Cat head is giving very good advise. Proceed slowly and carefully. I recently rebuilt the spindle on my Ingar SG, with good results. I ended up making 7 different specialty tools (wrenches or pullers or pushers). It really is not a difficult task, just figure out how everything is supposed to go, and think through your steps carefully. In my case the a previous owner had installed conventional C3 grade bearings- which cost about $20. I was able to get the correct bearings from eBay and my local bearing house for a bit under $500 delivered.
All SG spindles are not the same. There are a number of different designs, but they are all trying to accomplish the same thing. If you can get the correct manual for your machine, then you are way ahead. If the manual you have does not represent your machine, then check out as many example SG spindle design as you can find.
I understand you pain that you spent over $1000 and now you need to put in considerable time/money to end up with a working grinder. Persevere - in many ways this is what hobby machining is. Getting machines working well is part of the game. If you end up with a good working surface grinder for $2000, then you have done well.
I am certainly very much a rookie grinder hand. I’ve got about 100 hours in and once I got the machine working well, it seemed I was about half way to getting good results with the SG. Hang in there, a surface grinder is an awesome machine - but there is a learning curve.
Let us know how you make out. David
