Surface Grinding

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ctwo
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Re: Surface Grinding

Post by ctwo »

The flat part of the table measures 6" x 13.5" wide and the wheel barely clears that. I was tempted to get the 6x12" chuck but wasn't sure how much room the mounting hardware would take, and I was told it was a 5x10. Tell me this is a 6x12 grinder. The chuck just came, and who turned up the gravity?

I felt like having some fun. You'll notice this machine is missing the nameplate covering the belt. I was going to make a plate and call this the Hawaiian Five One O. That won't be funny if it's not a 510 grinder though. Well, maybe for you all :lol:
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jwmelvin
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Re: Surface Grinding

Post by jwmelvin »

I hear what you’re saying. I think my chuck is also a 5x10, though I’ve primarily been using the machine with the other attachments as a tool grinder.
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Harold_V
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Re: Surface Grinding

Post by Harold_V »

Interesting!
How does one mount the magnetic chuck? Grinders with which I am familiar have T slots at each end to accommodate clamps that restrain them. Your machine, aside from a line down the center, appears to have no means to clamp anything.

When sizing for a surface grinder, it's important that the wheel is able to completely clear all sides of the surface to be ground. If you are limited to a cross travel of only 6", there's no way that would be considered a 6" machine. 7" of travel? Certainly could be!

H
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GlennW
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Re: Surface Grinding

Post by GlennW »

Harold_V wrote: Wed May 18, 2022 1:33 amYour machine, aside from a line down the center, appears to have no means to clamp anything.
That image is a close up of vise jaws he ground that are clamped in the drill press vise that is mounted to the table.
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ctwo
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Re: Surface Grinding

Post by ctwo »

There is a T slot, for the smaller size T nuts that I don't have. After using the supplied bulky clamps to mount the 5x10 chuck, there is about 1/4" flat table left on either side of the clamp.

The wheel looks like it clears the 6x13" table pad, meaning it should be able to grind that entire area. I was just concerned about room to mount at each end, but would prefer the larger table. There would only be half an inch of mounting slot on each end, and no place for the clamp pivot to sit. The seller of course does not want to return the item.


The table measures within two all around.
Image

After dressing the wheel, the grind looks much better. This is a CR steel soft jaw. It is within two all around, but the ends are where it gets to the full two. It's bulged in the middle, or is narrower at each end by about a tenth. Someone would think the ends were getting warmer than the middle, but that seems very unlikely. Perhaps the table moves off the end a bit and sags, or the ways are worn at the ends. That seems more likely.

Image
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Harold_V
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Re: Surface Grinding

Post by Harold_V »

GlennW wrote: Wed May 18, 2022 4:58 am
Harold_V wrote: Wed May 18, 2022 1:33 amYour machine, aside from a line down the center, appears to have no means to clamp anything.
That image is a close up of vise jaws he ground that are clamped in the drill press vise that is mounted to the table.
I must really be losing it! Thanks, Glenn. It's perfectly obvious----yet I managed to miss it.

H
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Harold_V
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Re: Surface Grinding

Post by Harold_V »

The finish, in my estimation, has improved considerably. Frankly, it's an amazing finish considering the light-weight machine from which it came.

One of the things I look for in a finish is that there is no waviness, which you had previously. That's an indication of several possible reasons, most of which can be addressed by dressing the wheel (wheel not running true, wheel loaded, wheel dull). Depending on your method of grinding and the chosen wheel, those lines can be improved upon if you desire. Note that soft steel is far more prone to yielding that than hardened steel.

The difference in measurements CAN be due to the material. Like it or not, when you remove material from a part, the ends are inclined to move, displaying a part that is thicker in the center than the ends. It CAN be the result of heating as well. That's why I avoid dry grinding.

When you're trying to achieve flatness, the very best policy is to flip the part time and again, removing only miniscule amounts from each iteration. I generally don't even try to get a full surface when setting out. I try to remove the highs until there's a flat plane, then the part gets flipped and I do it again. Repeat until the part is fully ground on both faces. By doing so, you'll keep the internal stresses closely balanced, so the part isn't inclined to move as much. Strive for equal overall stock removal from each face.

Cold rolled material is very challenging due to the excessive stress as compared to hot rolled. Heat treated parts are generally more relaxed, due to the draw that is normally performed after heat treat (that isn't true for precipitation hardened materials). They move less but can still move due to the fact that a draw (the tempering cycle) is never taken high enough to fully relax the part (for obvious reasons).

If it hasn't been mentioned previously, the choice of wheel media for alloys is never silicon carbide, although it is the choice for cast iron. Aluminum oxide is the wheel for grinding steels, not taking into consideration modern abrasives, none of which have I experienced. Silicon carbide is generally the best choice for non-metallic objects should the need arise.

H
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ctwo
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Re: Surface Grinding

Post by ctwo »

Thank you, Harold. Hopefully photos are genuinely revealing. It would be great to improve the grain further. I'll have to figure out which wheel is on there.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
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ctwo
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Re: Surface Grinding

Post by ctwo »

Figured I could work on this v-block.

Image

I think it's always going to have some holes.

Image
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
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GlennW
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Re: Surface Grinding

Post by GlennW »

Once you get your chuck ground, you'll need a good Step Angle Block so you can square things up.
P1120002.JPG
A good one is money well spent if you hope to grind things square.

Good 1-2-3 Blocks can be helpful for squaring things as well with a little thought and careful setup.
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earlgo
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Re: Surface Grinding

Post by earlgo »

123 blocks are indeed handy especially if they are bolted together to be sure they don't move when setting things up. This pic shows squaring up a small block for a project. The small block was secured to the 123 block by a clamp that can be seen if one zooms in on the pic. It ended up square and parallel well within .001".
123blocks.jpg
The Delta Tool Maker manual says in order to have a good finish, the motor and pulley must be balanced together. This one came with a 3 phase motor and since I didn't have 3phase in my shop I used a 220v single phase and transferred the pulley to the new motor. I have never gotten what anyone else would call a good finish because it is obvious that the system is bouncing. I have found that if one makes several spark-out passes with a newly dressed wheel, the finish improves slightly.
--earlgo
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ctwo
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Re: Surface Grinding

Post by ctwo »

Groovy! The next surface was going to be the short one, and it was wobbling. Now I see how to clamp it to something else and solve both the wobbling and achieve square. I do have a nice step block, a couple 123 sets, and the right size screwless grinding vise.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...
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