I had some problems with getting properly centered and accurate holes when I built mine since I had a crappy HF bench type drill press and even crappier drill vise at the time, which had a lot of chatter and slop, and a table that I couldn't keep level. Also i didnt have a lot of experience drilling/tapping metal where some level of precision was required. All of that combined left me with a lot of headaches and lack of confidence about my gib for a year or so.
In the long run, for me, it was good, since after rebuilding it a half dozen times, and making lots of modifications, I now have a deeper understanding of how these types of machines work, and feel confident fabing them from scratch. On the flip side, I've got more time and money in my gib than I would have buying a high end grinder.
For me its all ok, since I find myself more interested in making tools these days than making knives, but unless you feel the same, take the time to do things right the first time around.
The biggest thing you have to worry about is drilling the holes in the tension arm for the tracking assembly, and the cross hole for the piece that the tracking wheel attaches to, where it connects to the tension arm. If you don't get these drilled square and vertical, you'll have tracking problems. If you've got access to a large floor model drill, or better, I'd use it. Buy high quality twist drills, taps, and also countersinks from an industrial supplier. You can get by with just one 7/8 or 1" countersink, since the angle should be the same regardless of screw head size.
If you have a welder and are confident using it, there are a lot of things you can do to make the grinder nicer. I welded the main upright piece of the gib to the base, and I also countersunk the hole for tracking wheel bolt in from the back, and welded a 1/2 steel shoulder bolt with a flat socket head clamped square into it. I did the same thing with my platens for the various wheels. That combined with "shop" nuts, keeps all the wheels secured properly without having to put too much pressure on thr cheaper wheels that don't have sleeves between the bearings. When I had the tension wheel secured with a bolt screwing into a tapped hole, it was constantly coming loose and affecting tracking.
I posted in another thread about Ed Caffreys suggested mods to use a compression spring instead of a pull spring, and to move the tracking arm forward, and I recommend it highly.
Make sure you figure out how many and what length and size of hardware you need and try to make one trip. I bought tons of wrong sized bolts and made many trips to lowes, wasting gas time and money. Also, those places will always be missing something you need, and you can spend tons trying to make something else work, so if you've got an industrial/contractor supplier for these types of hardware, even if its out of your way, do yourself a favor. Also, all the bolts for the tooling arm receiver section aren't the same length.
Sorry to be so long winded.
