Machined steel rectangle?

A

Alex Baliles

Joined
Jan 1, 2026
Messages
23
Ive been going back to old videos and WIPs and see people using machined steel rectangles with radius edges to dial in plunge lines and so forth. All i can seem to locate are Jewlers blocks and most have 90 degree edges. Anyone have an idea where I can source something like Nick Wheeler used in his Bowie videos?
 
Edit: I think I misunderstood the question.

What you are looking for are usually called a waterfall platen. If you search waterfall platen online you will find lots of options. Some are a hardened platen with a radius-ed bottom edge and some have a small contact wheel. Nathan (The Machinist) Carother may have popularized this technique. He sold a batches of the former type on BladeForums years ago. Without the contact wheel, these platens will quickly get hot, so they are often paired with a platen chiller.

Nathan the Machinist

Thread 'Hardened flat platens, radius platens, water cooled platen chillers.'

36", 48", 72" curved platens, flat platens and water cooled aluminum chillers. The end of the flat platens have an accurately machined radius that can be used for lengthwise grinding and finishing plunges. There are now two styles of the flat platen available. The original style with 1/8" radius on one end and 1/4" radius on the other, and a new large radius option with 3/8" and 1/2" end radius.

You don't have to use the end radius to make use of these flat platens. The original idea was just a hardened flat platen. While it was on the CNC I cut an end radius, it's no big deal. Some folks...
 
Last edited:
Interesting! Personally to cut radiused plunges I like to use a 120 grit j-flex belt and adjust the tracking so that it hangs over the edge of the wheel/platen, an old Loveless trick. :)
 
Rolling j flex belts over the side of a flat platen or waterfall platen is the way most people do it. I generally use my carbide faced file guide to scribe two sets of parallel lines on each side of the blank when I’m cleaning up plunges. One is to take the plunge line to and the one behind it ensures I’m lined up evenly from side to side if I grind to the point I can’t quite see the first line.

If I remember correctly Wheeler described how he made his block in one of his videos. I believe he just got a block and scraped the edges with a radius gauge of whatever size he wanted. It doesn’t take much of a radius when you factor in the thickness of the sand paper.
 
ScarFoot said:
Rolling j flex belts over the side of a flat platen or waterfall platen is the way most people do it. I generally use my carbide faced file guide to scribe two sets of parallel lines on each side of the blank when I’m cleaning up plunges. One is to take the plunge line to and the one behind it ensures I’m lined up evenly from side to side if I grind to the point I can’t quite see the first line.

If I remember correctly Wheeler described how he made his block in one of his videos. I believe he just got a block and scraped the edges with a radius gauge of whatever size he wanted. It doesn’t take much of a radius when you factor in the thickness of the sand paper.
Click to expand...

That makes me think... I just got a carbide platen from Contender, I'd like to radius the edges but I'm not sure whether a diamond file will be up to the task...
 
DeadPineKnives said:
That makes me think... I just got a carbide platen from Contender, I'd like to radius the edges but I'm not sure whether a diamond file will be up to the task...
Click to expand...
Diamond files make short work of carbide. That’s what I use on mine. You can grind them with ceramic belts but it’s time consuming and potentially less precise than hand filing them.
 
SirSpice said:
Edit: I think I misunderstood the question.

What you are looking for are usually called a waterfall platen. If you search waterfall platen online you will find lots of options. Some are a hardened platen with a radius-ed bottom edge and some have a small contact wheel. Nathan (The Machinist) Carother may have popularized this technique. He sold a batches of the former type on BladeForums years ago. Without the contact wheel, these platens will quickly get hot, so they are often paired with a platen chiller.

Nathan the Machinist

Thread 'Hardened flat platens, radius platens, water cooled platen chillers.'

36", 48", 72" curved platens, flat platens and water cooled aluminum chillers. The end of the flat platens have an accurately machined radius that can be used for lengthwise grinding and finishing plunges. There are now two styles of the flat platen available. The original style with 1/8" radius on one end and 1/4" radius on the other, and a new large radius option with 3/8" and 1/2" end radius.

You don't have to use the end radius to make use of these flat platens. The original idea was just a hardened flat platen. While it was on the CNC I cut an end radius, it's no big deal. Some folks...
Click to expand...

No sir. Its an actual block of steel or
Aluminum that he wraps a piece of sandpaper around.
 
If you mean a hand held sanding block, just sand the edges on a block of steel, aluminum, micarta as desired and use it. A good hard wood will also work.

EDM stones do a great job for cleaning up plunges.
 
Stacy E. Apelt - Bladesmith said:
If you mean a hand held sanding block, just sand the edges on a block of steel, aluminum, micarta as desired and use it. A good hard wood will also work.

EDM stones do a great job for cleaning up plunges.
Click to expand...
Of sorts. Yes. The one im after looks perfectly machined though. Im not sure I could get a nice radius or a nice finish on it myself like the one he used though.
 
You are probably overthinking this. Just get a piece of flat metal and round the edges to what looks good. Some makers use a small chainsaw file (1/8" to 3/16") to start the plunges, grind h bevels to them, and use a sanding block with the same radius on the edges to clean the grinds up.

The honest truth is I have never used any radiused edge sanding block. I just use flat and square pieces of aluminum/micarta, wood and sand carefully.
 
He literally describes how he made it in one of his videos. It’s been a few years since I watched it but I think it was a block of something like O1 that he surface ground flat and scraped a radius on the edges/corners with a cheap radius gauge. I don’t remember if he hardened it after that or not. If you don’t have access to a surface grinder, a piece of sandpaper on a surface plate and some elbow grease works just fine to flatten the block. If you don’t want to buy a radius gauge just drill an appropriate sized hole for the radius you want through a piece of metal and grind all but a quarter of the circumference of the hole away and harden it.
He just wrapped Duragold self adhesive sandpaper over the radiused edge and cleaned his plunges with it.

There’s a thousand different ways to clean up plunges. That’s the one he showed in his videos.
 
Alex Baliles said:
Of sorts. Yes. The one im after looks perfectly machined though. Im not sure I could get a nice radius or a nice finish on it myself like the one he used though.
Click to expand...
I made a really crude one last year and worked the same.
Here is an old picture I found on Instagram. Just a piece of mild steel (I didn't do anything to it) and I filled a quick radius that seemed good enough.
Screenshot_2026-01-16-23-27-38-727_com.instagram.android.jpg
While the block works, I'd advice getting a file guide and just filling the plunges in. File guide and filling is much faster and you can change the radius by simply changing the file.
 
Tony brings up an important thing - A File Guide.
Using one to file and grind shoulders at the tang and plunges will make a huge difference in your blades.
While you can make or buy a hardened steel file guide, a carbide file guide is what you want. There are several suppliers offering them.
 
Last edited:
Stacy E. Apelt - Bladesmith said:
Tony brings up an important thing - A File Guide.
Using one to file and grind shoulders at the tang and plunges will make a huge difference in your blades.
While you can make or buy a hardened steel file guide, a carbide file guide is what you want. There are several suppliers offering them.
Click to expand...
Yes sir. Just got one this week
 
Last edited by a moderator:
You must log in or register to reply here.
Back
Top