The guide bush is essentially a circular flange, usually between 10mm and 40mm outside diameter, which fixes to the router base and acts rather like a small ring fence. The cutter plunges through the middle of the bush and the outside edge of the ring runs against the jig or template, to position the cut.

With the hand-holds completed, they and the board’s edges are decorated with a 1/4in radius bearing-guided ovolo cutter. A selection of home-made jigs and templates with their guide 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. 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. The standard bushes also fit directly to the T3, T4 and T5 models, giving compatibility across the entire range. 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.Whenever I acquire a commercial jig I make a mounting board for it and I make it so that it looks as if it is designed for the jig in question. I cut handholds for carrying and hanging the jig, and I put a decorative moulding on the edges of the board and the handholds, with a bearing-guided cutter. Most of the popular boxed sets of this type of bush are pretty useless for general routing work because they have such a limited range of diameters, but the Trend range (which is in Imperial measure) is much more useful, running from 7/16in to 2 1/8in diameter. Examples include the Bosch GOF 2000 ACE, the new Festool OF 2200 EB, the Hitachi M12 V2 and the Triton TRA001 2000.

See in our online shop the Trend Unibase and the Trend Circular Sub-Base) The Trend circular sub-base fitted to the DW 625 routerThus with a guide bush of 20mm diameter and a cutter of 10mm diameter the offset is ½(20 – 10) = 5mm.

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. A bonus with both these plates is that they come with a centring bush and pin so you can ensure concentricity with the motor spindle. Some of the non-Trend routers that accept Trend guide bushes Regrettably, there is no standard size or fitting for guide bushes. The widest range by far is the Elu/ De Walt/Trend system, with a 60mm diameter plate attached to the router base with two 5mm countersunk screws. Most commercial jigs (whoever they are made by) come with a Trend-compatible bush as standard. They fit not only most routers from Elu, De Walt and Trend but also a number of other popular models. If your router does not accept these bushes, and does not include a bush of the required diameter in its own range, you have to make or buy an adaptor plate to take them. Trend offer two such plates: the Trend Unibase and the more expensive Circular Sub-base. The standard 60mm Trend bushes also fit a number of other medium-power routers, although their manufacturers tend not to publicise this point. Trend routers with a selection of their guide bushesCredit subject to status and affordability. Terms and conditions apply. Axminster Tool Centre Ltd trading as Axminster Tools is a credit broker and is Authorised and Regulated by the Financial Conduct Authority. Credit is provided by Novuna Personal Finance, a trading style of Mitsubishi HC Capital UK PLC, authorised and regulated by the Financial Conduct Authority. Financial Services Register no. 704348. 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. 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: The handholds are cut using a very simple home-made template, a 24mm guide bush, and an 8mm cutter. An example is a mounting board made for the Trend CDJ300 dovetail jig. The handhold is an ‘inside’ cut, so the template is bigger than the required hole. Details of the template and the cut will be given in a future article. The jig on the completed mounting board 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.