DISC Grinders Who uses them??

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Diamond G Knives

Well-Known Member
Got a chance to use a Frink 9" vari speed disc grinder. Man Im impressed! I do mainly flat grinds, this is a great machine for me.

Ive got mine ordered, but just wanted to ask if anyone here uses them, and if they do, whats good or bad about them, also how do you have yours mounted?

What grits work best at what speeds?

Ill be posting some pics when mine gets here next week!!


God Bless
Mike
 
I have to and building one more. I use them mostly for grinding the tangs on fulltang knives. And i use them for grinding handle materials when i want them flat and square. I love them.2thumbs

Seved
 
Ive had intentions of building one capable of grinding a blade (reversable witha 1 degree bevel) on but havent done it yet. Right now I use a 6" one for flattening handles etc. works great

Sean
 
I use mine all the time. It is a home made one. I use a Beaumont Metals 9" beveled disc. The motor is a frequency drive 1125rpm with a VFD controller. It will go from 10rpm at nearly full torque (it pulses a little) to full speed both directions. Very handy. I couldn't get a dovetail to fit snug until I made my disc grinder.
 
>I am referring to these<


Imagine the vertical disc going in a circle. If you work on one side of the disc, it is going down. (the other side is going up). Of you are grinding a blade on one side, no problem. Nice even pressure on the blade. If your blade goes past the center, the side going up now comes in play and the "pressure" to hold the blade steady suddenly doubles. This causes the blade to unexpectedly twist. Not good when you want a nice finish.

The beveled disc has a 1degree taper from center to edge. When using this disc if the blade goes past center it has a 2degree gap (1degree taper on "each side" adds up to 2degrees) and the blade never touches the other side. The result is nice even pressure even if you go past the center.

What many people picture is the disc is highly beveled. It isn't. 1degree is almost invisible. I have to check them very closely side by side and then I mark them. The other thing to get your head around is gluing the abrasive to the disc. The image you get is the paper puckers and has wrinkles as it conforms to the concave surface. It doesn't. The 1degree taper is invisible to the abrasive disc. It bonds just fine with no puckers or wrinkles.

Finally, some ask about the concave surface creating a hollow grind and it is not dead flat. That is true. It creates a hollow that has a .0005" hollow over a 2" blade. It's just not a factor. You can't hand grind to with in .001" much less a .0005" tolerance.

Making a disc grinder is very easy. I'd HIGHLY recommend one.

Here is mine:
disc-grinder.jpg


I made the adjustable tool arm. If you look close you will see I have made the tool table reversible. The angled top you see in there is for making dovetails. I flip the tool rest over for a flat table.

It is a 3/4hp 1150RPM 3phase frequency motor. It uses a Teco 100 VFD that converts 220v single phase to 3phase to run the motor. VFD's are rated by horsepower. Rule of thumb is to use a VFD twice as large as the HP motor you are running. It's not required but you will shorten the life of you VFD if you don't.
 
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My 9" disc sander is probably the most used tool in my shop. I do mostly hollow ground knives but I use the disc sander on many parts. Variable speed really helps.
 
Everything gets flattened a little on the disc grinder. Everytime you grind, drill, or tap titanium, it gets burr so I hit them on the disc a lot.
 
BossDog said:
I use mine all the time. It is a home made one. I use a Beaumont Metals 9" beveled disc. The motor is a frequency drive 1125rpm with a VFD controller. It will go from 10rpm at nearly full torque (it pulses a little) to full speed both directions. Very handy. I couldn't get a dovetail to fit snug until I made my disc grinder.
Click to expand...

Same here. I built mine from a bunch of stuff laying around the shop, a treadmill motor and a controller I found on eBay.

ShopDisk1.jpg


The table tilts for dovetails, and I made an angle just for the way I like to do mine.

ShopDisk2.jpg


This angle is about 35 degrees.

ShopDisk04.jpg


I use this thing all the time. I am always looking for a better paper solution though and welcome suggestions. Paper doesn't last long.
 
Ive been working on this for about a year now and I finally got it finished. The disc sander stands are my own design. Disc #1 is a Baldor 3/4 horse motor with 1/4" mild steel frame painted copper colored and a steel disc. Disc #2 is 1/4 Stainless steel frame with a 3/4 horse Baldor stainless steel washdown motor and a steel disc. Disc #3 is 3/8" mild steel frame painted silver with a 3/4 horse washdown motor with an aluminum disc.

The control enclosure is a nema 4 with a speed pot and forward/reverse toggle switch and pilot light for disc #1. Disc #2 and #3 have the digop in the door and include a speed pot and RPM readout. The small magnetic tags and the numbers written on them are the grit of sandpaper that is on the sander. I plan on making better looking ones eventually.

The whole unit powers up with an Allen Bradley disconnect. The inside has a cooling fan and eventually will have an emergency stop as soon as I get the correct size contactor. The amp draw with all 3 sanders running at once is about 7 amps and it is on a dedicated 220 circuit with a 20 amp breaker. (no, I wont be running all 3 at the same time)



sand 2.jpg

sand 3.jpg

sand 4.jpg

sand 5.jpg
 
Michael...all I kept thinking while I was looking at this is NASA...I think the engraved placards are the coolest part...
 
very nice set up very well laid out. I love the controllers and enclosure. This is really how things should be done. I hope some of the other guys take notes for safety sake.
 
Man! Nice equipment!!!
Thanks for posting the pictures!

Just got in from the shop, had 4 forgings that got profiled and ground, all to 220, will HT tomorrow (made a new limiter plate today also)

It is simply amazing how well the disc is working for me! I profile, and knock the scale off on a 36 grit belt, then go to the disc with a 50 grit and set my blade bevels, then up thru 220 grit. All the blades are dead flat, and with the vari speed, it is such a joy to use this machine!!! I can already see my hand sanding will be cut WAY down!!!

Can you tell Im digging the new grinder?????:D

God Bless
Mike
 
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