matey said:hi all i used to work for a company that produced sheet metal parts for the aircraft industry, they used to rout parts using hss bit that ran either round the outside or inside of template to produce a replica of template.
i have 2 starter sets of bits in 1/4 &1/2 inch shanks but do not seem to have a bit for reproducing templates.
if i wish to cut an appeture right through a piece of 19mm mdf which i am using to get used to use of router, the only bit i seem to have is straight 1/4 dia X1inch the rest are mainly bottom bearing bits for edge work.
i am unsure wether to purchase a top bearing straight cutter that can be used to follow a template inside or out ,using plunge router or inverted in table,???
Woodnut has responded to your posting with good advice regarding routing with templates that are cut to exactly the same size as the finished item. There is an alternative method, and that is the method I use extensively. Prepare a template that is smaller when using a Male template and one larger when using a female template the use a template guide with a simple straight cutter each time or you may wish to add a moulding at the same time therefore you can use a beading cutter without a bearing.
The following drawings may help you. The first was to prepare a template to rout the external edge of a tray. the following two, I was preparing a template to rout the internal curve and a template to rout the external curve of a dining room chair top rail.