# Template Guide Bushing Interference



## thawey (Aug 15, 2017)

This may be a simple answer, but wanted to check with the resident experts around here.

I am creating a router table and using the Jessem MDF Template to create the opening for the router lift. The instructions call for a 3/4" O.D. template guide bushing with a 1/2" straight cut router bit.

As you'll see in the attached pictures, I am not getting enough depth out of the cut and the lock nut is actually coming in contact with the brass template guide which as you can guess, is causing the bushing to loosen.

My question is, should I look at getting a longer bit or is there an extension that can be used?

Thanks in advance.


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## Mike (Nov 22, 2004)

Tanner, you have a couple of options on this. The easiest route is to buy a longer bit. I always recommend to new members that they buy guide bushings with all 1/4" height bushings for exactly this reason. You can cut yours down to a hair under 1/4" height. An extension will not help in this situation as it would hit the bushing too.


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## hawkeye10 (Jul 28, 2015)

You either need a longer bit or a shorter shoulder on your template guide bushing. As for the nut on the guide bushing coming loose I don't understand what is going on but it shouldn't come loose.


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## thawey (Aug 15, 2017)

Thanks Mike, that was my initial thought - get a longer bit.

You also reference the height of the bushing, this I was not aware of as my local store didn't have variable heights for the bushings. I'll start with the bit first and then look in to adjusting the bushing height as needed.

All the best.


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## thawey (Aug 15, 2017)

hawkeye10 said:


> You either need a longer bit or a shorter shoulder on your template guide bushing. As for the nut on the guide bushing coming loose I don't understand what is going on but it shouldn't come loose.


As the router was spinning, it came in contact with the guide bushing which loosened it up.


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## DesertRatTom (Jul 3, 2012)

I think I had to buy the 1/4 bushing set from Woodcraft. I had to do some searching to find them. As to a bit hitting the bushing. That is a function of centering the base on the router, which requires a centering cone. The cone has a shaft, which you place in the collet, then fit the base down on the cone until it meets the router's bottom. Put the bolts in and it's centered. If the removable base comes loose, it can shift and the bit will hit the bushing.

Unless something else is going on, re-centering the base is the first order of business.


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## Cherryville Chuck (Sep 28, 2010)

If you shorten the guide bushing you can use thinner material for a template which will give you effectively more reach. 1/4" material is usually good enough for templates so the guide bush only needs to be 7/32" long. I've never figured out yet why some of them are so long becuase even if you use a thicker template you still don't need a long guide bush.

One other strategy you can use is to rout as much as you can with the setup you have. This will leave your work to a finished shape but only to a partial depth. You can then thake the work and flip it upside down on the table and use a flush trim bit instead of a guide bushing. The flush trim bit will follow what has already been routed.


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## thawey (Aug 15, 2017)

DesertRatTom said:


> I think I had to buy the 1/4 bushing set from Woodcraft. I had to do some searching to find them. As to a bit hitting the bushing. That is a function of centering the base on the router, which requires a centering cone. The cone has a shaft, which you place in the collet, then fit the base down on the cone until it meets the router's bottom. Put the bolts in and it's centered. If the removable base comes loose, it can shift and the bit will hit the bushing.
> 
> Unless something else is going on, re-centering the base is the first order of business.


It's not the bit that's hitting the bushing, it's the lock nut hitting the bushing (see first pic). I do have the centering cone and have completed that as part of the initial router set up.

I will look in to the Woodcraft set if a longer bit doesn't solve the initial problem.




Cherryville Chuck said:


> If you shorten the guide bushing you can use thinner material for a template which will give you effectively more reach. 1/4" material is usually good enough for templates so the guide bush only needs to be 7/32" long. I've never figured out yet why some of them are so long becuase even if you use a thicker template you still don't need a long guide bush.
> 
> One other strategy you can use is to rout as much as you can with the setup you have. This will leave your work to a finished shape but only to a partial depth. You can then thake the work and flip it upside down on the table and use a flush trim bit instead of a guide bushing. The flush trim bit will follow what has already been routed.


I agree, the guide bushing is far too long, but I don't have the ability to make a thinner template as it is a pre-made one provided by Jessem and it is quite thick. So, with the thick template and deep throat of the guide bushing, I am certain I need a longer bit.

Good tip, I will definitely add this to the list of items to try.

Thank you all for your insights, I can already see this is a great community with a lot of support.


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## kp91 (Sep 10, 2004)

The belt sander does a great job of shortening brass template guides


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## thawey (Aug 15, 2017)

Problem solved with a longer bit - thank you for all the recommendations.


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## harrysin (Jan 15, 2007)

thawey said:


> This may be a simple answer, but wanted to check with the resident experts around here.
> 
> I am creating a router table and using the Jessem MDF Template to create the opening for the router lift. The instructions call for a 3/4" O.D. template guide bushing with a 1/2" straight cut router bit.
> 
> ...


This is the very reason that I advocate the use of LARGE template guides. I design most of my templates for use with a 40mm guide which not only allows the chuck to pass through the guide but also allows the operator to SEE what the bit is doing. Another advantage is that the swarf clears rather than build up and cause extra heat.
When designing female templates the simple formula is: guide dia. minus bit dia. plus the size of the final cutout equals the cutout size in the template.


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## vindaloo (May 30, 2009)

harrysin said:


> This is the very reason that I advocate the use of LARGE template guides.............


That must be why most routers come with a 30mm bush. To allow the collet to go through. Never thought of that, just got annoyed. Now I'm not annoyed


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