DIY Belt Grinder Build Questions

mikey said:
I suggest you epoxy on a platen liner now, before you dish your steel platen. I promise you that you will not regret this. If you can, drill and tap for two screws to support the liner before you epoxy it on. I suggest JB Weld.
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I learned the hard way about the platen. It only took a month or two before the platen was significantly eroded. The ceramic glass platen is a very good thing to add. I can't detect any wear on the glass platen.

Your grinder looks amazing. Nice job.
 
WobblyHand said:
I learned the hard way about the platen. It only took a month or two before the platen was significantly eroded. The ceramic glass platen is a very good thing to add. I can't detect any wear on the glass platen.

Your grinder looks amazing. Nice job.
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Just what is it you guys are grinding that causes the platen to erode? I have a Delta/Rockwell 6x 48 belt sander with a 12" disk. I use it on a regular basis. It's been in my shop for over 20 years, and both the belt and disk platen are in good shape. The belt platen does have some marks on it where the previous owner ran it into the belt, but other than that it's in good shape. I might add this machine was built in either the late 1950's or early 1960's, so it's been in use 60 years or better.
 
Grinding HSS lathe tools. Platen was not hardened steel, just some sort of cast steel. First the paint wore away, then the steel started getting divots. For general use, and for wider pieces which reduce the contact forces, I bet a regular platen would last a long time. For grinding HSS and cobalt tooling a ceramic glass platen is better. Hey it's a sample of one, but that's my experience.
 
projectnut said:
Just what is it you guys are grinding that causes the platen to erode? I have a Delta/Rockwell 6x 48 belt sander with a 12" disk. I use it on a regular basis. It's been in my shop for over 20 years, and both the belt and disk platen are in good shape. The belt platen does have some marks on it where the previous owner ran it into the belt, but other than that it's in good shape. I might add this machine was built in either the late 1950's or early 1960's, so it's been in use 60 years or better.
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A lot of us use belt sanders for tool grinding that requires a truly flat platen to create a truly flat face on the tool. I know from long experience that I can dish out a steel platen grinding lathe tools in a week or less, whereas a glass platen will last for a decade or more without any significant wear.
 
mikey said:
A lot of us use belt sanders for tool grinding that requires a truly flat platen to create a truly flat face on the tool. I know from long experience that I can dish out a steel platen grinding lathe tools in a week or less, whereas a glass platen will last for a decade or more without any significant wear.
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That's interesting. While I do use my Delta/Rockwell grinder for a number of other things it's primary function is to either create new form tooling from HSS blanks, or to sharpen existing tooling. It spent it's previous 40+ years in one of the machine shops at work providing the same service. That's a total time of close to 60 years either sharpening or creating HSS tooling.

After reading a few posts regarding the platen dishing I went into the shop and put a straight edge across both the belt and disk platens. I couldn't force an .001" feeler gauge between the straight edge and either platen anywhere. I have no idea what the platens are made out of, but they do carry the OEM part number so they are either originals or factory replacements.
 
Most 6x48 sanders don’t have the same belt speed as a 2x72, less heat. Could it be cast iron vs mild steel?
 
projectnut said:
That's interesting. While I do use my Delta/Rockwell grinder for a number of other things it's primary function is to either create new form tooling from HSS blanks, or to sharpen existing tooling. It spent it's previous 40+ years in one of the machine shops at work providing the same service. That's a total time of close to 60 years either sharpening or creating HSS tooling.

After reading a few posts regarding the platen dishing I went into the shop and put a straight edge across both the belt and disk platens. I couldn't force an .001" feeler gauge between the straight edge and either platen anywhere. I have no idea what the platens are made out of, but they do carry the OEM part number so they are either originals or factory replacements.
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I dunno', might just be that my belt sander platen was cheap junk steel but I had to replace mine too many times. In contrast, my first glass platen lasted over 11 years and remained dead flat despite grinding hundreds of HSS tools on it. I am now on my second glass platen and expect it to go for at least the next decade or more.
 
I completed the glass platen mount. It is ready for the glass platen which should be arriving shortly.

I made the shelf 0.180" thick since the platen is 0.192" thick. I'm hoping that enough clearance.

Also, I used 4-40 screws to hold the shelf in place. I'm hoping that's strong enough. I didn't want to go bigger since there would be very little material left from the countersink for the flat head screws.


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That should work fine. Be sure to rough up the platen and glass where they contact with some sandpaper before you clean and epoxy them together. I just use some 80 grit paper to put some scratches on them, blow off the dust and then clean with lacquer thinner before applying the JB Weld.

I use precision ground flat stock as a platen so I just used spring clamps to hold the platen and liner together. Some folks use tape, others just a weight and still others recommend no weight at all. The latter are using some not-so-flat mild steel and have experienced cracking of the liner when using clamps.
 
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