Master 175 Cutaway

[Robotnik]

My son's been under the weather & correspondingly beside himself, so during the times my wife had him today, I ducked out to the garage to relax. Made this Master 175 cutaway; love how it turned out.

From the wear on the fork, you can tell I've used this particular lock approximately 47,000 times for bypass practice before turning it into a cutaway .

[Gantry]

A very clean cut-a-way, looks nice! Great job.

[jimu57]

Now THAT is cool!

[dontlook]

That looks amazing.

I have some many questions as I have done a lot of work on 175 making a cutaway.

Did you use a mill to cut it?
Did you separate the housing from the body to do the cutting?
Did you do anything to clamp it in place special? I found it would shift if too loose but, if too tight would malform.

Was it just parallels you used for the setup?

It looks kind of like maybe it was a 3/8in end mill? Carbide w/ AlTin coating?

[Robotnik]

Did the whole thing with a drill, die grinder, and metal files. Drilled out the shackle retainer & popped out the mechanism, used a cutoff wheel to carefully rough in the cutaway portions, then finished with a mill file for a smooth finish.

Alternated holding it with either a bench vise or secured to bench with vise grip clamps. I did precision metal fab prior to a career-ending back injury, so it felt good to do something like this again. Appreciate the kind words.

[dontlook]

What does the other side look like?

Maybe practice is the only answer, but I try to drill out a whole opposite the pin to pop it out with an arbor press. I find on the drill press the bit moves around a little to one side or another when it comes down and trying to get started(I do use a punch to make a divot). Any advice for correcting that? Or just starting better?

Here is a picture of my cutaway. I'm an amatuer with maybe 50-75 hours on the mill at this point.

[Robotnik]

Nice; I like the full exposure of the fork. If I ever do another one of these, I'll definitely machine out the top of the case more thoroughly like you've done here.

As for the shackle retainer, I drilled out the steel insert over the pin (center punched & hand-drilled starting with 1/16" & stepping up from there). Worked for me here, but if I was even a little bit off I could see this method being disastrous.

[Robotnik]

Here's the back side; basically just flipped the pin around (pulled pin by drilling into it after drilling out insert), and hammered it back in.

[dontlook]

Hmmm thanks for the info on getting it started!

I have been doing a lot with this lock and explaining it to many people, so I wanted to expose as much as possible. If I do more I was thinking about tightening up by the area by the fork and going a bit deeper it is hard to see the pawls/locking dogs(which term correct?).


The hardest part is to the right of the last wheel I cut a window without removing all of the metal next to the dial. I wanted the so that folks could see the flat and gate, then practice with the feel of the bottom cover there.


I'm not sure I understand about the pin. I thought the pin to be one piece, but it sounds like you are indicating it is an insert and a pin?

[Robotnik]

Regarding the pin, there have been several generations of 175s (with varying materials & of varying quality), so I don't know that there's a clear, across-the-board answer. This particular one, I was drilling, drilling, drilling as if in hardened steel, then I broke through what seemed like a cap (my bit pulled it off upon breaking through). That left an exposed pin, I drilled into it easily with a 1/16" bit, which brought it out enough to remove with needlenose pliers.

That said, I definitely have one or two that look different, so some may be one piece.

[dontlook]

Thanks!

I put one of the wrong pictures above. This is a picture of the pawls.

[Mudman]

Cool! I love seeing cutaway's of things.

[ppipowerclass]

I have seen a LOT of 175 cut aways.. And that is by far the cleanest one I have ever seen. Very nicely done.