The basic rules are applicable to all types of machines - from spindle molders to bandsaws. Basically, they all have a bed or table, castings, bearings, gears, and a motor.
Castings and Beds - These are the most essential components of a machine since you can replace everything else. Check for breakages and cracks. Small cracks can be stitch-welded in cast iron and there are local companies that can fabricate replacements. However, this does add hassle and cost, and there are many good machines that are already available that have sound castings.
A straight edge can be used to make sure the beds are flat. Machines that are heavily used might have scored or worn areas that can be re-ground. However, finding another machine that has a flat bed might be easier.
Don't worry about small dents or light rust. As long as the rust is not pitted you can use oil and wire wool to clean it off. If dents are big enough that your work has affected then a cold repair kit can be used to fill them.
Visit an auction to learn how they work. However, when you are ready to buy you should register and obtain a catalog check out industrial surplus, and then make sure you review the terms and conditions. Check for these points:
Hidden Costs: There is often a buyer's premium (commonly 10%) that gets added to your bid price.
Payment Terms: Usually an immediate deposit is required once the hammer falls and then full payment is due by the end of the day. The only acceptable forms of payment might be a banker's draft or cash.
Pick-Up: Once your final bid has been accepted, the lot is all yours. The auctioneer might want the machines to be off of his site on the same day. Delivery will not be included in your bid.
Viewing: There might be an open inspection on the day prior to the sale. Otherwise, you only have a brief amount of time before the auction starts. You should have the ability to handle the machine but don't expect to be able to use or start the machinery.
Guarantee: Usually, lots are sold as-is without any guarantee. Some auctioneers might allow a couple of hours following the sale to find any fatal faults.
Keep These Golden Rules In Mind:
1. Prior to the sale, determine what your price limit is and then stick with it.
2. Watch the lot numbers - it can be costly to bid on the wrong lot.
Gears and Bearings - Whenever you can, try out the machine before buying it. Feel and listen for clonking, grinding, or any other type of roughness. However, don't let that discourage you. Even in really old machines, usually, bearings are a standard size and are easy to replace.
If it seems to be a driver issue then the gears might be the problem. Replacing drive speed gearbox components will take more time than a direct rise and fall, but you can do either. Consider this when negotiating the price and then ask the seller to repair it as a condition of the sale.
Drive Belts and Motors - Specialist repair companies can rewind worn motors and it is easy to replace drive belts. So if you believe an old machine has been used too much, don't worry. Focus on the castings.
Accessories, Tools, And Guards - Be sure that the machine has all of the essential accessories and right guards. Your health depends on the guards, so walk away if they are not there.