Question for Machinists!?

[DiverRay]

But Dan,
Can you machine the titanium? and what will you use it for?

Ray

[xswilly]

where i work we use an item we call it jig plate
its aluminum and its 1" thick, we get it in any size we ask for
normally we get 11" x 13" x 1" at a cost of 30 to 40 dollars

it comes in machined on both sides
we get it from a place called jorgensen metals

your price seems way off
maybe they have a minamum order

[mainlylinux]

I don't know what I'd use it for, possibly a replacement for gold at that price :-)

Actually everyone who is interested in this thread, check this out. Scroll down a ways to see the V-12 that he built. If you click the pictures they'll zoom in.

I can't believe one guy did that. I wish I had 1/99th that guys skill.

Dan

Originally posted by DiverRay
But Dan,
Can you machine the titanium? and what will you use it for?

Ray

[mainlylinux]

Ok, holy %$@*!

I was on the sherline CNC site and there's a guy who built a supercharger (yes, from scratch) for his Honda 50cc trail bike. wow.

web site link








wow.

[Dennyz]

I have a Bridgeport mill (J-Head). My dad and I picked it up at a school auction for $1500. We spend another $1500 rebuilding it. A year ago, I fitted it with 3 axis CNC for another $1500.

I built the complete CNC system from eBay and McMaster-Carr. I did purchase Gecko drivers (worth the $$). I built my powersupplies from step up/down transformers (eBay), I purchase surplus servo motors (eBay) and fabricated my mounting brakets. I control it from a 400 MHz Pentium PC running TurboCNC (share ware).

I didn't really know what I was doing when I started, but thanks to a lot of information on the Internet and from hobbiests, I am very pleased with the end result.

Next is a servo controlled rotary table (4th axis).

[mainlylinux]

That's awesome. I'd like to take classes at a high school or something to learn about operating mills and lathes. I took classes in high school but I don't remember a whole lot...

Dan

[Dennyz]

Speaking of School!

I stumbled into the best job I could possible have (for my age). I teach electronic in a Robotics and Manufacturing Engineering program at a high school level vocational school. I co-instruct the program with a 30yr machinest. The class has 3 CNC mills, including a Hause. We are getting a 3D printer this fall.

I help him with his electronic projects and he helps with with my milling projects. I just recieved a personal copy of MasterCAM (about $5k). I have died and gone to heaven.

Plus, I have August off! I teach a 26 day summer program in July.

[TopCatGr58]

Problems with Rotary Table?

Hey all,

Well, I spent this afternoon "trying" to take my Rotary Table apart to try to lubricate it!?

I did find out that it is a YANTAI Machine Tool Accessory, from CHINA, model # TSL200 that I got from EBAY! I was able to figure out the locks, and engagement mechanisms for the worm gear assembly! I can get the table to rotate WITHOUT The engagement of the worm gear crank, but when I turn the assembly and engage the worm gear, the crank is extremely difficult to turn. It has this little handle on it like on my LATHE Cross slide, and I would think that it should turn easily enough to rotate the table WITHOUT causing the table housing to lift up or turn!!

I found the Yantai website, and a few distributors for their products, here's a photo:


I pulled the handle off, there is a keyslotted shaft, it appears to be held in with this 4 notched nut type thing, but the nut spins with the shaft. I have tried spritzing it with PJ Blaster, it got slightly easier to turn, but not much, still have to two hand it!

Wonder if I should take it to a machine shop, perhaps they might have a large CLEANING bath that they could immerse it in and soak it to penetrate into it to degum? the old grease and such. They might also know how to get the worm gear assembly out to recondition it? Wonder how much this will cost....thought I could save some $$ Ebaying it vs. NEW?? Sometimes you win, sometimes you loose!
T.C.

[vanhump]

TC I worked at the Newport News Shipyard at one time and at some tool and die shops around Richmond. There are a lot of used machine dealers in that area and in the Roanoke area and most are usually pretty resonable. A lot of attachments that have been used around shops and coolant has been allowed to dry up in them will lock up pretty tight and about all you can do is wrestle them apart and clean them. most of the time soaking them does not do a lot of good as the cleaner wont penetrate enough to cut the crude out until you get them apart. Also look up J&L Tool. They have losts of machines and attachments and most are resonable priced althouh they do handle some junk.

[TopCatGr58]

Success!

Hey VanHump,

Thanks for the info. I contacted the sales reps in the US requesting an exploded view/owners manual for the table. They actually sent me a PDF one, so I was finally able to figure out how to take it apart. Once I got it apart, there wasn't any corrosion or rust between the bearing type surfaces of the worm gear shaft, both near the handle/crank as well as near the worm gear end!?!? The shaft didn't appear to be bent?

I first tried buffing it with some emory cloth both on the shaft as well as inside the eccentric shaft housing, but it just didn't make it loose enough. SO....I said, I've got a lathe, and put it in my chuck and shaved off a thousandth or two, and it then fit nicely, no slop, but spun nice and easily! Put it all back together and greased it up, and now the table turns with EASE!!

I have done a test run with it, and it is so nice to be able to mill out perfect circles in the plates!!! The other problem I encountered is that the Rotary Table is twice as wide as my cross slide table! So... I rigged up a bracket that I mounted to the base of the table, and then bolted to my tailstock to secure the other end of the R.Table. This way I can unlock the tailstock, slide the table left or right, lock it down and then cut another path out of the plate easy as pie!!!

This was about the last piece to the process of me getting things in order to be able to start producing my S.O.F.A.'s.
I'm still working on some clamps to hold the workpiece down on the R. Table, but they are fairly simple. I've got some photos, but I'll post them tomorrow along with the end result of a finished plate! It's nice to be on vacation to have time to play with this stuff!! I may like whittlin' metal afterall!
T.C.

[TopCatGr58]

Wearing out mill bits too fast?

Well,

I've been able to crank out 6 plates since getting all the machining tools and such in order! But, to my surprise, I've already dulled 2 of my 1/2" 2 flute carbide end mill bits that Bruce Gerkin sent to me (thankyou again verymuch). I've also learned that my simple angle grinder discs and even my AL-Ox grinding discs on my bench grinder have essentially no affect on these things! I found out that I could actually use them for Re-dressing my grinding wheels!

So...I realize I would need some diamond grinding discs to be able to touch these things. I can get a set of 12 diamond encrusted discs for my Dremmel, would I be able to put an edge back on these things? I've learned how to grind my own lathe cutting/turning tool bits from HSS, but these bits are a bit more complicated!

I'm also curious as to how these bits got dulled so fast. I'm using the slowest milling speed, and I'm not advancing the material fast at all. I'm also taking only about 0.10" worth with each pass. Remember I'm milling T-6061 aluminum. Should I be using Carbide, or HSS? I read in the Little Machine Shop website that because I'm working with Aluminum and turning at slower speeds with my smaller lathe/mill that HSS should provide better smoother finishes than carbide!?

Any pointers or explanations about the different materials for mill bits?
T.C.

[pathfinder]

Hey TC, Aluminum demands a higher speed than you are currently running. Step it up a notch or two, normally as fast as the machine will go. Are your carbide endmills ground for aluminum? They have a bigger flute area to alow for the bigger chips. Fast-spiral end mills are used when machining relatively soft materials that will get hot easily. The design of this end mill allows for fast removal of the chip and reduces heat transfer to the work piece. Fast-spiral end mills are also called high-spiral end mills.

Standard two flute are ground for steel. Check this out for pic of Aluminum cutting endmill.



This tool is made to cut steel


I know they look alot alike but the aluminum cutting endmill has Higher helix (Fast Spiral) and a better finish to cut your material.

What the above means is that your 1/2" endmill rpm even at 1000 RPM is still way to slow @131. The way you arrive at that is simple.

SFM=.262 X RPM X Dia. Your 1/2" mill works out to only be running 131 SFM which is not even half of whats recomended. That is if your running 1000 RPM, which you are not. To run the correct SFM you would have to be running almost 2300 RPM

What I'm saying is get your machine running as fast as it will go and get some High speed steel endmills. Your machine won't go fast enough to run carbide correctly.

Your feed rate should be .0005 thru .0015 per tooth.

A common mistake made by even experienced machinests is if they have a problem they slow down. NOT.

[xswilly]

hey TC
you are prob running your rpm too slow
and I bet if you look closely at your carbide encmills that there is a build up of aluminun on the edges, which causes the endmill to appear dull
if that is the case you can scrape the aluminum off of the cutting edge with a sharping stone or I use a penny, because of it being a soft steel and won't dull the endmill.

if your endmill is indeed dull, then you will need to sharpen it.
but that does require diamond wheels, and a special fixture.
no way can you do it on a bench grinder by hand

[TopCatGr58]

Hey Path and Willy,

Thanks for the info. I could have sworn that I had read a SFM rate of 200 SFM for aluminum, but that may have been LATHE speeds, not milling speeds...If there's a difference!? I read it in an FAQ on LittleMachineShop site IIRC!?

My lathe is set at 500 rpm=slowest, with my 5.25" diameter log, it's almost 700 SFM rate at the widest part, but decreases of course as I move towards the center of the piece during facing/turning!

You are both right, I'm running at only 430 rpm Mill spindle speed, but can go up to 1500! I am getting some fair amount of heat transfer to the workpiece, and scurf buildup on the bits!
Willy, I got your PM, and will take you up on your offer, thankyou!!

Is Carbide the type of bit I should be using, or should I use HSS for the future, since I should be able to regrind the ends of the HSS myself?? I'm trying to learn!
T.C.

[gerkenbruce]

HI T.C
just send them back and I will sharpen them on a cuter grinder .Your going to slow like path and willy said are you sure there dull they will load up when running to slow and look dull?

I took my CNC,s all a part after they stood in 5 feet of water total rebulid new bearings took the motors a part and bake them what a mess will have them back on line soon . we are working 12 hrs a day untill were back making missel parts.

XSively
Bruce