I was a little late with this topic, I beg your pardon. But since I promised to share my experience, I must keep my word.
This topic is intended more for beginners, but I think that it will be interesting for veterans too.
I have a typical drilling machine in my room dedicated to the workshop. This is a Chinese-made machine with a power of 400 W and a speed range of 500 - 2150 rpm. It is better to choose a machine with a lower limit of 200 - 250 revolutions. But for this money, this was not found. It cost somewhere between $ 130 - $ 150. It is imperative to choose a drilling machine with a thick support stand. The column diameter must be at least 60 mm. Otherwise, the rigidity of the machine structure will be insufficient to perform the necessary operations.
Photo 1 Drilling machine.
For the machine, you will need to buy a two-coordinate vise with a material capture width of at least 100 mm. I have a Wilson brand vise. The brand is American, but everything is done again in China. And it's done pretty badly. Buying such a vise will greatly simplify the task of drilling holes in the briar, as it will turn your drilling machine into a two-axis milling machine. The vise fixing holes do not line up with the fixing holes on the moving plate, but the plate is made of cast iron and drilling is quite easy, you just need to correctly mark the place where the vise will be installed.
Photo 2 Two-coordinate vise.
The machine must be rigidly fixed on the work table, for this, as a rule, there are all the necessary holes at the base of the machine.
The first thing you need to do after assembling the machine and installing two coordinate vices on it is to check that the vise is perpendicular to the drill.
You need to take a drill at least 200 mm long. Turning on the machine at the lowest speed, check the drill for radial runout, it should be absent. And if there is no radial runout of the drill, then you can proceed to the next stage.
Place a square on the vise jaws, and check how your drill is set against the vise jaws. In two planes.
Photo 3.
This photo shows that approximately at a length of 150 mm there is a deviation from parallelism by about 1 - 1.5 mm. This will practically not affect the accuracy of hole drilling. In this direction, you cannot correct anything, since the machine usually does not provide adjustments here. You can try placing a thin plate under one of the edges of the vise and try to align them with the drill. I also need to try to do this, as my hands have not yet reached this work.
Photo 4
In the second plane, there are no deviations from parallelism between the drill and the square. If they are, then you can slightly turn the base plate of the drilling machine in the desired direction. This plane is more important for accuracy and therefore non-parallelism is not allowed here.
Let's move on to drilling holes.
The next step is to mark the briar block.
I prefer to work with the shapes of the pipe drawn on paper. I just glue the paper with all the drilling directions I need to the block. It's more convenient and easier for me than drawing lines on the briar.
Photo 5 Briar Block
Here you see a briar block with the side edges of the blocks already milled to full parallelism.
Photo 6
Photo 7
The two-axis vise provides very high surface accuracy and high parallelism of the side edges of the block. As you can see here the non-parallelism does not exceed 0.1 mm.
Having a vise-coordinate vise is quite simple to mill, you just need to rotate the knobs that move the block in the direction you need. I forbid you to milling anything other than wood on a drilling machine. The drilling machine is not intended for milling at all, you can only mill wood at a time, removing a layer of no more than 3 - 4 mm. You can use a conventional end mill at maximum RPM. The feed speed of the workpiece should be small, there is no need to rush, otherwise you will kill yourself in the literal sense of the word. This is a rather dangerous type of work. If you have enough money, it is better to install a collet for the cutter instead of the drill chuck. It will be more reliable.
You do not need to mill the edges of the block for complete parallelism, this is not an obligatory part of the work, but then you should completely clearly understand what the base surface is and how to work with it.
The vise has two jaws. One mobile one stationary.
The base plane of the briar block should always be pressed against the stationary sponge, and the one where you have a piece of paper or drawing is facing towards the movable sponge.
When clamping the workpiece in a vise, you must make sure that the reference plane is firmly pressed against the jaw and there are no gaps.
I always start drilling holes in a block by drilling a hole for the smoke channel.
Clamp the block in a vice.
Photo 8 Block in a vice.
Make sure that the axis of the smoke duct opening is perpendicular to the vise jaws.
Photo 9.
Cut a rather large piece of briar above the smoke channel with a hacksaw and gently mill the rest
Photo 10
Next, using a vernier caliper and a square, without removing the block from the vice, draw a marking for drilling a hole for the smoke channel
Photo 11 Hole marking
Photo 12. Vernier caliper.
Then, using the handles on the two-coordinate vise, it is very easy to set the workpiece exactly in the center of the drill. do this and drill a hole.
Photo 13 Hole ready
In the first part, everything. Tomorrow I will try to write the second part
If something in terms is not entirely clear to you, ask I will try to explain better.
Best regards Odissey