Just finished a total refurb on my Jones & Shipman, but need to grind the Eclipse mag chuck. Did a rough grind of the rusty bottom first, but wasnt too impressed with the burn marks and could feel actual ridges. Not sure of the wheel I have in, but I know the finish will not be a good one for the mag chuck reference plane. Only thing I see about the current wheel is grey, and yes I did dress it, but maybe picked up some crud. Also, the small almost "faking like" marks a wheel leaves, are these maybe an imbalance issue? Thanks guys
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Grinding the mag chuck
- Thread starter Saxguy
- Start date
A picture could tell a lot. Grinding the mag chuck will be a challenge to say the least. You are working the grinder to its maximum envelope. You are gonna want to make sure your using a proper wheel. To soft you won’t get through the whole chuck without the wheel edge wearing out. To hard you will burn the chuck. Putting a burn spot in the chuck can ruin the chuck. Will have to regrind a fair amount off to get rid of a warp.
- Joined
- Aug 1, 2019
- Messages
- 337
Grinding a chuck isn't real complicated.
Use a soft wheel so you don't burn the surface. You can also use a small diameter medium hard wheel as the surface speed of the wheel is slower and it will cut softer. You don't need a mirror finish on your chuck, just a flat one with no chatter marks. Dress the wheel course by running the diamond across the wheel quickly, the wheel will cut cooler this way. I then use a wooden stick and run it across the wheel to remove any loose grains of abrasive. Turn on the chuck, in case there is any deflection when it is on. I use a Sharpie and put lines across the entire surface so you can tell when the surface has been completely ground. I also cover the entire surface with cutting wax (available from McMaster-Carr). At the very least use coolant. If your grinder has a coolant system, by all means, use it.
I will start my grind on the left side of the magnet so the grinding is a "climb cut" and then return to the left side along the same path as a "free cut". On my small Boyar-Shultz, I turn the cross feed two full turns and repeat the process. I "climb cut" because it generates less heat. Don't bang into the end stops!
When grinding out a hollow spot or truing up a new installation, take no more than .0004 / .0005 depth of cut to avoid heat build up. If you are getting heat buildup and warping, lift the wheel off of the magnet and reduce that amount. Crank the table at a brisk speed to avoid heat buildup and warpage. Apply a new coat of wax or coolant every time you complete the entire surface of the magnet. Once you clean up the complete surface redress the wheel as before and remark the entire surface. This time use the same technique but only take a .0001 / .0002 depth of cut. Finish by remarking the chuck with the Sharpie and take a free cut over the entire surface. Remember, you don't need a mirror finish, just a flat one with no chatter marks.
One final thought. When stoning dings out of your chuck (or mill table), stone the entire surface so the over time you don't stone a hollow spot into the surface!
Good luck,
Richard
Use a soft wheel so you don't burn the surface. You can also use a small diameter medium hard wheel as the surface speed of the wheel is slower and it will cut softer. You don't need a mirror finish on your chuck, just a flat one with no chatter marks. Dress the wheel course by running the diamond across the wheel quickly, the wheel will cut cooler this way. I then use a wooden stick and run it across the wheel to remove any loose grains of abrasive. Turn on the chuck, in case there is any deflection when it is on. I use a Sharpie and put lines across the entire surface so you can tell when the surface has been completely ground. I also cover the entire surface with cutting wax (available from McMaster-Carr). At the very least use coolant. If your grinder has a coolant system, by all means, use it.
I will start my grind on the left side of the magnet so the grinding is a "climb cut" and then return to the left side along the same path as a "free cut". On my small Boyar-Shultz, I turn the cross feed two full turns and repeat the process. I "climb cut" because it generates less heat. Don't bang into the end stops!
When grinding out a hollow spot or truing up a new installation, take no more than .0004 / .0005 depth of cut to avoid heat build up. If you are getting heat buildup and warping, lift the wheel off of the magnet and reduce that amount. Crank the table at a brisk speed to avoid heat buildup and warpage. Apply a new coat of wax or coolant every time you complete the entire surface of the magnet. Once you clean up the complete surface redress the wheel as before and remark the entire surface. This time use the same technique but only take a .0001 / .0002 depth of cut. Finish by remarking the chuck with the Sharpie and take a free cut over the entire surface. Remember, you don't need a mirror finish, just a flat one with no chatter marks.
One final thought. When stoning dings out of your chuck (or mill table), stone the entire surface so the over time you don't stone a hollow spot into the surface!
Good luck,
Richard
- Joined
- Jan 11, 2013
- Messages
- 1,821
Tom Lipton did some great videos about preparing and mounting a previously used magnetic chuck to your surface grinder..
Part 1
Part 2
Bernie
Part 1
Bernie
- Joined
- Nov 25, 2015
- Messages
- 8,313
Get yourself a wheel like this. The open structure is awesome, cool cutting, excellent.
And see this video:
And see this video:
- Joined
- Oct 29, 2014
- Messages
- 354
So I did this recently. Came out very nice The above posts provide good info and I cant really add much useful info but would offer the following advise. Set aside some time to do it. Its going to take a while, take very light cuts and dress the wheel frequently. Coolant is very helpful. My first attempt at this was years ago no coolant and no patience. I burned the chuck and that sucked. It takes a long time to clean that up taking .0005" a pass. Patience is important dont rush it
- Joined
- Aug 1, 2019
- Messages
- 337
By the way, if you have a back rail, don't forget to grind that also. I use a Norbide stick to dress and relieve the back side of the wheel.
richard
richard