# Modifying Rail and Stile cutting bits (window sash joinery)



## RepairmanJack (Aug 4, 2013)

Hi all, I'm building some replacement double-hung windows for my 1927 brick craftsman house. The most of the original windows are long gone, but I've still got a couple that have served as a guide for what I need to build. 

I've cut down salvage windows, rebuild existing windows, but this is my first excursion into complete, from scratch window sashes. 

My first "reproduction" test sash set is clamped and gluing up right now. Building these demonstrated that the stile and rail cutter set I purchased is going to cause me some grief when I build my "real" windows. 

I don't have a shaper, but I've got a 1/2 table router for the work. I using the CMT Orange 855.801.11 rail and stile set. It is pretty much identical to the Freud and Infinity tools set. These are pretty highly recommended sets, but I'm a tad disappointed.

#1 issue is that the coping bit seems to require removing an extra 1/8" from the tenons. Rather than a beefy 3/8" (original sized) tenon, the bit requires that I cut my tenons down to a piddly little 1/4" If I don't, the cope comes out wrong and the pieces don't join up properly 

I really don't like going down to 1/4" on a 1 3/8" thick sash. It seems especially small for Casement windows - which seems to be the main target for these bit makers. 

My question is... are there better sets out there for making reproduction windows with a 3/8" tenon, or am I simply being overly paranoid about using a 1/4" tenons. 

I figure I could glue a 1/8" cheek on the tenon to get the thickness back, but it would never be as strong as a real 3/8 tenon

Can these coping bits be safely modified for 3/8" tenon sizes (e.g. grinding off the top 1/8" of the head)? At over $100 for the set, I hesitate to ruin part of it. 

So far, I've made some gorgeous muntins but the joinery at the rails and stiles have been disappointing. With my reproduction 3/8" tenons, I've had to manually shave the profile, which weakens the joint and kinda defeats the point of have a coping bit at all. 

The rail cutter is really great - just wish I had some better options for the coping cutter.. 

Thanks for any replies.


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## Steve Neul (Sep 2, 2011)

I looked at the set on google images and what you are proposing would work. Unless you have the right tools with a diamond grinding wheel you will have to have your saw sharpen shop do it. Personally I don't see that it will make any difference. The tenon on that set isn't intended for strength but alignment. Either way if you just glue them together the joint won't last for decades like you want. The joints would also need to be doweled for a long lasting joint. In the old days they used a through mortise and tenon which made a good joint. With a set like that the only window joints I would use without a dowel would just on the divider bars.


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## RepairmanJack (Aug 4, 2013)

Thanks for weighing in. If I used the cutters as they are intended, there's no reason I could not go full-tenon, they'd just be really thin. 
I'd rather not go with dowels, but if there are no other good options and I'm stuck with a 1/4" tenon...

Guess the bottom line question is... are there better bit options for a 1/2" router table setup? It's the coping cutter that is really letting me down. Unfortunately, every set that I've found is is like the CMT kit (at best). Some don't even give you and option of keeping a tenon. I want to build my windows as historically accurate as possible, but I just can't justify the expense of a shaper for a limited number of projects (only building 4-6 window sets)


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## bladeburner (Jun 8, 2013)

Had a very similar problem and my workaround was floating tenons. Which, like pocket holes, is a technique I use whenever I can.

Floating tenons are easy for me, since I have a Woodrat, but I use to do them on my horizontal table too. Still do on really heavy stuff.

For some work, I miss my shaper!


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## Steve Neul (Sep 2, 2011)

You could remove the lower cutter on the sticking bit and just use it or a router table without the bearing or get an extra bearing to take the cutters place. Then you could rabbet the glass lip on your table saw any size you wish. The way the coping bit is made I don't see any reason you couldn't do a through mortise if you wanted. 

It's been so many years since I've made double hung windows. I seem to remember the hard part was the top rail of the lower window and the bottom rail of the upper window. The joint was something like a finger joint and the rail was thicker than the rest of the window with an angle on it so when the two windows closed together it was air tight. I'm out of town right now. When I get home on Saturday I will see if I can find my notes.


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## rrich (Jun 24, 2009)

In a word DON'T modify. Use the existing set up.

Strengthen the joints with dowels. 

Use this as a drill guide.

http://www.rockler.com/product.cfm?page=18088&site=ROCKLER

Don't mess with the loose tenons or shifting the drill guide part. This will give you nice square to the surface holes. Drill about 1-5/8" deep in each part and then use 2-1/2" dowels. (I prefer fluted dowels) After the holes are drilled then do the routing. 

With something like Tite Bond III, the house will fall down before the window frames fall apart.


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## RepairmanJack (Aug 4, 2013)

rrich said:


> In a word DON'T modify. Use the existing set up.
> Use this as a drill guide.
> 
> http://www.rockler.com/product.cfm?page=18088&site=ROCKLER


That's a nifty setup. However, mMy problem's not so much with making good mortise and tenon joints - particularly with butt-joints. I've got a mortising machine and lot's of experience cutting tenons. They turn out... ok. 

My real problem is finding a way to make the coped cut on one side of the rail, right above the tenon. This is the spec sheet for the set I've got. 

The pic below shows the problem (w/o measurements)
The tenon made with the coping bit requires your tenon to be no thicker than 1/4" otherwise the edges don't match. 










If that coping bit were 1/8" shorter, it'd be perfect.


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## RepairmanJack (Aug 4, 2013)

Steve Neul said:


> It's been so many years since I've made double hung windows. I seem to remember the hard part was the top rail of the lower window and the bottom rail of the upper window. The joint was something like a finger joint and the rail was thicker than the rest of the window with an angle on it so when the two windows closed together it was air tight. I'm out of town right now. When I get home on Saturday I will see if I can find my notes.


Yeah, the meeting rail was tricky. I left the rabbet cutter on and had to glue a replacement strip back into the wood. I'll probably remove the rabbet cutter next time.

---

I'm realizing that I can't modify the bit feasibly. That leaves me with grinding my own, living with a 1/4" tenon, or finding some other way to get my coped sticks...


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## Steve Neul (Sep 2, 2011)

This is what I have in my notes for making the joint for the meeting rail. We doweled the other rail but I don't see any reason the other rail couldn't be made with the same through mortise joint however I think I would use a hollow punch mortiser and make the tenon not as wide as the rail on that one.


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## RepairmanJack (Aug 4, 2013)

Steve, nice drawing. I've been working a side project and haven't checked back recently. Your drawing is pretty much what I made. I might cheat and glue the meeting rail on next time. 

I took a break from the double-hung windows and built a casement window from scratch. It came out pretty nice and I managed to get 3/8 tenons - but again the coped ends were not quite right. I still found myself cutting out the ogee profile on the rails. This is really bugging me. I was about to give up and buy a shaper, when something occurred to me. 

The rabbet cutter on the top of my CMT set is removable - to service the bearing. This bearing is a 608, double-shielded metric (7mm thick). The cope bit comes exactly to the bottom of the bearing and the rabbet cutter comes exactly to the top. My tennons have to be 1/4 because the bearing is 7mm thick... almost 1/4 inch... so if I make the bearing thicker (2.5mm) to be exact, I'll end up with the 3/8 tenon that I really wanted. The downside is that the 1/8" comes from somewhere and I'll lose a little profile, but overall, I think this will work and give me the strong tenons that I want. 

Safety-wise, I think that there's enough threaded shaft to securely lock down the 9/16" rabbet cutter with an extra 2.5mm of shims sandwiched in there. The shims are .5mm spring steel 


I'll report back once I try out the new set-up

--edit--
Will note that there is a 9mm thick 608 bearing, but it's a specialty $95 bearing. 50 shims cost about $9, so I'll take the chance. I also ordered a replacement 608, in case I hork it up.


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## Tom King (Nov 22, 2013)

I had Whiteside custom make bits for a window project that you can see on my Windows page. One is a cope cutter that only cuts the little cutout under the shoulder. They can make anything you want, to either a drawing or match old molding. Cost is typically 225 to 300 per bit. They cut amazingly cleanly.


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## RepairmanJack (Aug 4, 2013)

Tom King said:


> I had Whiteside custom make bits for a window project that you can see on my Windows page. One is a cope cutter that only cuts the little cutout under the shoulder. They can make anything you want, to either a drawing or match old molding. Cost is typically 225 to 300 per bit. They cut amazingly cleanly.



Good to know of a source. Unfortunately, for that kind of money, I might as well just get a shaper set. 

I have made a couple more casement sashes, and decided to just "deal" with the 1/4 cut tenon. I found an acceptable solution by gluing up and 1/8" cheek for the tenon. This gets me up to the thickness I want. 

'though, I'm still having a little trouble getting the profiles to match.


For the moment, I'm working on a complete Shop re-alignment, including a new workbench, and tool arrangement to support my next set of sashes.


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## Tom King (Nov 22, 2013)

I'd modify the bit, cut the profile with one setup, and those through mortises and tenons with a tenoning attachment on the table saw. The only bits I'll buy, almost ever, are Whiteside. Not only will they make a perfect custom cutter, but they can modify a stock one to your drawing pretty reasonably.


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