I've always found that if I hold the grinding wheel in my hand/fingers (builders gloves useful here) that provides enough friction to do the nuts up tightly.

I've always used just my hands to hold the wheel. I never found I had to tighten the nut more than that.

Pete

First off, the shaft is NOT in the wrong way round. Secondly it is completely correct to have a left hand thread at the left side of the shaft and a right hand thread at the right side of the shaft. This prevents the Clamping nuts working loose during use of the grinder. therefore you will never , ever be able to tighten the nuts by using a spanner at each end of the shaft. This , even if it were possible , which thank goodness it isn't, is absolutely NOT the way to tighten grinding wheels. It matters not that it's a cheap bench grinder, what matters is that before you play with it you MUST adhere to the correct wheel securing practice. If you don't you're in for disaster, , and believe me, I've seen a wheel burst and the resulting damage. Please get sound advice from possibly publications regarding securing and mounting grinding wheels but absolutely not from someone who says " just do it like this, I've been doing it for years and not had a burst wheel". Be safe before you play with potential life threatening tools. This is simple to do. Merely learn about them and understand them before you try using them. I'm not in anyway a H & S nut, but in this case I implore correct knowledge is sought and followed.

Hi, below is a summery of mounting precautions. Also a bit on guards.

Regards Nick.