Toolpost Grinders

[SmithDoor]

If you read the Domore manual i posted it bolts to the compound it also show angel to compound for feeding.

Dave

How many of you have toolpost grinders? This seems to be a misnomer, because 90% of what is available requires that you remove the topslide and mount the grinder to the compound rest. They don't really fit on the toolpost at all. What do you use them for? How often do you use them? Every once in a while I get the urge to buy one, but honestly, the only thing I can think of using them for is to part of sections of cast iron tubing to make piston rings, or to grind the face of a valve. I don't generally have problems with valves not sealing although the quality of a tool turned valve face looks fairly horrible under magnification but proper lapping into the valve seat seems to work good enough to make the valve seal well. I can't really think of any situation where I would use inside grinding capability. They range in price from $200 for the Little Machine Shop style, up to $3000 for the Dumore brand.---Brian

 

[ignator]

How many of you have toolpost grinders? This seems to be a misnomer, because 90% of what is available requires that you remove the topslide and mount the grinder to the compound rest. They don't really fit on the toolpost at all. What do you use them for? How often do you use them? Every once in a while I get the urge to buy one, but honestly, the only thing I can think of using them for is to part of sections of cast iron tubing to make piston rings, or to grind the face of a valve. I don't generally have problems with valves not sealing although the quality of a tool turned valve face looks fairly horrible under magnification but proper lapping into the valve seat seems to work good enough to make the valve seal well. I can't really think of any situation where I would use inside grinding capability. They range in price from $200 for the Little Machine Shop style, up to $3000 for the Dumore brand.---Brian

I have been using my toolpost grinder the past two months. One project was repairing the lathes spindle adapter, that converts the spindle hole to a Morse Taper socket, for center work. It was made wrong and never fit from day one. It's hardened, and that's where grinding comes in. The other project was grinding the surface grinder spindle taper to get rid of runout. That machine never had good surface finish from day one. It was rebadged under many different names but search for "MJ7115 surface grinder". It's a bit light duty, and any out of balance wheel produces poor surface finish. I did improve that greatly by installing angular contact bearings, and then grinding the spindle taper on my lathe with the tool post grinder. This taper is the common 3 inches per foot type. But that project put me down the path of making the compound angle setting improvement, as the side of the compound was not parallel to the dovetail slide. And I was using an indicator to accurately set the compound. Still not perfect, but better.
I got my tool post grinder when Enco was still in business. It's an import from 1991, Czechoslovakia. And it does not use any standard taper so any additional tooling is home built. I now have to build a long reach internal grinding arbor so I can true up that #4MT hole, as I'm sure it runs an eccentric after fixing the outside of the adapter. That adapter is a 90mm metric taper, which is common in the European lathe market, and and accidental import to the USA. It had the major diameter about 4 thousands too small, it appeared to sit in the spindle, but rocked, and with a lathe center sitting another 2 inches from the front face, that error of concentricity was unacceptable.
So I guess, my use of a toolpost grinder is to fix my other cheap tools. But I know it can do more, I just haven't gotten out of fixing the preassembled kits I have.
I did make a balancing arbor with it last. So another tool to fix the out-of-balance grinding wheels.

 

[werowance]

here is mine. bought it on ebay. use it for grinding very small shafts and making needle valve etc.

bottom photo is from the ebay posting back when i bought it.

uses a router head as the motor. works pretty good for what i use it for. have used it to part very thin pieces of metal with a cutoff wheel so i dont end up with that lip that i usually get when using a parting tool.

this one was cheap and he makes them in axa and bxa that i know of. probably other sizes as well.