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jheinen

Power Hammer or Mill?

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This last weekend I attended the Northwest Blacksmith Association Conference (an awesome event, BTW!), with the intent of bidding on a newly constructed tire hammer that was in the auction. Unfortunately, and as I expected, I was outbid. The hammer went for $3,750, and I was only prepared to go up to $3,000. Sad, I know. :(  While at the conference I also had a chance to meet with one of my mentors, David Lisch, to get a critique on my latest work. He pointed out the numerous flaws that I had overlooked and, as always, gave invaluable advice (for new knife makers, I can't stress enough how valuable seeking out those with experience can be. You can learn more in 20 minutes from a master than you can learn in two years of trial and error). 

The upshot of all of this is that David talked about the utility of a milling machine, especially for things like facing ricassos and slotting guards. To date, I've been doing the normal drill/file routine, and it's a continual challenge to get that PERFECT fit. Regular folks might look at my knives and say "wow, that's incredible!" But another knife maker can spot those small details that don't quite work. So my question for the collective wisdom of this group is; would I be wiser investing in a small milling machine at this stage, or would a power hammer be better? I have used several power hammers, and I like the ability to move steel, especially for damascus. On the other hand, since my goal at the moment is to focus on the ABS journeyman test (damascus not allowed), I am beginning to think that I would be better served by a mill. The added bonus is that a mill would be cheaper, and opens up a whole new universe with respect to making other tools (more file guides!)

What do y'all think?

To give you a sense of where I'm at in my abilities, Here's one of my first knives from a couple of years ago:

fullsizeoutput_1052.jpeg

And here's one of my most recent knives:

435680781_czD8oop5SGCR97Iuerkg.jpg

 

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I think you and Dave answered your question already.  A mill would help you get a lot closer to getting your JS than a hammer would.  What kind of mill were you thinking?  

And if you don't mind my asking, what flaws did Dave gig on you on?  I have been meaning to take a knife down to him and have him check it out.  Also, my buddy Dave Tuthill was there this weekend, so you may have met him.  He may have had his dog Odin with him, who looks kinda like a wolf.

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I'm looking at either the Grizzly G0759 (which is basically the G0704 w/DRO), or the Little Machine Shop High-Torque Mini Mill Deluxe. I think I'm leaning toward the Little Machine Shop mill as from what I've read it has better quality control, and a belt drive. 

I did see David T. at the conference, though I didn't see Odin. Didn't get a lot of time to chat, but I'll be at his axe class in a couple of months.

As for the problems with my knife, the main thing he noticed was the fit of the guard. There was some slight gapping at one corner where the ricasso meets the guard, and the guard was a little loose. I hadn't glued the knife up yet, so it was basically a take down. With the butt cap not tightened down, the guard could wiggle a little. The guard was also very slightly out of square with the ricasso.  All of those issues are things I could resolve with a mill. I tried a heritage/museum fit on the handle, and I left the handle a little too proud of the guard. He also suggested I chamfer only the handle, while leaving the guard and butt cap edges square. Interestingly, Kevin Cashen suggested I chamfer both. David also didn't like my handle construction (the way it's taught at the ABS Handles & Guards class). I brazed a connector nut on the inside of the butt cap, which is screwed on to the threaded tang. David thought it would allow for too much movement of the wood, which might cause gapping down the road. It was great feedback, and he gave me a couple tips to help with the problem areas (e.g. putting a couple of wraps of gorilla tape around the guard and grinding the handle flush with the tape will give you just the right dimension on the handle for a heritage fit).

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Have you checked out Precision Matthews?  I have never used one, but I know a few guys with them, and they love them.  I will be buying  a PM-25 with DRO at some point in the future.  Hopefully (maybe) some time this year.  We shall see.

As for the comments, it sounds like a lot of the gaffs would have been avoided with a final fit up.  It also sounds like a lot of it comes down to personal preference as well.  

How do you currently fit up your guard?  I will flatten my ricasso on my disk grinder, and use some digital calipers to make measurements so I know I am square.  Once I am square, I then will use my file guides to do my shoulders.  I also make sure my guard stock is square by using my disk grinder with a table and engineers square.  It works out pretty well.

Are you using stabilized woods?

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Okay, I think I'm leaning toward that PM-25! Very nice machine. Unfortunately they are currently out of stock. :(

For my guard fit up, I profile and grind the blade to 120 grit, including the shoulders. I flatten and true things up on the disc grinder. After getting things fit I do the final hand polishing to 600 grit. Both you and Dave seem to cut the shoulders later in the process, so I think I will give that a try. Dave said he pretty much gets the blade fully finished and polished to 600 grit before cutting the shoulders. I don't have a table for my disc grinder, and I expect that would help a lot, although a milling machine probably makes that moot as I expect I could mill everything to within a couple thousandths (you can use a mill to flatten the ricasso, right? I don't have a surface grinder).

I usually use natural wood, though sometimes I'll used stabilized (the knife in the picture on this thread has a stabilized handle).

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2 hours ago, Jonathan Silas said:

 Ok that looks like entirely to good a deal, what's the catch? 

They're from Taiwan.  Still good tools, equal to and sometimes better than Jet, and worlds better than Grizzly.  But still able to keep the price low.

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1 hour ago, Alan Longmire said:

They're from Taiwan.  Still good tools, equal to and sometimes better than Jet, and worlds better than Grizzly.  But still able to keep the price low.

Well the only Grizzly product I have ever used was their version of a "Gunsmith" lathe, it cut pretty well with minimal chatter. So if this is better than that it should be great for small stuff. So It's not just an up sized drill then that's going to blow out when lateral stress is applied? 

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No, they are real milling machines.  Just don't overload 'em and you'l be fine.

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As a machinist, i tend to lean towards the mill. Power hammers are one trick ponies; they hammer. Thats good for a handful of things, but with a mill, there is so much potential for fabrication. If you have a lathe, a mill, a welder, and a touch of know-how, i swear there is nothing you cannot make. 

It also seems more pragmatic, given your situation. 

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You can also get a decent mill off Craigslist for $1500, depending on your location. Heck, I got my South Bend mill (about the size of a Bridgeport) for $600 and the ways still have their frosting on them. It's all about knowing what to look for...

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Craigslist - helping murder people since 1995!  LOL.

Seriously, I wish I had the space for a Bridgeport.

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I have a milling machine and love it. I guess you know that there is a lot of stuff you need to get in addition to the machine. Some things you may need to get include:

3 jaw chuck (Jacobs chuck), collets, machine vise, hold down clamps, caliper and or micrometer, end mills. These can add to your cost. 

Edited by Bill Kirkley

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I was taught to use a mill to slot my guards and I bought the Sherline Mini mill specifically for that purpose. For a few years I used it for every guard, but lately I have been doing them by hand and I found it's faster and I can get the same tight fit. I still use the mill for surfacing some stuff, but it's not necessary by any means. 

On ‎5‎/‎14‎/‎2018 at 4:09 PM, jheinen said:

Both you and Dave seem to cut the shoulders later in the process, so I think I will give that a try. Dave said he pretty much gets the blade fully finished and polished to 600 grit before cutting the shoulders.

I cut the shoulders early in the process (after 220 on the disc) and finish the blade and ricasso area to 400 grit before fitting the guard. If you cut shoulders all the way around the tang, you will have less problems with gaps in the fit. If you set the guard so that the blade shoulders inset into the guard a little bit, you will have zero gaps. Then you can surface the guard face down to the bottom of the inset for the ultimate clean fit.

 

On ‎5‎/‎14‎/‎2018 at 4:09 PM, jheinen said:

(you can use a mill to flatten the ricasso, right? I don't have a surface grinder)

Yes you can, but that requires some pretty expensive mill bits to surface hardened & tempered steel. You do not need a surface grinder either, although it does make it easier and faster. I do the bulk of my flattening on the 2x72 and follow up with the surface grinder, but before I had the surface grinder, I used the disc to finish the ricasso to 400 grit (I still do BTW). Getting the ricasso sides perfectly parallel is not mandatory and even 10-20 thousandths out won't matter if the blade edge is centered anyway. A lot of my ricassos aren't parallel sided and will taper from top to a thinner bottom. I like the look and it makes the plunge cuts shallower and easier to finish.....;) It does make the slotting of the guard a little tricksy, but it's good practice for those blades with no ricasso. 

On ‎5‎/‎14‎/‎2018 at 12:13 PM, jheinen said:

The guard was also very slightly out of square with the ricasso. 

How so? Was the guard not square to the center line of the blade, or was it not square to the spine?

Edited by Joshua States

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On 5/14/2018 at 4:09 PM, jheinen said:

Okay, I think I'm leaning toward that PM-25! Very nice machine. Unfortunately they are currently out of stock. :(

For my guard fit up, I profile and grind the blade to 120 grit, including the shoulders. I flatten and true things up on the disc grinder. After getting things fit I do the final hand polishing to 600 grit. Both you and Dave seem to cut the shoulders later in the process, so I think I will give that a try. Dave said he pretty much gets the blade fully finished and polished to 600 grit before cutting the shoulders. I don't have a table for my disc grinder, and I expect that would help a lot, although a milling machine probably makes that moot as I expect I could mill everything to within a couple thousandths (you can use a mill to flatten the ricasso, right? I don't have a surface grinder).

I usually use natural wood, though sometimes I'll used stabilized (the knife in the picture on this thread has a stabilized handle).

I actually cut my shoulders just before I heat treat.  The blade geometry is done, and ground, and the last step before heat treating is to cut the shoulders.  I do not fit guards until post heat treat, when I have sanded the blade out to at least 600 grit, so I am past the point where I am doing big material removal.  There are many times though were I will recut the shoulders if I am unhappy with them.  This is only done though when the blade is differentially heat treated, so the area of the shoulders is still soft enough to file.  

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On 5/16/2018 at 6:05 AM, Bill Kirkley said:

I have a milling machine and love it. I guess you know that there is a lot of stuff you need to get in addition to the machine. Some things you may need to get include:

3 jaw chuck, collets, machine vise, hold down clamps, caliper and or micrometer, end mills. These can add to your cost. 

What do you use a 3-jaw chuck for? I thought that was for lathes?

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14 hours ago, Joshua States said:

How so? Was the guard not square to the center line of the blade, or was it not square to the spine?

Not square to the spine. If you hold the knife with the blade pointing up and look where the spine meets the guard, the guard is tilted just a hair to the right.

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31 minutes ago, jheinen said:

Not square to the spine. If you hold the knife with the blade pointing up and look where the spine meets the guard, the guard is tilted just a hair to the right.

That's what I think of as "not square to the center line of the blade".  Do you check the alignment with a mirror? 

I can explain better with a few pictures.
In the first pic you will see the guard material slotted and press-fit to the blade, tight against the shoulders.
Attached Image

Then you hold the mirror flat against the guard above the spine.
Attached Image

Now look straight down the blade into the mirror. If the guard is square to the center line of the blade, it will appear in the mirror in a straight line with the blade. If it isn't square, it will appear "bent" to one side or another. Like this.
Attached Image

This guard needs to come forward on the right side of the blade (on the left in the photo). So I will chuck it back up in my guard setting jig and push the guard in the direction desired.

Once I have adjusted it a little, I recheck for square using the mirror. When it is perfectly square, it will appear in a straight line in the reflection.
Attached Image 

Edited by Joshua States

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Yes, this is exactly the problem on the blade in question. I like the mirror trick.

Edited by jheinen

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As a retired machinist I would say go fer the mill you will need it to build a power hammer,

and as Will also said, with a lathe, mill, and a welder you can make most anything you want......B)

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Jheinen

You are right, I meant a Jacobs chuck, which I guess is a three jaw chuck :-)

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