Disc Grinder Build / W.I.P.

[Melsdad]

I hope this fits in the W.I.P category since it is a knife making related machine. I wanted to add a disc grinder to my shop. I built my own belt grinder a few years ago and that was a fun project. A disc grinder looked a lot simpler so I started gathering parts. I looked at what was offered to buy as complete units and used bits and pieces of designs from different models. The Nielson disc system is an awesome idea so I incorporated that into my machine. I also used a few features of the Beaumont grinder as well. I worked on this project off and on for the last few months, but I documented the build along the way. So here goes! The material I used was 6061 Aluminum and 1018 cold roll.
Let’s start with the base. It is .500” thick aluminum.

Here are a few shots of squaring up the base plate.


Now the edges are square and the plate is sized. It is time to drill and tap some holes.


I didn’t take any pictures of the machining, but this is the riser block that the motor sits on.

Next will be the clamp arm posts that will hold the work rest. They are 2” square 1018 cold roll. I machined them in pairs so they are identical and everything will stay square.



I decided to surface grind the clamp arm posts. These will be black oxide coated.

 

[Melsdad]

Now let’s work on the arms for the work rest. The arms were also surface ground in pairs so they are identical. They are .010 smaller than the holes in the posts. I drilled and reamed a .500” hole in the ends of the arms for location on my rotary table to mill the radius on the clamping ends of the arms.

Here is a fixture plate that has the same .500” reamed hole. This will be clamped to the rotary table and the arms will be clamped to this for easy alignment with a dowel pin.



Radius finished, I just repeat the process for the second arm.Notice the small holes in the side of the arm. These are for the clamping screws once the arms are slit so it will grip the axle.


I will finish this up tomorrow.

 

[Melsdad]

Next I aligned both arms in the vise with the dowel pin in the holes. I drilled and bored the arms for a slip fit for the 1.00” dia. rod that will be the axle for the work rest table.


This is a cut off of the axle piece. Notice the small holes in the arms. These are for the clamping screws once the arms are slit so it will grip the axle.

Here are the slots cut in the arms. This was done on a wire E.D.M. machine. I didn't have a slitting saw the proper diameter to cut these slots.

The next two pictures....don't ask me how I posted them in this format.

Anyways..I wanted the clamp arm posts to be the same height so the work rest table would be square and not bind when installing or removing it. I used one of the clamp arms and tightened the posts to it and took a cut off of the bottom of the posts so they both matched perfectly.

 

[Melsdad]

This is the axle for the table to mount to. I'm milling a flat were the table will be bolted from the underside. I am also using dowel pins to keep the table parallel to the axle.

 

[Melsdad]

After the axle was finished I made the table. It is .750" thick aluminum. I will mill a slot in the table later for a bevel gauge to ride in. That was the main reason for doweling the table to the axle. So the slot will remain parallel with the face of the discs.

This is roughing in the pocket that the disc will run in. The two tabs on each side will be 2.00" behind the face of the disc.

finish pass. Those radius-ed corners will be squared up in the next operation

In order to be able to tilt the table to 45° I need to relieve the underside of the table so the top surface can get close to the disc. To do this the table was mounted to the tilt table at 45° and the relief was milled and the corners squared up.

Here you can see the tapped holes as well as the dowel pin holes for the axle


Here is the axle mounted to the table. Things should be starting to make sense now.

 

[Melsdad]

I didn't get any pictures of the turning work of the aluminum hub that the discs mount to but I did get a few of drilling and reaming the holes for the magnets.


The holes are complete and the magnets are pressed in.

 

[Melsdad]

I had a dozen .250" thick discs laser cut out of steel plate. The material was not flat so they needed to be surface ground before the I.D. and the O.D. were sized. Notice the shims under the discs. This was to get the first side flat.



Next was the lathe work. I bored the I.D. of the removable discs to +.002 oversize of the hub of the aluminum magnetic mounting plate
Then I turned up a mandrel to mount the discs to to turn the O.D. true to the I.D and cut the relief bevel on the back side of the discs.




Complete Flat disc. I made 4 that had a 1° face angle

 

[Melsdad]

The motor is a 2hp. 3 phase 1725 rpm. I use the same VFD as my belt grinder. I just plug the machine I want to use into the VFD and make sparks.

Here are a few shots of things all put together.

 

[TacticallySharp]

Nice! Thank you for sharing.

 

[KenH]

VERY nice build - Now I see another reason I "need" a rotary table! That sure puts a nice radius on the ends. I like where you put the slits in the arm for the pinch bolt to hold everything tight. Yep, I like.

Ken H>

 

[Melsdad]

Thanks guys!

Ken the rotary table I have is a little over kill but I couldn't pass up the deal I got on it. It is a 16" troyke. This is how I got it. For reference it is sitting in a 55 gallon drum dolly I would like to get a 6" or 8" table somday but this does all i need and then some.

 

[KenH]

16"??? WOW - that's a big'un! I was thinking about the 6" size. I looked at a 4", but decided that was a tad small. I've got a X3 clone from grizzly.

 

[Plas62]

Nice work, Thanks for posting the WIP.