G'day again,
Seems we are on our way!
I think to do this right there will need to be a few sub-sections to this forum, one for how-to's with regards to making actual parts (tutorials), and another that discusses the machines and their use themselves.
The one for the actual making of parts is pretty obvious in what it would include (tutorials on how to make a brake rotor, gear knob, shock absorbers, exhausts / mufflers etc - I know mikemechanic has already run off a few sets of mufflers, maybe he could write a how-to?), whereas as a decision needs to be made on how involved the machining sub forum would be. Yes I know this is getting pretty involed, but you know at some stage speople are going to ask questions like, do I need cutting fluid, what is the best to use, one has already appeared about the best tool bits to use.
I think it would be of benefit to start of with a basics of use section (the do's and dont's of a machine tool - milling machine and lathe), then more specific discussion on machines and how to machine various metals, speeds and feeds information, cutting fluid, how to drill small holes without breaking the bit, technical type questions for those that just want to know. Also an area for machine hints and tips (this could even be brand specific) could be beneficial, however there is already a large amount of information on the web for this. I also think a links page would be of enormous value. I know it is not really the done thing to include links to another site from a forum, however in this case if the links were moderated it would certainly save starting a lot of unneccessary threads / posts..(I see one of my references to a particular mini lathe site has already been removed from this very thread - shame, it is probably the best resource of information for small machine tools the web has to offer!).
There are far more experienced machinists out there than me, I'm more of a 'if it works do it' kinda guy, but I am happy to offer any assistance to anyone if I can help.
I mostly use my lathe for production work, I converted it to CNC, so it is actually more of a pain to make one part than it is to do 10! I'm sure I have done mods to my lathe that the designers of the thing would shake their heads at but it works for me.
A few little tips I've learned along the way...
I almost exclusively use indexable carbide replaceable tips in my cutters, with the exception of HSS tools which I will grind for a specific purpose if required. Yes, they can cost a bit more to start with, but you get very long life out of a cutter, and you can rotate the tip (3 times) as one cutting point starts to dull, again though I use for production work so the cost is justified for me.
When parting off the trick is a slow speed and a faster feed of the parting blade. The sound should resemble that of frying bacon! When I am parting off anything over about an inch diameter (25mm), I will use a cutting fluid. It is also important to ensure the cutting / parting blade is ground correctly or it will stall the lathe.
To those who are using the parting blade that comes with a standard set of carbide brazed tools (for memory it is about 3mm wide!), if the finance allow, I highly recommend buying a proper parting blade (around 2mm wide), and the correct holder, this will put a lot less stress on your machine and reduce chatter due to less surface area contact, and save wasteage of the material. You will be amazed at the difference 1mm can make.
I have used a number of things for cutting fluid (even actual cutting fluid!!), but in true backyard workshop style, I get very good results from automatic transmission fluid!
I always use cutting fluid when drilling a hole (it prevents the 'scarring' inside the hole from the drill bit).
When drilling a blind hole (very deep), I advance the drill bit around 2.5 to 3 times the diameter of the drill bit, then bring it back out to remove the chips, douse it in fluid and go in again, this prevents a lot of bit breakages, keeps the bits sharper for longer, and prevents the actual chips themselves accumulating on the bit and scoring the hole even larger.
There is no real simple way to polish an alloy part if you want good results (ie: no machining marks). The process is similar to what you do on a model car body. My steps for aluminium are:
Sand with 1000 grit, then 1500 grit, then 2000 grit paper (I cut it up into squares about twice the size of a postage stamp), however, I use the paper 'wet' (have it sitting in a container of transmission fluid), once done, thoroughly clean and wash the part under water as the fluid will make the piece develop an almost waxy / greasy-like coating, once done, put back in the lathe and finish off with Autosol on a cotton cloth. You will get an awesome shine.
Sorry for the long post.
I hope this helps a few. Happy to provide other info where I can.
Moderators feel free to move any of this info where you guys see fit.
Have fun.
