LumberJocks

portable handheld mortising jig "build blog" #8: begining to machine the stop blocks with procedural steps to make one part

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Blog entry by hobby1 posted 10-28-2013 04:23 AM 854 reads 0 times favorited 2 comments Add to Favorites Watch
« Part 7: finalizing front fence and start on clamping system Part 8 of portable handheld mortising jig "build blog" series Part 9: few hours this week, making the mortise length stop blocks. »

I needed to make a latching stop block to keep the router from slipping off the back, its not only a stop block, but also a latching block, because later I will attach some sort of a latchng mechanism, on this block to keep the router elevated above the workpiece while repositioning the router for the next mortise.

Started out with a quick sketch with some dimensions that later got changed during the machining process.

I also worked on making an arrangement for a “Y” axis stop, to set the depth of cut for a mortise, this feature is already built into every router base, by simple adjustments, however, depending on how long my mortise cutter will be, determines the amount of router base adjustment I can make, if I need more adjustment, then I need to make this depth adjustment feature, as well.
So I started out by making a slot to allow the sliding fit of a 10-32 screw and washer to fit into, for tightening down the stop block.

and to accomodate the washer now

now I want to start working on “X” axis stop blocks, these will be needed to set the length of a mortis to be cut.

again these a quick conceptual sketches, the dimensions get refined as I start the machining process.

two 1/4” dia. steel rods. to be machined with 8-32 TPI, to be assembled to the base of the unit.

and the machining process

and now drill and tap the base

and the assembly, these will later be cut to a shorter length, after determining where the stops will go.

now this weekend I have left off with the beginning of making the side stops.

here is the process to make one stop.
I’m showing the sequence of what’s involved to make a part, for the enjoyment of seeing how it’s done.
I will say there are numerous ways to tackle a job, it depends on the tools at hand, and the techniques learned through out the course of time.
For me personally this is the way I chose to do this job, here it is step by step:

Again I like to start out by first making a quick sketch, of what I’m envisioning, as I machine the part the dimensions get more refined, as I see needed.

now I mark out rough locations on the work piece this part will go at, by doing this I can determine the size of stock I need to aquire the right dimensions.

Ive determined that a 5/8” dia roundbar will work for this, at around 3” long, for a rough start.

now I need to square up both ends on both pieces, in the lathe, commonly refered to as facing off the ends.

now I start to get more refined in where to machine this part, by placing it in its location on the workpiece.

Now here is where some preliminary thinking comes into play, I need to machine a end rabbet, on the part, but on this opposite end

I need to drill two perpendicular holes, as well as some slotting, so this means both ends of this workpiece, will have machining operations done on it, Now I could use a vise, or “vee” block or any kind of appropriate fixture to be able to reach both ends in one setting, however, I have a nice tooling fixture called a “indexer”, better known as a “spin Jig”,which indexes every one degree for a total of 360 deg. because I’m going to be machining areas on this part 90 deg. to eachother, I opted to use my spin jig. That’s why I chose round bar for making this part, because my collets for this jig hold only round bar.

The next process is to set up this fixture, in order to set up any fixture, to the table it needs to be squared up with the axis movement of the table, therefore I use my dial test indicator to “zero” out the fixture, by first putting in the workpiece, and taking the readings off of it, to adjust the fisture to the table, to be square..

Now I start refining the cut lines,
such as the length of cut

as well as marking off the depth of cut

now back to the machining process as can be seen I need to machine this end,

but if I start machining this end imediately, I run into trouble trying to line it up back in the index jig, when I turn the piece end for end, because the other end needs to be machined in reference to this end, to line up properly on the project.

This is why I have this workpiece extended out as far as I can, because I need to machine a flat reference surface as far down this workpiece to where when I flip it end for end, I can use this flat end to set up as reference, but more on that later, so now to put this procedure in order, I want to machine this reference surface,

however if I machine a flat at the other side of the rabbet cut

, I risk making the end to thin after the rabbet is cut, so I need to make the flat refernce cut 90 deg. of this rabbet cut on this side,

.

because most of this material will be cutaway with the rabbet anyhow, not affecting the thickness of the rabbeted edge

With that in mind a first set the jig to read zero on its dial.

now I dial it 90 deg. to the left of zero, which is 270 deg.

now the workpiece is oriented 90 deg. from its original orientation when it was marked horizontally.

now using my magnifier, I line up the center of the spindle to the center of the work, and lock the “Y” axis table movement.

and now the reference flats are machined to around 30 thou. depth on opposite sides.

now I can move the workpiece insede the jig to make it more stable,and have a better grip on it when it comes to machining the rabbet, this can now be accomplished with perfect accuracy, by taking a precision square block and lining it up to the reference flat, and tightening the jig to rehold the workpiece, for the maching operations to follow.
This is the first purpose for the reference flat.

now that the rabbet has been formed on one end of both workpieces, I can now line them up to where they will be assembled to on the project, to start laying out the areas for drilling holes.

That’s where I left off this weekend, the next set of procedures to finish machining this workpiece will continue in the next installment.

have fun in the shop



2 comments so far

View stefang's profile

stefang

13530 posts in 2056 days


#1 posted 10-28-2013 10:01 AM

Still enjoying this detailed blog very much. It seems to me that a background in machining would sure be a big advantage for any woodworker.

-- Mike, an American living in Norway.

View hobby1's profile

hobby1

291 posts in 1019 days


#2 posted 10-29-2013 10:39 PM

Hi Mike, glad your enjoying the build blog.

Yeh, I think machining and woodworking go hand in hand, as they both require fixturing and setups, to accomplish the removal of material off of stock, and sometimes elaborate fixturing for assembly of complex components.

Plus with machining, you have the advantage to make tooling for woodworking, that is not affordable, or available otherwise.

Example, I needed a mandrel, to put on my big woodworking lathe, to hold a small wheel, to put a edge on it that was too small for a router, setup.
The wood lathe has a 1MT through its spindle, so by using my metal lathe and a shopmade tapering jig, I was able to make a 1MT mandrel to make this work for my wood lathe.

I find homeshop machining a great asset, when it comes to make tooling for all hobbies.

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