Most guide bushes are of steel construction but Trend offer three boxed sets of plastic bushes. Set 1 is metric in even sizes from 10mm to 32mm, Set 2 is in odd sizes from 11mm to 33mm, and Set 3 is in Imperial sizes from 3/8in to 1 5/16in. These sets offer an economical way of acquiring guide bushes; if you find yourself constantly using a particular size you can buy the steel version.

The subject is a large one and in this article I deal with the basics. In subsequent articles I will expand on guide bush applications and the making of templates. Tip. When you have located the fixing holes the first time you fit the Unibase, mark them with a dab of paint to speed the process on future occasions. Whether the template has to be made that much larger, or that much smaller, than the final product depends on whether the template is an ‘inside’ one or an ‘outside’ one. With an inside template the cut is smaller than the template but with an outside cut the cut is larger than the template. In the USA, guide bushes have traditionally been of two-part construction with a circular bush held by means of a threaded ring through a hole in the router sole plate. This type of bush has been creeping into the UK with the spread of Leigh and De Walt dovetail jigs, and has now got to the stage of Trend offering them in a range of diameters. Trend also offer a special circular sub-base to mount these bushes. Most guide bushes are fitted to the router base by means of two 5mm machine screws in threaded holes in the base casting. With some models, however, and not only the cheaper ones, fixing is by means of nuts and bolts through plain holes or by screwing into threaded inserts in the plastic dust extractor spout. This can lead to non-concentricity in the bush, make it difficult to tighten the collet nut, and seriously increases the time and effort involved in fitting and removing guide bushes. This, in turn, discourages the more creative uses where cuts are positioned and repositioned by changing the guide bush, the cutter, or both.When we come to guide-bush work with home-made jigs and templates we have to consider two factors which do not arise with commercial devices:

Making simple jigs and templates for use with guide bushes has a spectacular effect on bringing your router to life and opening up possibilities of creative work. Generally speaking, fitting a guide bush to your router reduces the efficiency of the dust extraction. The exceptions are those few routers designed with dust extraction as a priority and guide bushes that support good extraction. The best examples, in my experience, are the De Walt DW 621 and the Festool 1400 and 2200 models, with their built-in dust extraction and guide bushes designed in skeleton form.If you plan to do much guide-bush work with MDF or one of the irritant hardwoods, you would do well to consider the dust extraction question very seriously. See in our online shop the Trend Unibase and the Trend Circular Sub-Base) The Trend circular sub-base fitted to the DW 625 router