General Question:
I just recently fired up my el cheapo milling machine. Immediately, I realized that I need a few tools / accessories that I don't have. For instance, I need a much better lighting solution, something to hold a few key tools, better rulers, etc. This got me wondering, what are some other must-have tools to aid me in running a milling machine?


More-Specific Question
My first milling project was to cut down a free-float handguard. This handguard is a quad rail design with an A2 sight post cutout, only the cutout is in the wrong spot, as it sits about an inch too far forward. So, to make it work I decided to shave about an inch off the back side (the end closest to the receiver) which entailed removing the inch worth of material just mentioned and cutting new countersunk screw holes for the mounting hardware.

I was able to pull it off, but I had a heck of a time getting everything centered correctly. It was an awkward shape to measure the center point on, so I ended up using a metal ruler and eyeballed it to the best of my ability. It took forever and was just barely accurate enough to work. What tools do people use to find the center point on objects?

I found this thing: Center point laser doodad.

That would have done exactly what I was trying to do. I could have simply put my handguard in my vice, plugged that laser into the spindle, and then gotten close enough for what I was trying to accomplish / much closer than what I actually achieved. But I'd hate to blow $170 on something that there is an old-fashion trick or $10 dollar to accomplish the same goal.

Mechanical edge finder

Eta: mechanical edge finders I guess they're called.

PEC ROUND BAR CENTER FINDER TYPE WIGGLER

Not as accurate as some methods but it works for many non-critical projects and it's cheap.

Ah, I see. That could work. Thank you.

Forgive me if I'm mistaken, but I was under the impression I can't use one of those given that I have a manual lathe. Don't you need an electrically actuated X/Y controller to use one of those mechanical edge finders?

Buy this one. The 0.5" end is better when finding the edge of a part. When the head kicks over you stop and raise the edge finder and crank over half the diameter. You now know where the edge is. Half the width of your part puts you on center.  

My DRO has a half function so I can hit both sides and punch the 1/2 function and crank to zero.

https://www.ebay.com/itm/224299783302

Go watch a YouTube video on edge finders.


You did say you had a mill and not a lathe so I'm assuming you do intact have a mill.

Once you establish center you do not move that axis until you are done with that feature. Use your table locks.

Rulers ?
LoLoL...

I suggest better knowledge, like taking a night course in basic machining.

And I hate to ask, just what milling machine do you have ?

Sorry, I don't know where the word "lathe" came from. I have a milling machine. Brain fart.

Thinking out loud, I suppose I could use a mechanical edge finder by running up to the side of the piece, find the edge, make a note of position, do the same to the other side of the piece, and then halve that to find my center point. Is that essentially what you described?

I'm dicking around in my garage, not working on the Manhattan Project.

If your mill has a dro it should work fine, otherwise you have to compensate for the lash in the screws.

What you can do is measure the part with at least a caliper, micrometer preferred.  Use the edge finder to find one edge.  Move to half the part width plus half the edge finder tip.  Usually either .100 or .250 depending on the edge finder.

Unfortunately, mine does not have a digital read out, and I have a lot of lash. I appreciate the explanation. I will give that a shot.

No. Backlash will ruin your measurement. Just measure the thickness with calipers and move half the distance. Only move in the same direction.

Get a Noga mag base indicator holder and a good dial test indicator. One of my most used tools in the shop and extremely versatile.

This will get you centered on your parts more accurately than any other method on a manual machine.

To the point of the problem you said you faced, Stefan Gotteswinter on youtube just did a video on different ways of edge finding that might be worth you time to look at.

In general I got alot from watching youtube machinists. I could see the tools they used and kind of reference what I wanted for stuff I wanted to do. It doesn't have to be fancy stuff either, some of them will show simple, poor-man ways to accomplish things. Off the top of my head there's:
This Old Tony
Stefan Gotteswinter
Tom Lipton (Ox Tools)
Joe Piezynski
Abom79

But I would say some of the first things I bought and would tell someone to get are:
Dial indicator w/mag base
Dial test indicator and something to allow you to mount it to the spindle
Parallels
Dial calipers and/or micrometers
123 blocks
V-blocks

I don't know what you have already.
I'm going to go with you already have a vice and at least one endmill with a collet to put it in.

Full disclosure, I'm just an casual hobbyist, not a pro. I just have a lathe and a mill that I dick around with when I have an idea to make.

I'll give that a shot. Thanks.

Thank you. I'll check out those YouTube videos.

I currently have various end mills and collets, 123 blocks, a vice, a set of parallels, some countersink bits, and a few other things I'm probably forgetting. I do not have a dial indicator or a micrometer. Thanks again for the input.

No offense intended, you're very ignorant of machining, we can tell from your posts. You may opt not to take an evening class (that would be the best, fastest, and also most expensive way to become less ignorant), but you definitely need some education or you're going to face a steep learning curve of messed up parts.

The above mentioned posters on youtube are very valuable! Thousands of hours of youtube videos to watch...

True....I bought a Bridgeport mill and Southbend lathe from a local tool & die company that was shutting down.  I had some basic experience with both, but well short of being considered a machinist.

The amount of stuff I learned from those YouTube channels really helped me learn.  The other thing is don't start learning on projects you care about screwing up....take some scrap metal and do the steps on it that you'll have to do on your real project.  (find the center of the part, mill a 1/4" slot that is 3/16" deep...etc)  Check your work with legit measuring tools, micrometers / calipers...etc.

I'm assuming you have one of the cheaper benchtop mills (Harbor Freight / Sieg X2)....I started with one of those.  If you know what you're doing and take your time, you can make good parts with them.  I milled a number of 80% lowers with one.  You have to know the limits of the machine, like how deep of a pass can you take in aluminum without having chatter and stay within those limits.  You learn those limits by messing around with scrap metal like I mentioned above.  Turn your scrap metal into different scrap metal and learn your machine....your skills will only grow with practice.

Blondiehacks has lots of decent beginner videos and the OP is really, really green. He can definitely benefit from several hours of YouTube.

Really, you can tell from my posts where I essentially said, "Hey, guys, I don't know what I'm doing" that I don't know what I'm doing? Have you thought about becoming a detective? :-)

You may be new to machining, but you have the smart-ass part nailed down.  lol

It's all just arithmetic and then a little trig.  Best way to learn simple machining is, IMO, to sketch it out.  Need a .307" wide slot, 0.150" deep from a .250" EM?  Draw it out, write down your steps, execute them.  Id start with a .250 slot right down the center, cutter depth not to exceed 0.5x tool diameter.  That's 5 or 7 passes depending on your layout.  3 to get within .010" of depth, then 1 or 2 per side at full depth to get your width.

As far as backlash, meh, it sucks but it must be overcome on all but the finest and newest of machines.  The only thing to know is that you need to approach from the same screw turn direction each time.  

Machining is really dead simple at this level- just go slow.  Plan out every move ahead of time.

Haha. Thanks for the feedback. I went back and added a smiley to better convey my “just busting chops” intent.

I plan to check out all the recommended YouTube videos. One issue I’ve run into is that a lot of the videos I’ve watched so far don’t seem applicable to my machine. Some cover universal concepts, but many of them concern machines with a electronic controls that don’t apply. In short, I’m making my way through YouTube, but it’s sort of hit or miss.

Post a pic of the machine, I'm 99% sure the collective can walk you through about anything on it.

Second this recommendation. She specifically has a playlist for "Mill Skills" that's a good jumpstart.

And regarding the comment about stuff not applying because you don't have "electronic controls". I'm assuming you're referring to a DRO. Anything you can do with a DRO can be done with the machine dials and some (ok, sometimes a lot of) math. The DRO sure makes it a lot easier, removes backlash worries, and helps prevent mistakes around things like losing count of rotations, but anything you see done with a DRO you can do without one, so don't let that dissuade you.