The new Proxxon router attachment arrived and is a real improvement over the old dremel attachment.
As with some of the Proxxon attachments, it is best to do a quick disassemble, deburr and lubricate.
After that, it works very well. The spring loaded plunge with depth adjusting threaded guide is really nice and makes it much easier to set a more precise depth.
The larger flat area means you can reach out further on a flat plane to get a good, level cut.
Now, on to cutting.
Turns out that forming the halves of the main body out of one solid slab of Coosa makes things much easier in a few ways.
By pulling the CF over one continuous surface yields a much more uniform CF side finish that only needs a little bit of flat sanding to level off.
It is also very rigid with virtually no bend, so routing out areas is much easier.
Receiver Channel - Cutting out the receiver bedding void was done by first marking the depth of the channel on the inside face.
Note: The black vertical line is my main reference point that is set to the back of the receiver. This is what I take most all of the measurements from.
The top cut is made by marking the width of the channel from the centerline out to the edge of body’s top surface.
I try to measure everything from the centerline out to avoid minor measurement errors.
I then cut out the top layer of CF using a make-shift rip guide.
There is a bit of room for error as it will be filled by the bedding compound and sanded flat.
Then the final finish will be done into the last layer of CF.
Removing the arc of the channel was done with a drum sander that gives the relief needed for the receiver to fit in.
This initial radius was evened out later when the halves were put back together.
Set Screw Cut – I initially cut the channels for the set screws escutcheon fittings using a round burr to give a more radiused cut. However it became evident that it would have been much better to simply drill this area out with the halves together.
Cutting them out as channels was a waste of time because in doing it ‘free hand’, there was no way to be precise enough so when the halves are put back together, everything lines back up.
Not a big issue as it will all be filled in when the fittings are epoxied in, but still a bit of a pain.
In cutting out the main void for the action you have to make sure the flat bottom of the router is kept level with support from the face of the slab.
One way to do this is to cut out channels while leaving a bit to support the flat of the router attachment.
Pretty fun actually, so long as the vac is close at hand, otherwise it gets a bit gritty.
Eventually I left one ridge in the center of the void to be cut away last.
Halfway through it looks like big termites at work.
Lesson Learned - Without the ability to lock the piece onto an x/y milling table for really precise cuts, I find that leaving that bit of extra material on each internal edge makes it easy to touch up with a drum sander when the halves are together. It takes a bit of fine tuning the voids to make sure the action can be lifted out of the stock.
Since my plan is to bed both the receiver and the trigger guard with Marine Tex, the cutouts don’t have to be really close tolerance.
Of course the closer tolerance, the less bedding compound needed which saves a bit of weight.
Turns out that the fitting cutouts are all in pretty close proximity, so there is not much wasted space within the core of the main body.
That efficiency of space is good for keeping weight down, but it gets a bit tight in there for cutouts.
Since the internal threaded fittings will be set with micro-balloon filled resin, it should keep a bit of the weight down without losing bonding strength.
All this prep is where the real work is.
Also figuring out what the most efficient method for each step eats up a good amount of time.
Taking notes on measurements and making a pattern for the initial Coosa cutout will save time in the future.
Last cut out was for the stock tube section inset.
Initially setting the LOP to just under 13” to allow adequate space for the shoulder fitting.
Since it is adjustable, it is better to be a bit short than too long since it’s easy to add length with spacers.
Another added benefit is that it will allow for a much shorter LOP for a smaller person.
I set the depth for each cut out at half the width of the stock tubing and after tracing the outline of the tube, cut the void out.
Here is a little touch I thought I would try.
Since the escutcheon opening is right where the main arch of the mag well, I cut a long section of brass tubing to act as a liner.
Once it is set in place, I will cut it off just a bit proud of the surface.
That way when the final layer of CF is applied, the interior of the tube will be leveled with clay to keep the excess out.
Once cured, it can be filed away for a nice flush fit – at least that’s the plan.
It can then be polished as a nice accent or darkened to a patina.
The parts are actually starting to look like something resembling a rifle stock.
Now I’m going to have to think a bit about the best sequence to set everything together.
Also need to do a bit more prep work on the stock tubing section prior to setting it in place.
Sorry if the explanations got a bit confusing. Not being a machinist, I don’t know all the right terminology and am just trying to be descriptive.