Monday, February 28, 2011

Tang Kee Milling Stainless Steel 304

My new friend, whom I found having the same hobby and machineries, sent me this video.  He was cutting stainless steel to make a tool changer (this guy is way ahead of me).  He is feeding at 800mm/min with spindle at 2800rpm (max on stock pulley) and depth of cut (DOC) of 0.05mm per pass.  This is really impressive!!!  Wonder why I'me having so many problem in milling mild steel...

video

Sunday, February 27, 2011

Flycutter: milling the angled face

This was the setup I started with on Friday night:

Using Taig's ER16 to 3/4-16 adapter on the adjustable angle plate

Dean Williams and the guys from Sherline group are right.  This setup is too spindly.  The vibration and noise during cut was unbearable.  I stopped the gcode after a couple of passes to see if I can improve things a little.  The vise came to mind.

I hold the shank of the steel blank in the slot of the screwless vise and mount the vise on the adjustable angle plate.  This felt much more solid that using the ER16 adapter but I'm still in doubt: will the angle plate cause problem?




I started milling away with an 8mm endmill.  Feed was set very low at 60mm/min with spindle at around 500 rpm.  0.1mm was taken off each pass.  This took me almost 2 hours to mill away only 2mm worth of steel.  Painfully slow.  The vibration was still there and the spindle seemed to lift up every now and then.  Rigidity issue?  Time to upgrade to the Monster Mill Column?  I don't know.  I'm tempted.

Anyway, got the job done.  Surface finish sucks.  Some work needed later to improve its look.



One thing I found that put a smile on my face; the adjustable angle plate is quite accurate.



Now I'm left with the 2 slots.  One for the left hand tool and the other for the setscrews.  At this stage, I dread thinking of having to do the slots after what I've just been through.  There must be a solution to the problem encounted while milling steel.  I believe the sherline is capable enough to do the job easily.

If anyone knows of how I can do this better (milling steel on a little machine), please please please, leave your comments here.

Saturday, February 26, 2011

A2ZCNC Leadscrews Upgrade - Fabricating the Z-Axis Stepper Motor Mount - Almost completed

This job seems to be forever.  Some progress today, though not very much.  At least the stepper mounting plate is completed.

I started the session wanting to complete the flycutter to be used with the ER16 spindle.  But the setup was done in the previous session 2 days ago for the stepper mount and I've only 2 screw slots to complete with this setup.  So I decided to finish up the stepper mount before moving onto the flycutter.

The slots for the 2 #8-32 SHCS are to allow the mount to be adjusted to accommodate the thicker A2ZCNC leadscrew and anti-backlash nut, allowing some bit of inaccuracy.  A 3mm endmill was used for the through hole slot and 5mm for the counterbore.  The 3mm endmill bought from Mike works rather well but I can't say much about the 5mm TiN coated from unknown origin.  It was bought from RightMicro, which also has a store on ebay.  The 5mm cutter chatter like no tomorrow with the same parameters as the 3mm.  But the simple job was done.

I tested the stepper mount and the anti-backlash nut mount with my spare column bed, which I replaced with the 15" bed from Sherline.  Seems to fit rather well.

Some pics as usual:



Running the gcode for the 2 slots


Good fit!
Testing with the stepper motor mount taken from the lathe
Leadscrew and anti-backlash nut mount installed
Nice...  May leave the mount as a rectangular piece to allow the installation of a home switch

I will be tweaking the anti-backlash nut mount a little to allow the spindle to go lower a bit more.  This will be some kind of extendingTang Kee's mod with Sherline's column travel extension.  Let's see how things turn out.

We'll be having our first meetup tomorrow (or should I say today since its 1.20am now...) at Mike's shop.  So far only 3 confirmed attendees; Tang Kee, Terence, and myself.  Steve didn't reply to my email on the invite.  He may be too busy with work.

Thursday, February 24, 2011

A2ZCNC Leadscrews Upgrade - Fabricating the Z-Axis Stepper Motor Mount - Part 2

After being certified to be competent to continue to work for my organization, I hitch a ride back from my colleague back home.  I was almost tearing up my day job working gear when I got home and headed straight for the shop.

The first thing to do is to face off the motor mount that the tool dug into, spinning the column out of alignment.  About 0.5mm was removed from the surface to rid it of the ugly tear marks.  This leave me about 11.5mm in thickness.  Next, I spent quite some time figuring how I should hold the workpiece with what's available on hand to profile the semi-circle to clear the leadscrew.  The running of the code took a while to complete as I was going at 0.25mm per pass with an 8mm endmill to avoid the same problem encountered in the previous session.  Feeds was also much slower.  Guess the last incident really freak me out.

Ok, some pics posted below to keep up with tradition:


Flycut away those ugly marks.

Pretty much cleaned up. This also show good effort in tramming the mill from left to right.  Front to back is off by 0.01mm.  No big deal.

The workpiece was mounted on the 1-2-3 blocks (actually 25-50-75).  The 8mm endmill was also zero'd to the bottom right corner.  I'm now ready to run the gcode.

About 1/2 way through.  Total of 40 over passes.
Finally through!!!
Ok, I believe this is a simple job for most.  The difficulty I encountered was work holding.  I thought of using the 2 clearance holes further away from the area I'm milling to fasten the work to a piece of wood or scrape piece of aluminium.  But I do not have long enough metric screws to go through them and I do not have tap for those that are long enough.

I'll be leaving the nut mount rectangular.  Once the precision leadscrew is up, I'll be working on a better piece.  Likely to go with Tang Kee's design, which is a modified version of Graham's.  Tang Kee's design seems more suitable for mills with the 8 directions column as it allow the spindle to go lower.

Time to sleep.  It will be 2am in 4 mins time...

Friday, February 18, 2011

Bearings with flange

Finally back in the office after my late lunch. Saw a shop selling bearings on the way back. Went in to ask for some bearings with flange. Bought 10 pieces. I want to try making some ball bearing thrust collars for the mill I'm putting together. Each piece cost SGD5 excluding tax. Expensive for a little guy.

Fastener & Laksa

To me, they seem associative; when I'm here to buy screws, I'll have a bowl of my favorite laksa.

If laksa, sound foreign to you. It a nonya dish (please correct me if I'm wrong) with thick coconut milk gravy served with rice noodle, fish cakes, and cockles. The stuff wrapped in banana leaf is otah, kind of BBQ fish. Yummy...

Screws & Nuts

2 days in a row I'm at Kelantan Lane buying fastener for my projects. Couldn't get exactly what I need but some mod can be done to adapt.

Monday, February 14, 2011

Flycutter: Turning the blank

Ever since I bought the ER16 spindle, I've been looking at the tools I've often use to make sure that when I switched over from the stock MT1 spindle, I won't be forced to switch back in the midst of a job and tram the mill.

Two tools were identified: flycutter and jacob chuck.  Some may add the 3 and 4 jaw chucks to the list but I've not seen the need to use them on the mill for what I've been doing so far.  To tackle the jacob chuck, I ordered a M22 threaded arbor blank from A2Z through Mike of SG Tooling, who is now their dealer in Singapore.  This arbor will be turned and threaded 3/8- 24 to fit the chuck.  I'll write about that when I received the blank.  For the flycutter, I've the necessary to get started.  So it will be the 1st of the 2.  I know that I've not completed some of the jobs I started, but its a hobby.  I flow with my feel...

The "plan" was from Dean Williams' build log, a wonderful site which I frequent.  Check out his site here: http://www.deansphotographica.com/machining/projects/projects.html/.  Dean, thanks for replying to my email earlier today.

Anyway, some pics of my progress:

Using the Proxxon Mitre Saw to cut off a piece of 1" dia mild steel rod 2" in length. That's the max depth I can cut with this very worn Corundum-bound cutting disc.
Changed the worn disc to a brand new cutting disc but the new disc disc broke off from the arbor. 

Finished of the cut on the Proxxon vertical bandsaw.

The stock mounted on the 3-jaw for turning.
Turning to 10mm for the shank.
Flipped over to clean up the other end for the tool holder.
Look at what Tapmatic cutting fluid did to my chuck beside giving me a headache...
Chamfering the back to give it a better look.
Turning job completed.

This is where I stopped, after mounting the 3-jaw chuck to the angle plate. The angle plate was set to 20 degree.

I setup the job on the adjustable angle plate to mill or flycut at 20 degree.  It'll be slotted to hold 1/4" left hand lathe tool to be held by 2 10-32 setscrews.  I stopped here because I'm not sure if the setup is rigid enough.  So the question was posted on SherlineCNC group.

I'll put in some more work, hopefully completing this job tomorrow night, before I go back to work on the Z axis mod.

Saturday, February 12, 2011

Leaf in Aluminum

Was at Mike's shop when he show off what he did to a customer's of his. I took the chance to take pic of both leaves side by side. I still like the one in wood. With the grain, it looks pretty, though I don't really like to work with wood. Hard to clean up after machining.

A defective cut off wheel?

I was cutting off a piece of 1" dia mild steel round stock using the Proxxon Mitre saw to make a straight shank flycutter. It was a painfully long process as I didn't want to push the mitre saw too hard, especially after burning the bandsaw motor.
Almost 3/4 way through, I saw that the cutting disc is rather worn and will unlikely cut through the 1" stock. A new disc was swapped in. After only a few second of using the new disc, the mitre started making some strange noise. I quickly unplug it and saw the disc wobbling to a stop. This was what I saw when I removed the guard:


Seems that the new disc centre hole has given way. The old disc was swapped in to cut till it's max and the rest was finished off with the bandsaw.

Looks like the purchase of a horizontal bandsaw can now be justified... I'm just weak in my mind, to the temptation.

Monday, February 7, 2011

Collets Organiser - Terence's Creation

Terence sent me this. He seems to work mostly with acrylics and copper (ie, PCB milling). This guy is good, started with zero less than a month ago to milling out his PCB.

The PVC drawer is from Daiso, the everything at $2 shop.

Nice job Terence!

Sunday, February 6, 2011

Simple Tramming Tool - Part 3

The tramming tool is now completed.  I ran into a little problem trying to tap one of the end of the shank.  The problem has been bypassed by using high strength loctite to hold the shank to the body.

I started this morning drilling a 4.2mm hole on the lathe to prepare to tap M5 at one of the end of the steel rod.  Drilling went on ok but the tap refused to go in.  It went in a little but the stock started to turn in the 3-jaw chuck a couple of mm's into the hole.  I tightened the 3-jaw further and turned the tap like no tomorrow, being careful not to break it.  The tap was withdrawn from the hole for inspection -no thread was seen except some mess in the little area I managed to get the tap in.  I was almost filling the hole with light oil hoping to get the tap to work.  It didn't.  I'm frustrated.  I went on to clean up the work area and the rod, and use the high strength loctite instead.  Will leave it to cure while I'm out to church before putting the tool in use.

While cleaning the work area using a magnet to suck up the swarf, I realized that it doesn't stick.  Mmmm.... I remember my good Irish friend, Hamilton, once told me about some steel with certain amount of carbon its composition has no magnetic property or something.  Need to dig out that email.  I posted my problem on MEworkshop list and gathered from there that the rod is stainless steel.

When I got home, the loctite seemed to cure.  The assembly didn't move while I tried to rock it hard.  The 2 indicators were mounted and the whole assembly went on the mill spindle using an 11/32" ER16 collet.  Just when I thought I'm able to tram the mill right away with the new tool, I realized that one of the indicators has a flat battery... I'll go get some later since we are attending a little boy's birthday party in the evening.

Once the mill is trammed, I'll be making another tramming tool with the indicators mounted on top rather than sides.  I feel so much more confident drilling with the mill than my drill press.  There must be something I didn't do right when using the drill press.  Got to find out the reason.

The tip of the tailstock dead centre has worn out after only one use.  Think I may have press it against the stock too tightly.  Couldn't help it as the stock came loose a couple of times.

If you look carefully, there isn't any thread being formed.  Thought I saw a couple but may have knocked them off when trying very hard to get the tap to turn.

Gave up tapping and use the high strength loctite instead, leaving it to cure while I was out.

The joint seems tough. Can't twist the shank off the body of the holder.  The 2 indicators mounted. A plate glass was used in the pic to rid the problem of the narrow table and tips falling into the slots.

I'll start tramming once I replace the battery in the DDI.  Will be back in completing the offsetted motor mounting plate for the Z axis leadscrew mod soon.

Saturday, February 5, 2011

Simple Tramming Tool - Part 2

I found some time in the morning of the 3rd day of the Lunar New Year while my wife was preparing for her friends' visit to our place.  Started only wanted to drill the 8mm hole on the beam of the indicator holder, leaving the steel shank till later date.  But I persisted on after we sent off our guests and stop just in time for my showflat duty at 3.30pm.  The shank was turned down to slightly below 8mm, at 7.995mm.  Tested the fit - the best I can achieve (frankly, I've not done any of such and therefore, nothing to compare with...).

The 3/8" steel rod which is to be the shank was cut from a long piece I happened to have in my stash.  The Proxxon mitre saw was used to cut it to its approximate length and faced off in the lathe to about 80mm long.  The 2 ends were centre drilled so that I can turn the steel rod between centres.   I initially opted for the revolving centre at the tailstock end, but the diameter of the part holding the bearing prevented the tool to reach the end of the steel rod.  The dead centre was used instead. Despite that, I've to turn the tool at an angle to reach the tailstock end of the steel rod.  As I'm unable to reach the headstock end because of the cross slide getting in the way (QCTP was fastened to the slot further away from the headstock to reach the tailstock end), my plan was to turn down half the length of the rod and flip the stock around for the other half.

The cut was made with 0.1mm each pass (0.2mm removed in diameter).  After each pass, I would measure the diameter at each end of the cut to square up the lathe.  From a taper measuring a difference of 0.09mm at cut length of about 40mm on the first half, I managed to bring that down to 0.03mm.  Couldn't seem to lower this figure anymore than that.

After both halves were done, I tested it on the beam that will be holding the 2 indicators.  It fits with a slight twist.

2 options are now available for me to complete this; 1) drill and tap M5 at one end of the steel rod and fasten the shank to the beam using a M5 cap screw, 2) loctite them together.  I'm likely to go with option 1 as the beam to hold the indicators wasn't well made.  Once the mill is squared up, I'll make a replacement with more accurate hole placement.
Some pics as always...

Drilling the 6mm through hole after centre drilling.
The 8mm hole is drilled to a depth of 10mm leaving about 5mm in the stock for the cap screw.
The 2 holes are not very concentric.  Wonder if I would have problem later...
The unknown steel of about 3/8" in diameter and slightly more than 3" in length.

Testing for fit. A slight twist bottoms the shank.  Good stuff!

Flipping the rod around to turn the other side.


Turning operation done!  Not too bad a surface finish.

This is how the tool will look like. 

I didn't take any pic with the indicators mounted.  Will do that when I tram the mill.  Hope to get back to the z axis mod real soon.


Thursday, February 3, 2011

Simple Tramming Tool - Part 1

Before I can get on with the rest of my work, the mill needs to be trammed.  In my previous post, I created the model to give me a feel of the dimensions and how it should look when completed.

Mike of SG Tooling helped me to prepare a piece of square aluminium stock for the job.  What I need to do is to drill the mounting holes for M5 and an 8mm hole to mount a rod which will go into the spindle.  I encountered quite some problem with drilling the hole as the drill wondered despite having a centre punched mark.  Persevered through the job with one of the tap holes off centre.  Couldn't proceed further in fear of incurring the wrath of my beloved.

The stock measures 15mm square with both ends trimmed with Mike's help.

Measuring the stock to layout the hole locations. The height indicator was used on the glass table top before the surface plate followed me home.

Centre punched to avoid the drill wondering everywhere.

Still, the centre drill wondered around, resulting in off centered hole.  The hole is also not round.

Using the drill press to start the M5 tap.

Removed from the drill press to continue tapping by hand.

The 2 digital dial indicators mounted with M5 cap screws. 

This is how it should look like when done.

It may takes me awhile before I can get back to the shop to continue my work.  Don't think I've the blessing with this hobby of mine.