The Home Machinist!

Hello,

I am new to all this machinist stuff so forgive any newbie errors.

I bought a grizzly milling machine. The low end model.

My question involves the mill's accuracy and what is acceptable.

For instance...I bring the end mill down and travel it across the x axis for 3 inches. During that span the table(?) drops about .003 inches. Is this acceptable?

thank

cyrano

Welcome to the group!

Do you have the model number of the mill so we can get an idea which one it is?

Is there a quill lock that was possibly left unlocked or possibly a collet not tightened properly? Either of which would allow the end mill to pull itself deeper into the work piece.

Just guessing without further details.

_________________
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

Its a Grizzly 8689.

I put the end mill in the collet and tighten it with the key. Is there something I should else to check on the Collet?

thanks

Do you have a dial indicator you could hold in the chuck and then rest the point on the table? Then crank the X axis and see if the indicator needle moves to see if there is a problem with the table inclining.

It's not a good idea to hold end mills in a drill chuck when milling. You should hold them with MT-3 end mill holders plugged into the spindle.

_________________
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

It looks like you have two lock levers on the right side of the spindle casting that are used to lock the casting to the vertical column after you set your cutting depth. Make sure that they are locked so that the casting does not creep down when milling.

_________________
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

Sounds like it's just not in tram, as Glenn has suggested with the table and indicator! Looking at the base it appears as though you can tilt the head. Maybe try and sweep the table with a DTI out serveral inches to see what it reads from one side to the other.

these mini mills have historicaly had some flex issues in the collum

here is one mans attempt

Grizzly 8689.


http://www.homemodelenginemachinist.com ... pic=6075.0

this will get you thinking

I Love this Forum!!

I will be ordering the following:

- dial indicator
- Mt3 mill end holder

Once I have a dial indicator I will have a better idea what is going on with the table.

I have come to the conclusion I cannot determine my table tilt(?) with just putting the end mill down in places along the table. This is because I am finding its hard to tell when the micro down feed knob is down as far as it can go on the table....seems to depend on how hard I am willing to twist it. Does anyone agree with this conclusion?

Looks like the dial indicator solves this issue.

The mill end holder will solve the issue with how tight the collet should be tightened (correct?)

Thanks to everyone for their time. I will be reporting back in about 2 weeks when I have time to do this get this stuff and take some measurements.

cyrano

Agreed! there is not way to tell from dialing the quill down, you'll get a different measurement every time. Get a DTI and mount it in the quill, then zero it on the left and sweep it around to the right and read the measurment. Adjust accordingly. I can't hazard a guess at what reading will be front to back. It may require some fancy fixturing to adjust that.