Increasing the M12v’s throat opening with a surprise twist. PICS

Howdy All,

Recently a friend of mine complained to me that his Hitachi M12v didn’t have a large enough throat opening to accommodate the larger horizontal panel raising bits. It’s a simple process to cut the offending template bushing “ears” off but what if you wanted to use a template bushing after removing these “ears”, you’re out of luck.

I’ve come up with a very simple way to solve the problem of removing the template bushing ears by replacing them with a lexan sub base. So now you can remove the offending ears and still use a standard Porter Cable set of template bushings.

Rather than try to explain my remedy for this obstacle over the phone I decided to put it in picture form. I hope that it helps others who may have the same issues.

It’s a simple process to remove the template bushing ears; I removed mine by simply cutting them off with a jig saw and a metal blade. Of course the base assembly was removed from the router first.

One must be careful not to remove too much material in this area and compromise the structural integrity of the router base. Careful machining and sanding results in a nice clean opening.

With the ears removed I can now concentrate on making a new base plate for the router that will hold the template bushing. By the way, I prefer to use the standard 1 3/8” Porter Cable type template bushing and the brass bushings seem to hold together a lot better than the regular steel ones.

My new base plate material is a piece of ¼” Lexan that was laying around the shop and is perfect for this, it wears well, easy to machine with woodworking tools and is almost bullet proof. The original base plate was removed from the router and clamped onto the new blank in order to accurately drill the mounting holes; care must be taken here when drilling these holes to assure a perfect fit to the router base.

Once the holes are drilled, the footprint of the original base plate is traced onto the new blank to be cut out later. Best to do it now while it’s all clamped together. There is one more machining step to do before I can proceed, the blank is now flipped over and the holes that were just drilled are countersunk to accommodate the original base screws.

With the blank now installed on the router the next step is to install a ¼” spiral bit into the router. I’ve chosen this size router bit because it matches the pilot drill bit in the mandrel of my hole saw set, more about that in a minute. The spiral bit is plunged through the Lexan and then the blank is removed from the router.

The next step for me was to place the blank “bottom side” up on the drill press table. The bottom side is the surface with the countersunk screw holes facing up. The ¼” pilot bit in the mandrel of my hole saw is lined up perfectly with the ¼” hole that was plunged by the router and clamped securely to the drill press table. The size of the hole saw that is required to make the through hole in the blank is 1 3/16”. This is the size of hole that is required for my Porter Cable type template bushings.

Once this through hole is drilled, the hole saw is removed from the drill press chuck and replaced with a 1 3/8” forstner bit. The 1 3/8” forstner bit will provide a very clean and accurate hole for the template bushing to fit into. Care must be taken to drill this hole to the right depth, I’m looking for the bushing to “just” sit shy of the surface of the Lexan.

From start to finish attention to careful machining will yield this as a result. Take my word for it; the router bit is exactly centered in the opening.

All in all, this is simply just one way of solving the problem of accommodating using large router bits in a router that doesn’t have a large factory opening and still being able to do template routing. The tools that were required were few and found in almost every woodworking shop. What you may not have doesn’t cost very much to procure. Hope this helps.

All the best
Gord