Over the weekend I bought this Bridgeport 815 surface grinder for $250 and much to my surprise it appears to be nearly operable! Just have a few questions for anyone familiar with these machines or walker chucks.
The spindle: it has a 1.5" hub and looks to be a 3" TPF taper. Looks like it shouldn't be too hard to track down a 1.25 hub so I can use standard wheels. The hub has no nut, wouldn't be much work to make one but I really would rather have a 1.25 anyway. Is there any reason I shouldn't change it?
The chuck:Wouldn't hold at all. looked good on the outside but it had been infiltrated with water at some point and the metal strips underneath the magnet were in pretty bad shape. I replaced the two long ones which had corroded in half, the rest were intact so I left them alone. What is the purpose of these strips? They are about .010 thick, my replacements were .015 but it didn't look like the difference would matter. The magnet seemed a lot stronger with the new strips.
Also the springs weren't looking too good. They were partially corroded away but still looked strong enough to hold up the magnet when it's in the off position. Doesn't seem critical to me since when it's on the magnet is connected quite solidly to the top plate.
My main concern is the cam-link that actuates the magnet. The side that is connected the the handle had a slot rather than a hole. Not sure if that's how it is made or if it wore like that. My theory is that the magnet, being rather powerful, will probably find the sweet spot on its own given the freedom provided by slot slot. If I am wrong please inform me so I can make a new one.
When it was all cleaned and lubed it had holding power almost equal to the unabused chucks on the grinders where I work. I vehemently disagree with those who advise against servicing mag chucks. Mine work out fairly well all things considered. Just looking for a little advise in regard to my findings so I can proceed to optimize the chuck.
Also it's a 3 phase grinder. I use a fancy new Teco VFD on my Bridgeport, but I am figuring a solid state phase converter should be fine for this considering I won't be using it for extended periods.
I apologize for my lack of pictures of the inside of the chuck. I was pretty proud of my work and wish I would have thought to snap some photos! Next time.
The spindle: it has a 1.5" hub and looks to be a 3" TPF taper. Looks like it shouldn't be too hard to track down a 1.25 hub so I can use standard wheels. The hub has no nut, wouldn't be much work to make one but I really would rather have a 1.25 anyway. Is there any reason I shouldn't change it?
The chuck:Wouldn't hold at all. looked good on the outside but it had been infiltrated with water at some point and the metal strips underneath the magnet were in pretty bad shape. I replaced the two long ones which had corroded in half, the rest were intact so I left them alone. What is the purpose of these strips? They are about .010 thick, my replacements were .015 but it didn't look like the difference would matter. The magnet seemed a lot stronger with the new strips.
Also the springs weren't looking too good. They were partially corroded away but still looked strong enough to hold up the magnet when it's in the off position. Doesn't seem critical to me since when it's on the magnet is connected quite solidly to the top plate.
My main concern is the cam-link that actuates the magnet. The side that is connected the the handle had a slot rather than a hole. Not sure if that's how it is made or if it wore like that. My theory is that the magnet, being rather powerful, will probably find the sweet spot on its own given the freedom provided by slot slot. If I am wrong please inform me so I can make a new one.
When it was all cleaned and lubed it had holding power almost equal to the unabused chucks on the grinders where I work. I vehemently disagree with those who advise against servicing mag chucks. Mine work out fairly well all things considered. Just looking for a little advise in regard to my findings so I can proceed to optimize the chuck.
Also it's a 3 phase grinder. I use a fancy new Teco VFD on my Bridgeport, but I am figuring a solid state phase converter should be fine for this considering I won't be using it for extended periods.
I apologize for my lack of pictures of the inside of the chuck. I was pretty proud of my work and wish I would have thought to snap some photos! Next time.