts in the vise.

The first cut is to establish the primary reference surface. If the design allows, the spine of the blade is an ideal surface as it allows you to simply sit it on a parallel in the vise to insure the shoulders are perfectly square with eachother. If this isnt possible you can mill the top edge of the tang, and dial it in with a test indicator or surface gauge when you flip it. This is obviously much more of a tedious pain, and should be avoided if possible.

The next step is to cut the secondary reference. The primary reference determines squareness of the shoulders, and the secondary reference establishes the position of the shoulders relative to eachother. This is done by simply milling the end of the tang flat and square.

Now it's time to actually mill the first shoulder. Cut it until it's cleaned up, and then without moving anything, lock the X axis of your table in place.

Now comes the critical part to insure everything fits properly. Currently you have a shoulder cut, and the endmill fixed on a specific position along the X axis of your bill table. If you flip the blade over we already have a reference surface on the spine to insure squareness. This leaves positioning the blade in the exact same place along the X axis. So before loosening the vise, zero a dial indicator against the secondary reference surface cut on the end of the tang.

Now you can take the blade out of the vise, and flip it over to spine side down. Use the previously mentioned lead hammer to insure its seated against the parallel, and your shoulders will be perfectly square to eachother. Sit the blade in the vise as to rezero the dial indicator, and your second shoulder will be within tenths of the first one.

Now simply turn on the mill, adjust the knee to the required height to clean up the full shoulder, and take one cut with everything as it sits. Both shoulders will be perfectly square to eachother, and in (as far as knifemaking is concerned) perfect line with eachother.
It looks like a real slow process, but even with stopping to take pictures it was less than 5 minutes from start to finish.
I wouldn't do it this way for every knife, but it's a useful setup to know at times.

Hopefully someone will find this useful

 

[Matthew Gregory]

Geoff, I promise I'mnot asking this to be a jerk.

The jerk part just comes naturally for me.

Is there any way you can show a shot of what the results of that cut look like, or did you not do it for this photo shoot. Totally understand if you didn't. You demonstrated what you were talking about, and that's enough, I'm just curious.

 

[Geoff Flato]

I didn't take it quite far enough on the right side to clean up, but I was just trying to do the minimum to demonstrate the process as I will be recutting it with a larger radius. I guess I just figured everyone had seen a tang with square shoulders before, so I didn't bother taking that picture.
But here it is

Checking with a diemakers square shows both shoulders are perfectly square to the tang and match eachother perfectly. It looks a little off in that picture for some reason

 

[john april]

there may have been a miscommunication in terms, in post #28 karl asked about the guard shoulders and in post #29 geoff explained about the blade shoulders. what do you guys consider the minimum safe radius for shoulders on the blade? mine look bigger than most, i wonder if i am making too much guard work for myself by having to file those curves on each end of the slot.

 

[Karl B. Andersen]

i work much thinner stock .113 mostly so i end up using a file guide and totaly rounding the tang to fit a 3/32 cutter slot

Excellent idea! It works.

 

[Geoff Flato]

That must be what happened, it seemed like we weren't having the same conversation.

I usually go for about a 1/8" radius. More wouldn't hurt anything, but its always a trade-off.
I wouldn't assemble a knife with the shoulders I posted. That was done with what I had on hand until the KBC order arrives. I will recut those to a larger radius before going any further

 

[Karl B. Andersen]

It looks a little off in that picture for some reason

They don't look off to me. Thanks for posting those pictures.

 

[Karl B. Andersen]

what do you guys consider the minimum safe radius for shoulders on the blade?

I don't really know for a fact what the minimum would be.
My radius matches a 1/8" end mill.
I would say that as large as you can go and still make you components fir precisely, then go for it.