Welded construction for surface grinder arbor?

[akjeff]

During the time spent rough cutting stock, preheating, welding, post heating, and still having to finish machine it; you could probably make 2 or 3 three of them by simply starting with the appropriate sized solid bar, and just turn them to size. Granted that makes for a lot of swarf, but the time saved would outweigh the waste material IMHO.

 

[Flynth]

During the time spent rough cutting stock, preheating, welding, post heating, and still having to finish machine it; you could probably make 2 or 3 three of them by simply starting with the appropriate sized solid bar, and just turn them to size. Granted that makes for a lot of swarf, but the time saved would outweigh the waste material IMHO.

Yes, that's right. I originally misremembered that the portion the wheel goes on was 25mm (an inch) while it's really twice that. This changed things a lot in favor of just starting with a piece of 90-few mm bar. It is most likely I'll do just that.

 

[akjeff]

Just looked up that grinder, and it looks like a stout machine! 3hp and 8"x19" work envelope.

 

[Flynth]

Just looked up that grinder, and it looks like a stout machine! 3hp and 8"x19" work envelope.

Yes and it weights 3700lbs (1700kg). I was quite lucky to find it at such a low price.

I started on the wheel hub/arbor. It has lots of features...



This side is done. Next it will be parted (half way on the lathe, the rest on the bandsaw.). Then the taper needs to be cut and face grooving will happed

 

[woodchucker]

I'm betting that original is shrink fit with a step. I think that's how they get the weights in there. They put them in while putting the backplate onto the shaft.

Just a guess, but those are captive and you turn the screw to press them to the backplate.

just my humble opinion.

 

[Flynth]

I'm betting that original is shrink fit with a step. I think that's how they get the weights in there. They put them in while putting the backplate onto the shaft.

Just a guess, but those are captive and you turn the screw to press them to the backplate.

just my humble opinion.

The original is made from one piece(as far as I can tell). It may not be obvious on the photo, but those weights are cut lengthwise across the grub screw slit. If you remove the screw you can pull halves out easily. That's why they're numbered. To know which one mates with which.

I considered other options just as a material saving measure, but it stopped making sense once I realised the smaller diameter is not as small as I originally thought.

I plan to grind a hss face grooving tool and attempt to make those dovetail cuts on the lathe. The mill with a rotary table plus dovetail cutter being a second option.

 

[woodchucker]

The original is made from one piece(as far as I can tell). It may not be obvious on the photo, but those weights are cut lengthwise across the grub screw slit. If you remove the screw you can pull halves out easily. That's why they're numbered. To know which one mates with which.

I considered other options just as a material saving measure, but it stopped making sense once I realised the smaller diameter is not as small as I originally thought.

I plan to grind a hss face grooving tool and attempt to make those dovetail cuts on the lathe. The mill with a rotary table plus dovetail cutter being a second option.

Thanks, I didn't see that originally. I can see that now. Interesting way.. I would guess one of the threaded items is tapered, either the hole or screw?

 

[Flynth]

Thanks, I didn't see that originally. I can see that now. Interesting way.. I would guess one of the threaded items is tapered, either the hole or screw?

The walls of the groove weights ride in are tapered. If you were looking at a cross section the groove is much wider at the bottom than at its open top. Then grub screws push the weights against that.

It is a nice solution when you're using it. It allows you to move the weights anywhere. It is not so good when you have to machine another one... First the groove is a challenge. Then those weights.

To make them I think I'll have to make two concentric rings with a light press fit. Fit them together. Then drill and tap. Finally cut them out. Good part of that process is that I'll get spare weights so I'll not have to repeat it for more wheel hubs.

Just making that hub to this stage, and a nut, was lots of work(3 separate threads, 2 internal, face exactly perpendicular to the cylinder, undercut etc) . I wonder how much time it took them to do it originally in 1960-s with no Cnc (certainly in Poland) and with tight tolerances. I wouldn't be surprised if they did it by hand exactly as I'm doing it now.

 

[woodchucker]

Thanks, I'll be making a few for my surface grinder as well. I have a Delta - Milwaukee tool /surface grinder. The hubs are not standard, and are very expensive. Sopko lists them, but they are not in stock. I bought a rod of 3 inch or 3.5 inch 1144. I might try the 2 piece method and do the weights as one piece rather than split. And when pushing the arbor into the backing, capture them. Seems like it would be the way to go. And I would not pin them together. Rather I would create a chamfer on the wheel side of the backing plate, and just silver solder it. That's all that would be needed.
I think the multi piece hub is a better way to go, so if I mess up a part, I am not out the entire large piece. And that way I can make more. I have a bunch of thin wheels, so I can make short and also cup and diamond holders.
Your idea has been quite helpful thanks.

 

[jwmelvin]

The hubs are not standard, and are very expensive. Sopko lists them, but they are not in stock.

No kidding, right? They do stock or will make them but they’re ~$340 a piece.