I finally made my first fixture today, I never really had to use jigs or properly set-up a piece using an edge finder. Well, I did it today for the first time. Like I said, Never really needed to, so I never bothered.

I needed to make a fixture for my Taig, this was a fixture I designed a few weeks back. Cut everything today on separate files, man the edge-finder really makes life easy! I'm glad I can use it now.

I can't say what the fixture is for (Top Secret) but this will make repetitive milling easy and 3-d milling fast.

I thought I drilled the holes for the Dowels a few thousands smaller but apparently I didn't. It's snug, but can be twisted. Maybe I can just loctite them in!


I inverted the pictures so you don't have huge glare, plus it looks awesome.

http://i9.photobucket.com/albums/a96/SpeedsCustom/3years100-2.jpg
http://i9.photobucket.com/albums/a96/SpeedsCustom/3years101.jpg
http://i9.photobucket.com/albums/a96/SpeedsCustom/3years102-1.jpg


-Jason

The 540 cuts fine, the reason things got so messed up the first real cuts were because of Speeds and Feeds/Clamping.


-Jason

Speeds and feeds seem so arcane but most good tooling suppliers list the speeds and feeds for their stuff and you can always scale it back for your machine.

It is looking good and I am glad to see that you are well on your way to making your first million with a Taig.
Mike

Hi Jason.

I am still learning. Can you explain what is the jig for? Thanks.

Alex

TotallyRc- Oh and yea, the right sharp tool works too! Lots of my tools were given to me (New) So It was like impossible to try and look them up.

Alex- I can't say what the Jig is used for right now, but. By making the jig, it's makes set-up of a continuous part very easy. I don't have to load each new piece and make sure it's parallel to the table and so on. The locating pins will always center my pieces.



-Jason

Hi Jason.

I am still learning. Can you explain what is the jig for? Thanks.

Alex

It's a secret; if he told you he would have to seek you out and eliminate you. :)

To help your learning I will be picky (as usual); it is not a jig it is a fixture, they are different.

A jig is a device which secures and aligns the part to be machined, and also guides the cutting tool. An example would be a drill jig with hardened steel bushings that the drill passes through into the part.

A fixture is a device that just holds and aligns the part for the machining.

This was a distinction made way back in the dark ages when I was an apprentice fitter, turner and toolmaker.

Ah yea there we go, A fixture! Not a jig! Sorry folks, I went ahead and even changed it. GEOF has corrected me and I went back and changed it. Thanks, and yes. I made a fixture.


-Jason

Don't forget you can also dance a jig..... :)

Nice job on the fixture.

Fixture seems to be for 3D two sided job;)

and of course you have to remember that a fixture is only as good as it is indicated square ............ :)

I get it now. Might make one for myself. Thanks.

Fixitt- Very true, it need to be square to work just right, or the alignment won't be right!

Khalid- Yes, 3-D model

Thanks to the comments.


-Jason

TotallyRc- Oh and yea, the right sharp tool works too! Lots of my tools were given to me (New) So It was like impossible to try and look them up.

Alex- I can't say what the Jig is used for right now, but. By making the jig, it's makes set-up of a continuous part very easy. I don't have to load each new piece and make sure it's parallel to the table and so on. The locating pins will always center my pieces.



-Jason


You can always just use a generic speeds and feeds calculator as in the machinist hand book and it will get you in the ball park. Sharp cutting tools are a beautiful thing.

I won't as what the "FIXTURE" is for as I don't want you to hunt me down and deal with me if you tell me. You might even do a "JIG" on my head. LOL

It is hard to believe how much time goes into fixturing something before the first part is made.

Time for bed, I am getting groggy and I still have to go to work tonight.

Mike

Here are a few hints for fixtures:

When you have the plate fastened down for drilling the locating pin holes at this stage also machine two edges of the plate, and make a note of the distances from the plate edges to the midpoint between the two pins. Now you find your pin locations just by using an edge finder on the plate and doing a bit of math. Also interpolate a small hole at the midpoint between the pins so that you can locate them using a coaxial indicator which is quicker and easier than an edge finder.

......It is hard to believe how much time goes into fixturing something before the first part is made.....

But, if you will be doing more than two parts and spend a bit of extra time making a fixture the time you save overall can be significant.

A lot of time does go into making a fixture. And I don't think i'm done yet.I feel like more work is still to be done on making sure that set-up is easy and quick.

I also made a slight error in todays cutting. Where I drilled two holes for piece to be cut at a random Y. So when I put the work piece over the mounting holes. I was few thousands off in my Y-axis. So obviously the part cut well on the first side, when I flipped it, it did not line up correctly due to set-up error. I confirmed this by not only theory, but by jogging the Z-axis down onto the pin and seeing that it was not perfectly centered over the pin. Giving me my error.



I just made a few more cuts on the fixture. Squared off all the side instead of the rough cut from the factory. Should give me better results when I located my edges.


-Jason

Jason........
instead of trying to remake the fixture, why dont you indicate the PINS square. Instead of trying to indicate the edges? If your pins are in line, the bottom plate can be off by inches......... but as long as the pins are aligned, so should your part. Right?

Yes you are correct. I'm not re-doing the fixture. I do however need to make new holes. The holes I made were slightly larger then the pin, just slightly. So this becomes a pain when they decide to lift.

The reason I need to locate the edge for the Y-Axis. Is when I load the material onto the fixture I will have to move the table around. When I LOAD THE 3-D file, I need to know the center point. Knowing the distance to the center of the holes will allow me to set the 3d file accordingly.



But here is why my part was off. The 3d model is set-up so that it is in the center of the of the part, no matter what it is. So when my tool was not centered with the pins, when I flip it...it will be off by however much I was off on the set-up. I try and make sure that every program I run stops in the center, it's the first initial set-up that determines everything! The only thing I would need to do is reset the Z. Nothing else.






This stuff is a mind game!

-Jason

I feel your pain dude! Working with artcam jewelsmith everything I do is in the center of the part. X Y Z a ever so slight mis calculation can throw off 8 to 12 hours worth of machine time.

It is for this reason that I no longer machine on the table of the machine anymore. I made a fixture to hold my stock that fits my rotary table. Everything I do is off of the rotary. Plus im cutting wax not aluminum. But still I do feel your pain. :)

Speed,

Do you need to ream the hole for the pin?

PDB

Hi Guys

:wave:
Here are a few hints for fixtures:

When you have the plate fastened down for drilling the locating pin holes at this stage also machine two edges of the plate, and make a note of the distances from the plate edges to the midpoint between the two pins. Now you find your pin locations just by using an edge finder on the plate and doing a bit of math. Also interpolate a small hole at the midpoint between the pins so that you can locate them using a coaxial indicator which is quicker and easier than an edge finder.

Great advice :)

But, if you will be doing more than two parts and spend a bit of extra time making a fixture the time you save overall can be significant.

Don't I know it. Some times even when doing one part it can help, especially if the part has to go back on the machine (nuts)3 or 4 times because you are engineering on the fly.(chair)

Speed,

Do you need to ream the hole for the pin?

PDB

It will give you the best fit and retention of the pin. A .002" press fit should be plenty but if you use a drill the finish of the hole is rough and the tolerances are not as close as with a ream.

Here's a fixture trick taught to me by my dad.

Take a length of 1/4" by 1" by long length of cold rolled steel and bolt it to the back edge of the table of your milling machine so that the top is 1/2" above the table (more or less). Since the edge of the table is square with the travel, you then have an edge that you can use for alignment.

When I place a fixture on my table, I use that edge. I just lay a couple of 1/2" dowels on the table, press the fixture against them with the dowels against the edge and know that the fixture is aligned.

If you have some wide work, you might have to remove the edge, but so far, that hasn't happened for me. It sure saves a lot of time.

You can do the same thing by using the Tee slots for alignment.

(I know that some people have a problem drilling holes in the tables of their machines; but hey, it's just a tool. Now, when I put the first dent in my daughter's head, then I felt bad.)

Ken

(chair)Dear Kenneth, say it isn't so, you must have been taken over by the :bat:darkside :bat:to even suggest that the acres of pristine cast iron be violated by cold hard steel and result in a (GASP) hole in the work surface.(chair)

:):):):):):):):):):):):):):):):):):):)

All kidding aside, a couple of stratigically placed holes can make all the difference for certain fixtures. Or your idea is a good one that I hadn't thought of.
P.S. I am in Simsbury CT.

Easiest way to align parts clamped to the table (assuming the tee slots are in fact parallel to the x axis travel) is to insert dowel pins vertically into said tee slots. I have an assortment of 5/8 hard dowel pins from my knee mill days. I have to source 14mm pins for my RF45. Hadn't even thought to look for them yet, but first I will verify that the tee slots on my table are in fact parallel.
Joe

Easiest way to align parts clamped to the table (assuming the tee slots are in fact parallel to the x axis travel) is to insert dowel pins vertically into said tee slots. I have an assortment of 5/8 hard dowel pins from my knee mill days. I have to source 14mm pins for my RF45. Hadn't even thought to look for them yet, but first I will verify that the tee slots on my table are in fact parallel.
Joe

Indeed, this is the way I like to fixture on the Taig as the table T slot on mine does in fact run parallel quite nicely. I usually mill a keyway to fit the exact width of the T slot so that location is a breeze.

[QUOTE=TOTALLYRC;512631](chair)[B][SIZE="6"]Dear Kenneth, say it isn't so, you must have been taken over by the :bat:darkside :bat:...snip.../QUOTE]

I made the suggestion about drilling alignment holes in the machine table and got a response similar to this; the only difference was the poster was serious.

On my first (manual) mill I centered the table on the spindle, locked the handwheel graduation rings (and never moved them) and bored an accurate 0.500" hole in the table. Whenever I needed to tram the head after using it at an angle all that was needed was the table centered at 0,0, a 0.500" dowel in the spindle brought down into the hole with the head bolts loose and the bolts tightened. Saved hours of time over the years.

As it turns out 14mm is not an easy dowel pin to find. I will turn a few out of CRS, but I do prefer them hardened.
Joe

[QUOTE=TOTALLYRC;512631](chair)[B][SIZE="6"]Dear Kenneth, say it isn't so, you must have been taken over by the :bat:darkside :bat:...snip.../QUOTE]

I made the suggestion about drilling alignment holes in the machine table and got a response similar to this; the only difference was the poster was serious.

On my first (manual) mill I centered the table on the spindle, locked the handwheel graduation rings (and never moved them) and bored an accurate 0.500" hole in the table. Whenever I needed to tram the head after using it at an angle all that was needed was the table centered at 0,0, a 0.500" dowel in the spindle brought down into the hole with the head bolts loose and the bolts tightened. Saved hours of time over the years.

I swing an indicator on the table to tram the head. Only way to guarantee perpendicularity.
Joe

scudzuki,

Just what the cook ordered.

http://tinyurl.com/4bmo8w


Jeff...

Thanks, good find.
Joe

Similar to what someone said about the bolt up the steel to the back of the table. The way I have been aligning my fixture is using 1-2-3 blocks and butting it against the back or front of the table. Same concept :)


-Jason

Table slot pins require no adulteration of the table. Handy when your employer might not look favorably upon adding holes to their machine. The rail on the back edge is handy, too, and of course can be removed when not needed.

Joe