# Routing templates with a small radius? Best template material?



## The_Beast (Mar 19, 2013)

I'm making a case out of a solid piece of wood. Basically, I'd have two templates. One to rout the outer edge and the ledge of the case. The second template would be lined up using the routed outer edge and would be used to rout out the cavity. What's the best way to rout out the ledge's small radii? The smallest pattern bit I can find has a diameter of 1/2" which is huge. What about using an inlay kit? Maybe just a chisel?


Here are some pictures to better explain what I'm asking:

























Also, what material makes a good template? I might be making 20+ of these cases and selling them so maybe an laser cut aluminum template?

Thanks for your help


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## jschaben (Apr 1, 2010)

Wow, that's some tight radii. I doubt you will find a pattern bit, at least an affordable one, smaller than 1/2". Since the bit shank is 1/4", the ID of the guide bearing needs to be 1/4", so that only leaves the 1/8" remaining to the bearings. 
I also don't see an inlay kit helping you. The guide bushing has got to be larger than the bit and if it encounters a corner with a radius smaller than the bushing radius, it just makes a turn and you are left with the radius of the bit. 
You should be able to get those radii in a numbered drill bit(s) and just drill the corners, then your templates would be mostly straight edges and it would free up your bit selection issues. 
Another option may (or may not) be to change the design a bit to open the corners up some.


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## jschaben (Apr 1, 2010)

Forgot the template material question. I generally just use 1/4" MDF but if you are planning on some laser cut ones, I like lexan. It's clear which helps visibility


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## The_Beast (Mar 19, 2013)

jschaben said:


> Wow, that's some tight radii. I doubt you will find a pattern bit, at least an affordable one, smaller than 1/2". Since the bit shank is 1/4", the ID of the guide bearing needs to be 1/4", so that only leaves the 1/8" remaining to the bearings.
> I also don't see an inlay kit helping you. The guide bushing has got to be larger than the bit and if it encounters a corner with a radius smaller than the bushing radius, it just makes a turn and you are left with the radius of the bit.
> You should be able to get those radii in a numbered drill bit(s) and just drill the corners, then your templates would be mostly straight edges and it would free up your bit selection issues.
> Another option may (or may not) be to change the design a bit to open the corners up some.



Yea, I designed the case to be milled out of aluminum by a machine shop, but I also kept woodworking in mind.

I see what you mean about router bushings/inlay kits. Even if I get this bushing and this router bit, I'd still be limited by the bushings 5/16 OD:
http://www.woodcraft.com/product/2004855/7671/516-od-x-14-id-bushing.aspx
http://www.woodcraft.com/product/20...00-upcut-spiral-router-bit-18d-12cl-14sh.aspx


The only problem I see with drill bits is that this ledge has to be flat. Unless they make drill bits that are flat like mills/pattern bits I don't see them working.


I'm guessing that I'm just going to have to suck it up, use a 1/2" dia. pattern bit and then chisel out and of the excess material.


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## jschaben (Apr 1, 2010)

Again, I don't know about sizes but brad points will give a reasonably flat bottom and the point can always be ground off. Doesn't sound like the job is a good fit for production quantities does it:blink:
Good Luck to you:smile:


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## banginonabudget (Feb 25, 2013)

Not sure what types of machines you have access to, but I see the possible access to Autocad there. Another option could be to get those blanks up on a mill and take out the corners with the mill and get the exact radius you want. That will leave you with a bunch of perfectly located holes. Then use those holes to somehow locate the router guides for the rest of the cutting (like locating pins). One of my buddy's does that and he can turn things around pretty quick. It kills two birds with one stone so to speak.

Also, depending on the size but I think a plexi or acrylic would be the best material. It will be relatively rugged and thermally stable at indoor temps. All your recesses from box to box should be very close dimensionally.


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## The_Beast (Mar 19, 2013)

banginonabudget said:


> Not sure what types of machines you have access to, but I see the possible access to Autocad there. Another option could be to get those blanks up on a mill and take out the corners with the mill and get the exact radius you want. That will leave you with a bunch of perfectly located holes. Then use those holes to somehow locate the router guides for the rest of the cutting (like locating pins). One of my buddy's does that and he can turn things around pretty quick. It kills two birds with one stone so to speak.
> 
> Also, depending on the size but I think a plexi or acrylic would be the best material. It will be relatively rugged and thermally stable at indoor temps. All your recesses from box to box should be very close dimensionally.


I wanted to avoid the machine shop if possible since I'd be trying to sell these for in order to fund other projects. Taking them to a machine shop would likely eat away a lot of these profits and not really leave me better off. 

My time is working on the weekends or after work, so it's free time which I would have otherwise wasted on Reddit. So I'd literately just be into these cases for the material used and any tools that I'd have to buy that I don't have. If I sold a single case, I'm guessing I could recoup all of my tooling cost for the rest of the cases I would make.


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## woodnthings (Jan 24, 2009)

*I'd make a drilling template to locate the radii*

Pre drill the holes using a drill template and then rout in between to get the straight edges. The drill guides would be of steel to prevent wear. Depth would be controlled by stops in the drill.

The template would be rather involved, but it's the only way I can think of to get those small radii. The interior could be routed away quickly using a larger dado cutter. Another template would contain the router base, probably a trim router. I don't see using bearing bits since there is not much to ride on.... :no:


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## banginonabudget (Feb 25, 2013)

The_Beast said:


> I wanted to avoid the machine shop if possible since I'd be trying to sell these for in order to fund other projects. Taking them to a machine shop would likely eat away a lot of these profits and not really leave me better off.
> 
> My time is working on the weekends or after work, so it's free time which I would have otherwise wasted on Reddit. So I'd literately just be into these cases for the material used and any tools that I'd have to buy that I don't have. If I sold a single case, I'm guessing I could recoup all of my tooling cost for the rest of the cases I would make.


Makes sense. I figured based on how you worded things about setting it up for multiple builds (on both wood and aluminum) and laser cutting you may have access to this stuff. Machine time would kill anything you would make off the top. 

As a possible alternative, how critical are the radiuses to your final product? Is there an insert that needs to fit into the recesses?

Sorry for the multiple questions, but I do multiple run product lines as my day job and woodworking as a hobby. Finally found something I may be able to input to. :laughing:


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## Dodis (Feb 25, 2013)

The Beast, (excuse the long-winded post)

Since you are already drawing this in AutoCAD, it would be easy to layout the design for a template to use guide bushings. 

First, to handle the small radius curves, a 1/8" straight bit will make those just fine (.0625 R.). And to make the math simple, plan on using a 3/8" guide bushing. 

So all you need to do is take your desired cut edge line, parallel copy it by 1/8", which is the distance from the edge of the cut of the 1/8" bit to the edge of the 3/8" guide bushing. This will make the rounded corners of the correct radius to give you the resulting .078" R. and .090" R. cuts. 

As for making the template itself, the aforementioned 1/4" MDF would be fine, the important part is paying close attention to getting the template cut accurately, or cut close and sand it to exact size. Best if you have access to a plotter would be to plot the template layout to full size, then glue it to your template board. And since you are doing two depths, then you would make two templates, leaving plenty of overhang around the outside to support the router, and glue some supporting material under the edge to both support the template and as a reference face to align the templates to the workpiece. Also, depending on the size of the opening, you may have to take a page from the router bowl playbook and add an oversize sub-base to span the distance of the opening in the template.

Now for the bulk of the routing, to clean out the tray, you can use the same bit to bushing measurement of 1/8", or the next size up for roughing, then when going to the 1/8" bit, it can do the final trim around the edges. An example would be to make use of a 1/2" bit, use a 3/4" bushing, or 7/8" bushing to leave the edges for the 1/8" bit to cleanup.

I did a similar layout that I posted on routerforums.com to route hex holes for nuts to build jig knobs, etc.
http://www.routerforums.com/jigs-fixtures/40381-accurate-hexagonal-holes-bolt-heads.html

Rather than have those interested have to go there to download, I have posted the plan and pics of the proof of concept here.


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## Futurepast (Jun 18, 2012)

Nice Dodis! I was looking to route some 1" hex bolts and you made it so I don't have to think about it


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## The_Beast (Mar 19, 2013)

Dodis said:


> The Beast, (excuse the long-winded post)
> 
> Since you are already drawing this in AutoCAD, it would be easy to layout the design for a template to use guide bushings.
> 
> ...



That's great! I thought that bushings limited the radius to the outside diameter of the bushing and not the bit. All I would have to do is off set the actual line by the distance between the outside dia. of the bushing and the dia. of the bit right?


Thanks again


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## Dodis (Feb 25, 2013)

Beast,

Yep, that's all it takes.

For some templates, you can also plan combinations of bit and bushing dia for different results, or sizes of routed areas.


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## The_Beast (Mar 19, 2013)

What's the best place to get 1/8" dia. cutters? I looked at woodcraft at upcut ones, but they're like $20. It's spend and I'll do it, but is there anything cheaper?


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## Dodis (Feb 25, 2013)

Funny, I replied last night and I guess it didn't make it...

The bit Have (in my pic above) is just an old HSS Craftsman that I have had for years, rarely used. Probably just a few bucks back then...

I did a quick look, and you can still get a 1/8" carbide at Sears for $11.04 with free store pickup... I guess I better order one myself too. All the others I saw were $14 and up.

http://www.craftsman.com/craftsman-1-8-in-straight-carbide-router-bit-1-4/p-00928614000P?prdNo=27


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## woodnthings (Jan 24, 2009)

*also H-F*

They have an inlay kit including the bushings with a carbide bit:
http://www.harborfreight.com/solid-brass-router-inlay-kit-99552.html


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## The_Beast (Mar 19, 2013)

Dodis said:


> Funny, I replied last night and I guess it didn't make it...
> 
> The bit Have (in my pic above) is just an old HSS Craftsman that I have had for years, rarely used. Probably just a few bucks back then...
> 
> ...


Nice, I didn't even think about ordering from there. I don't really order too many tools online (since I use a buddies shop and he has quite a few cool tools) and there are no bits like this at any local stores.




woodnthings said:


> They have an inlay kit including the bushings with a carbide bit:
> http://www.harborfreight.com/solid-brass-router-inlay-kit-99552.html


You may not know, but will this fit a Milwaukee 5615?

I'm pretty sure this is the one he has:
http://www.cpomilwaukee.com/milwauk...zmap=5615-20&gclid=COqd_dzlrrYCFc9AMgodxl4AgA


Also, I just wanna say thanks for all the help! I'm not a total noob when it comes to woodworking, but I still need some help some times. So thanks for helping me out


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## jschaben (Apr 1, 2010)

The_Beast said:


> What's the best place to get 1/8" dia. cutters? I looked at woodcraft at upcut ones, but they're like $20. It's spend and I'll do it, but is there anything cheaper?


They're $14 here with free shipping
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_solid.html


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