First build, control cavity plate issue

kipdurran

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Hello folks,

I think this is my first post. I have been visiting this site for several years hand have gotten hours of enjoyment from here.

This is my first scratch build. I have previously made a body from scratch but used a Warmoth bolt on neck. I have also done a LP Jr Precision kit that I just absolutely adore.

I thought it would be a great time to start a build from scratch. I have the Bartlett plans and his templates to build from.

Everything has been going great. I used a Robosander to shape the body, this was slower than a router but I think a lot safer from a tear out standpoint as I don't have a really great router table.

Routing the wire channel, switch cavity and control cavities went just fine.

Where I ran into a bit of a problem was with the rout for the control cavity cover. Because it is such a shallow route, the bearing for my Stew Mac bit was at the very top of the template. The problem happened because the silicone tubing that keeps the bearing in place was not against the collet and slid up allowing the bearing to slide up as well. This allowed the shank to ride against the template and consequently messed up the process. It messed up the template as well but thankfully I saw a thread here (sorry, I forgot whose thread it was) where they made copies of the templates just in case so I did as well. No biggie here, I will just make a new one.

My plan for saving this is to make a very slightly oversized control cavity plate. I don't think that anyone but me will ever know it.

I traced the control cavity from the template and scanned it into my computer and enlarged it slightly so it covers the errant routing completely.

How best to proceed from here? Ideally I would like to use just one template for both the plastic and the wood so it fits perfectly. I have a thought that basically a control cavity cover is essentially a removable inlay so I have ordered a router inlay kit. Am I thinking along the right lines? Is there an easier or better way?

Thanks for any input.

Steve
 

emoney

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The safest way is to use a thicker piece of mdf (or whatever material) and make a deeper
template. I ordered a shallower router bit to handle the job, because I've done what you did
in the past. Make sure, in any case, that your bearing is secured to the top of the bit, even
if that means using more than one bearing above it. Those little "sleeves" are a Godsend.
 

bfcg

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Stand offs
Duplicate the template several times and stack.
Template following collar.
Just 3 solutions off the top of my head, I am sure there are many more.
I am not familiar with the templates that you mentioned but are you sure that they don't have built in offsets?
 

kipdurran

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Point of clarification: I am not aware of any available "oversized" templates. I am making my own by enlarging a diagram on the computer and then making an MDF routing template from that. Sorry if that was not clear. I would like to avoid having to make two templates because of the inherent mismatch that will be inevitable between the two.

This is the router inlay kit that I have on the way:

https://www.amazon.com/dp/B0012JI6H...=1491846972&sr=sr-1&keywords=router+inlay+kit

This apparently uses one template for both of the pieces that need routing.
 

pshupe

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That's correct. The larger bit and collet cut the cavity then the smaller bit cuts the cover. The trick is getting the difference in thickness that you want. The bigger bit has to have a thicker collet than the thinner bit. I do not like amazon for details about the item purchased. Does it say the difference in thickness between the two? You could put a couple of pieces of tape on the edge when you cut the cavity and test fit, but that should work.

Cheers Peter.
 

kipdurran

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bfcg

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Offsets are fine when making cavity covers for any guitar that does not require deviations in the profile. in the case of cloning a vintage LP, vintage LP "bursts did not have exact shape covers( most of the time) nor did they fit in the recess like an inlay. It all depends on how anal you want to be about a copy. Personally, I got bored with making perfect clones a long time ago and the only reason I still make faithful reproductions is because it just happens to be the methods and templates that I have developed over the years.
Grind the collar on the router base bushing to be stubby and you wont need a thicker template
or consumable bearings.
 

kipdurran

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That's correct. The larger bit and collet cut the cavity then the smaller bit cuts the cover. The trick is getting the difference in thickness that you want. The bigger bit has to have a thicker collet than the thinner bit. I do not like amazon for details about the item purchased. Does it say the difference in thickness between the two? You could put a couple of pieces of tape on the edge when you cut the cavity and test fit, but that should work.

Cheers Peter.


I suspect that this is designed to have as little clearance as possible between the inlay and the routed cavity. I am fine with that as I can use tape as you suggested to give a bit of space, or just slightly sand the edges of the cover.

In an event, I am going to practice on scrap first.
 

ARandall

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I've done a fill and rerout to regular shape before. All you need is a darker back and you'll see nothing amiss.
 

kipdurran

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Well, great news.

The router inlay kit arrived last night and I did some experimenting.

I will refer to a negative template as the routing template that has a hole in it such as used for routing a cavity, and a positive template as the inverse of this.

So I started by taking the slightly enlarged control plate template that I made on the computer and glued this to 1/2 in. MDF and shaped that on my spindle sander.

This positive template gets mounted to another board. It will have to be thin such as 1/4 in. MDF or hardboard, etc. With the collar bearing off of the router, a run this around the positive template to create a temporary oversize negative template.

Next, install the collar bearing and use this negative template to make another negative template that is the same size as the positive template. (Whew.... wrap your head around that!). That will have to be thin as well.

From there I will use a pattern bit to make a copy of that onto 1/2 in. or thicker MDF to use as the final template.

That will leave me with a positive template to shape the plastic and a negative template to re-route the body. I will probably have to sand the edges of the plastic to allow a small gap all the way around but I am fine with that.
 

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