Q.: I have to drill a large number of 5/8" to 11/8" holes in reinforced concrete on vertical surfaces for embedding steel rods using epoxy. Many must be drilled above shoulder height, sometimes while on a ladder. It's very difficult and dangerous to drill these holes, and accuracy is also a problem. Do you know of a vacuum-base stand that can be used with a roto-hammer? I have a coring drill but cannot use such a setup because the holes must be drilled dry.
A.: Various manufacturers offer equipment that might be useful to you, but you may have to switch from roto-hammer to dry-core drilling. As is often the case, the difficulty is in finding the information you need to make a decision. One good source is the Hilti Web site, www.hilti.com.
Hilti offers a stand with its diamond coring systems that can be used horizontally or vertically. It can be anchored by vacuum, but using an anchor bolt or two is recommended. To find the Web listing, select "products" from the menu bar. Then click on "products" under Diamond Coring and Cutting, click on "Diamond Coring," then click on "Diamond Coring Systems" for the DD100 offerings. The stand is pictured being used on a wall above shoulder height with the DD100-MEC, which is a wet system. However, the same stand can be used with the DD100 dry system.
Milwaukee Electric Tool also offers a variety of equipment (www.mil-electric-tool.com), however our search did not yield a vacuum stand listing on its Web site.
Regardless of the brand of equipment, switching to diamond core drilling rather than an impact drill should also help in the accuracy department.