The difference a disk makes

Crag the Brewer said:
-Not sure? Ive seen blades that look like their plunge was made with a disk grinder.
But, I bet that was done pre hardening...... Cause it's pretty slow to remove metal after hardening on a disk.
Click to expand...
That s what you think ........ :) Disk can remove steel almost as fast as grinder , depends on grit size , speed and pressure .
About plunge , I make dedicated disk sander just for that

Curved plunge

How you would grind this ? Disk sander have big curve for that ?
www.bladeforums.com www.bladeforums.com
 
Natlek said:
That s what you think ........ :) Disk can remove steel almost as fast as grinder , depends on grit size , speed and pressure .
About plunge , I make dedicated disk sander just for that

Curved plunge

How you would grind this ? Disk sander have big curve for that ?
www.bladeforums.com www.bladeforums.com
Click to expand...
I think I would be worried about ruining the heat treatment....
Maybe I am shy with the pressure I apply?
 
This Brodbeck attachment is the absolute cheapest way to have a variable speed disc sander which also tilts. Only thing is you need a 2x72 and a vfd. Downside of this system is primarily the incompatibility with a work rest, although I'm sure something could be rigged up
 
Lorien said:
This Brodbeck attachment is the absolute cheapest way to have a variable speed disc sander which also tilts. Only thing is you need a 2x72 and a vfd. Downside of this system is primarily the incompatibility with a work rest, although I'm sure something could be rigged up
Click to expand...
I have the same grinder setup and I love it! I do find that the disc tends to sit a bit higher than I would prefer when it's setup like you showed, so I usually mount my disc attachment in the lower attachment location (the one where you put your work rest).
 
Michael Black said:
I have the same grinder setup and I love it! I do find that the disc tends to sit a bit higher than I would prefer when it's setup like you showed, so I usually mount my disc attachment in the lower attachment location (the one where you put your work rest).
Click to expand...
Good to see the good feedback on this system. I'd really been looking at this given the lower cost and versatility.
 
the reverse switch I ordered for my vfd showed up today, pretty excited to get that going. This Brodbeck attachment is working pretty great so far- no regrets!
 
Here is my setup. I made a squaring jig out of a piece of aluminum square tubing that I squared the face/bottom on after I epoxied a piece of hdpe on it to help it slide. I mount the knife by putting one of the tang holes on one of the horizontal screws and then placing screws on the vertical line in the middle to where the blade can‘t move up and down much. The screws don’t stick out past the surface of the knife. Then I stick a couple of strong magnets inside the tube and that holds the knife solidly in place. I’ve also found that if I do a little bit at a time on each side I get better results. They seem to get flatter faster than when I do one side completely before I switch sides. Obviously make sure your work rest is square to the disk before starting. Seems simple but you’ll know quickly the first time you forget.
I use a carbide faced file guide to grind the main bevels but if you have a gently radiused plunge it WILL cut a line into it if you run up on it. On the blade/bevels I make sure to initiate contact with the disk with the tip ever so slightly pointed in with the edge rotated slightly toward the disc. This helps avoid rolling on the outside edge of the disk and cutting a groove. I generally only go up to P3205 then finish on my surface plate. Once the knife/face is flat it’s just faster for me this way because I can stick multiple grits on my stone at once and it generally only takes a few minutes for each grit. It also removes the risk of rolling on/off the edge of the disk and cutting a groove in the knife. I use the 3M Pro (purple stuff 80-120 grit) when I need to take off a lot material then switch to Rhynowet (red) for a better finish. Low speed seems to work best in my experience. I rarely go beyond 30% on the vfd. You can remove a ton of material quickly but even good paper doesn’t last long.
It’s great for cleaning up tangs too as long as they’re straight or have an outward radius.
IMG_9626.jpeg
 
Well, I finally finished my build 😊 thought I would share pics. Kbac24d VFD iron horse 1 hp motor, flat 9 disc by TruGrit and stand by usa knife maker. Very happy with the final result! Mounted all to a wood top cabinet for some storage. Peace ✌️

John
JV Knives

IMG_2240.jpegIMG_2239.jpegIMG_2230.jpegIMG_2231.jpeg
 

Attachments

  • IMG_2238.jpeg
    IMG_2238.jpeg
    48.7 KB · Views: 5
Michael Black said:
I have the same grinder setup and I love it! I do find that the disc tends to sit a bit higher than I would prefer when it's setup like you showed, so I usually mount my disc attachment in the lower attachment location (the one where you put your work rest).
Click to expand...
So I assume this Brodbeck attachment is compatible with other types of 2X72 grinders other than their own?
 
Lorien said:
This Brodbeck attachment is the absolute cheapest way to have a variable speed disc sander which also tilts. Only thing is you need a 2x72 and a vfd. Downside of this system is primarily the incompatibility with a work rest, although I'm sure something could be rigged up
Click to expand...
I found a Canadian distributer and ordered one with the arm. My 2X72 has a KBAC-27D with reverse. I was reading the instructions on their website, and see that it is required to adjust the trimpots...but doesn't say why. Anyone know? Thanx.
 
I'd be lost without my disc grinder. I've been using one for 25 years now but only had variable speed for about 10 years. It was huge difference maker for me. I rough grind my bevels on the 2 x 72 up to 220 then I finish on the disc grinder with 1/8" cork backing up to 800+. It's makes cleaning up and evening out the plunges much easier for me than doing on the 2 x 72. I now spend minutes hand sanding blades instead of hours. I have the Nelson disc grinder system that I can change out the discs in seconds.
Jim
 
weo said:
I wonder why I didn't sooner.
Click to expand...

I know why. I have 5 of his discs plus the hub $$$$$$$.
Which cost a lot more then many guys disc grinder.


The abilty to rapidly change disc is worth every penny.

When you know, you know.

My TruGrit/Nielson disc grinder cost me more then my 2x72 did:p
 
AVigil said:
I know why. I have 5 of his discs plus the hub $$$$$$$.
Which cost a lot more then many guys disc grinder.


The abilty to rapidly change disc is worth every penny.

When you know, you know.

My TruGrit/Nielson disc grinder cost me more then my 2x72 did:p
Click to expand...

Can someone explain why This is a good thing?
I Love tools. I buy things I don't need from time to time.....
But this doesn't make sense to me?

Why do I want to change the disks???
They (the sanding sheets) dull so quickly.

Why not just stick, & cut a NEW grit on your disk?



Are you people grinding soft bevels, and grinds?

All my blanks are ground Hard, maybe that's the difference?

I go through multiple sanding sheets of the Same grit.
No need to swap.

Edit: also I use feathering adhesive. I Could swap/replace sheets with my plain disk.
They pull off easy, and I could replace if I wanted to....... But they just don't last long enough to bother.
 
Last edited:
Crag the Brewer said:
Can someone explain why This is a good thing?
I Love tools. I buy things I don't need from time to time.....
But this doesn't make sense to me?

Why do I want to change the disks???
They dull so quickly.

Why not just stick, & cut a NEW grit on your disk?



Are you people grinding soft bevels, and grinds?

All my blanks are ground Hard, maybe that's the difference?

I go through multiple disks of the Same grit.
No need to swap.

Edit: also I use feathering adhesive. I Could swap/replace disks with my plain disk.
They pull off easy, and I could replace if I wanted to....... But they just don't last long enough to bother.
Click to expand...
I agree with you... I go through sandpaper on my disc's so fast it doesn't make sense to swap disc at all
 
REK Knives said:
I go through sandpaper on my disc's so fast it doesn't make sense to swap disc at all
Click to expand...
If you wear out your sandpaper with each use, you are right it would not make sense.

But in a morning I might have the need for a minute with 60 grit, then need to use 100 grit for a few seconds followed by 220, 400 for short period of time and finished off at 600 rubber backed disc. Never completely wearing out the abrasive disc in one use.

I can pop a disc on and go to another grit quickly without having to remove the paper each time and deal with the adhesive and storing the paper for use again.

I use feathered adhesive for a long time and removing a brand new piece of abrasive to install another grit, having to deal with all the partially used abrasive discs becomes ridiculous.

Being able to change grits on your 2x72 quickly is just as important for your disc as well in my opinion.
 
You must log in or register to reply here.
Back
Top