Going to write out something in the next week, a blog post of sorts. I want to do them often but time is of the essence and my writing takes a lot of grammar check… :-).
Most of you guys here are MEGA self study; most the machinist here have taught me something.
What would be a good topic to breach? I don’t know a lot but play with this stuff often.
I’ve done a full blog on deflection in V-slot. I believe it assisted in a V-slot deflection calculator on the awesome OpenBuilds resource page (one of the more amazing locations on the internet).
The most read blog is the “How to CNC” but it is still up, a number of them I take down.
Eric and I did a speeds and feeds chart, as well as explaining (with amazing graphics) chip load. This one is visited often. Do wish more would contribute.
On the topic, thought about running through tool changes, it can get deep quick though.
Bed leveling, what processes are actually handled by the controller, best way to square an R7, what’s the next product, difference between VFD driven and ESC driven spindles, dB readings on spindles, belt vs ACME vs ballscrew, should you go Mach3/4, LinuxCNC,… what makes you say hmmm?
So… if I write something up what would you guys like to argue with me about? Not sure I’ll know enough about all topics listed, but will give it heck, or link your write up.
Bed leveling and squaring an R7 makes me go hmmm.
My next project is sorting out all the ways I can use probing to make my software understand the hardware. I would love a jump start.
I am going with leveling & squaring, too…
Yeah, squaring and calibrating is a topic not often discussed in depth or detail with hobbyist machines. Most settle with “did it surface without looking ugly? Good enough.” Which even though we are hobbyists is just so untrue. So many issues come from being out of square or spindle out of plumb. There are many ways to do it, some lend themselves to some machines better than others. And some require more expensive equipment than others. Definitely a rich topic for discussion.
Some thoughts on tramming, if the machine cutting the plates is not square then the plates are not square. The R7 design keeps one set of holes without eccentrics making the system aligned as well as the mill that cut the plates. If we were to redesign the R7 to have all eccentrics then every cut would be suspect and tramming alignment would be part of everyday operation and I don’t think any of us signed up for that.
Another thought on cutting plates for the R7, the wheel bolts need to engage the nylon part of the locknut fully in order to stay in alignment. This can only be done with tight control over the counter sink depth.
On the plates I cut for mine I was too shallow on the countersinks and used longer fasteners. However, some of the clearances were too tight to use longer fasteners and locktite was required.
So squaring, leveling, tuning.
I like the squaring &leveling topic. You can cut many project without doing a lot but at some point you will need, no require, a square and level playing field. Then moving into relative accuracy. Many times you may not need to square a block for a given project. Maybe just a flat surface relative to the cuts made will keep you in alignment. Other projects require two faces squared and leveled., etc.
PCB milling requires a flat surface or a correction map to fix that but even that will not help if your material is not held flat. Lotsa land mines here and a good step-wise process would be good to work through.
I’ve been running through the squaring in my head all morning. The topic is kind of a land mine as Don points out.
Here’s why. My R7s make the plates. The tools I use to true a build are not the ones you guys will have laying around, well typically.
Magnetic based dial indicator, 600mm and 300mm calipers, starrett square and a machinist level.
There’s a $1000.00 of tools easy, would not expect these to be laying about typical shops.
A tape measure and speed square is simply not enough for our builds.
Spoiler board is also a really big deal, many guys here have a modified set up.
If I (we) do this it may be a good write up for here on G+.
Colin hit on some highlights of the plates, recess thickness, reference holes, etc are built in to the design to “cement” each axis. These are vital. Colin, at one design phase R5 I believe, the entire X Z was on eccentrics… it was a pain, but really allowed for some creative tuning.
I still often relate squaring the R7 to making a 12”x12” (v cutter) box. A good speed square can typically show an out of square and is also good for tuning steps/mm.
Tramming the Z can be a bit of a bug. The spindle wants to create a rolling moment on the X. Stationary, using a dial indicator on the face of the spindle works amazing, lot of travel length, hard to keep it perfect on the outer cylindrical face though. A measurement off the X axis face though can give some assistance but needs to be based off the Y axis not the spoiler board in my opinion.
There is a very slight play in the holes mounting the X to the Y, loosen bolts on both sides and square.
Spindle, I believe the best method is to fly cut the spoiler board with something big. I like the Amana tool 1-1/4”. Through this method I typically find things are good, if not I mess with the spindle clamps and remove the remaining Z/Y issues.
Thinking out loud here.
@Brandon_Satterfield Squaring/Leveling - I could get jiggy with that! I just spent a lot of time honing/truing my machine after I re-located my R7 2 weeks ago!
I think with a straight edge, a tape measure, a flat plate like a table saw and a 6” machinists square we can get x and y square to a really high accuracy. The Z axis is a harder problem.
@Brandon_Satterfield I just reread your original post and thought I would offer proof reading services if that would be helpful.
Hey Guys, sorry for the delayed response. Guess my notifications aren’t really, notifying.
The R7 manual is due for a revision. It currently resides as a redline. All you recent guys with limit switches know what I mean.
When the manual is revised we can do a addendum with squaring techniques.