I got my Grizzly mini mill a year ago and had to add shimms to dial the head in as it was .003 out from the table, Ive checked it several times sense then and all was good, now that I got some hours on it I decided to clean up the gibs too help with a smoother run, they were really rough so got them nice and smoothed out and re installed, now after checking the head agin is out .003 on the Y axes from front to back, it seems long enough(the gib) that if it did get more off one end it wouldnt get that far out, anyone know what happened ? I havent re shimed yet thanks ED
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Re tramming after gib clean up
- Thread starter edowens
- Start date
Can you take some pic's of what your trying to describe? I'm a bit confused with what your saying. Where did you shim the first time? Do you mean circle sweeping with a indicator on the top of the table? Usually the gib doesn't affect the sweep unless there is some trash under the table and the gib isn't pulling it done correctly. If you can call me so I know what your saying. 651 338 8141 Rich ( I am a professional Machine Rebuilder)
Rishard, I shimmed under the front of the colum @.003 when I first recieved the mill, and yes I did a cir sweep with a DI, RE-tramed left and right (X) axis as it has a tilting colunm that I dont use, but check before each use. this is the first time I found the (Y) axis out sence the first tramming, (front to back) I can re tram it but was wondering why it got out of tram, I allso took the the X table off and cleaned up /reoiled and greased the lead screws on both tables I do this a cuple of times a year but this is the first time cleaning up gibs and yes I did the Xand Y gibs allso hope this helps you find what I did wrong thsanks agin ED
First of all, I have to say I have seen 3 "Rung Fo" type milling machines dismantled and as a professional rebuilder who has been rebuilding machinery for over 40+ years. Mostly on American, Japanese or European made machines. Those 3 imports were bad with poor workmanship. In a recent Rebuilding / Scraping class, 2 of the hobbyist students brought their imported machines to repair.
One was a Rung Fo type mill and one was a small mini lathe. The Mill was a mess. We measured the base and it as out of parallel .010" The table was out of parallel by .008" (4 corner and middle Mic of table). The student said he was always tramming his machine and shimming it too a lot before the class. So trying to understand why you have to tram is the machine was not built accurately in the first place, so I can understand why you are getting frustrated with your machines.
A simple test will be to mic or use a vernier caliber to measure the thickness of the tables 4 corners and middle if it is apart. They should be with-in .001".
Now trying to help you.
First I would like to ask, what the machine sitting on? A heavy-duty table or stand? Is the machine solid on its stand? Is it bolted to the stand? Take a feeler gage and see if you can slide in a .0015" or .002" shim under the hold downs. If they are loose make up some shims that look like a flat washer (you can buy a plastic shim pack from MSC http://www1.mscdirect.com/eCommerce/NavigationServlet?ta=Y&N=12101788. and slide in the shims and tighten the hold down bolts. Some have leveling screws with a pull down bolt in the middle.
What ever method works, the base needs to be solid and tight where it is mounted. I also use a precision level to test how level the machine is and I check how parallel the ways stay when I move the table and saddle with the level sitting on the table Also a precision square to check X, Y and Z squareness (can tell you more about that another time if your interested). You can also indicate the table top by not tramming it but cranking the table and saddle left to right and in and out. This should also be less then .001". Is your stand solid on the floor?
Take the gage and check the machine and see if you can slide the shim between the base ways and bottom of the saddle, between the saddle and table? Can you slide it in where the gibs go? If you can tighten the gibs so you can move the axis, but can't fit in the .0015 gage in it. I use a dial indicator to check this to check the "shake" and on a precision we like to see .0005" to .001" for a thin film of oil.
Does your machine have lock screws on table and saddle? Do you lock the locks when you tram? If you have to re-tram the machine 3 or 4 times a-day then something is loose or screwed up.
You may want to take apart the machine and assemble it with way oil and not grease. Before you spread it on , wipe the metal off with your hand. Not a rag as a rag will leave lint or dirt on the ways. When you use your hand you can feel the dirt. You can blow it off with air (wear your safety glasses) and then wipe it off with your hand and assemble it. My students mill was so messed up we had to scrape it to correct the errors from the factory. The mini lathe was also a nightmare and we had to scrape it.
We usually don't use grease because dirt sticks to grease in open air and turns to lapping compound ruining the machine.
Do those checks and let me know.
Rich
Use this method with mag base and indicator to check the gibs "shake" on your mill.
One was a Rung Fo type mill and one was a small mini lathe. The Mill was a mess. We measured the base and it as out of parallel .010" The table was out of parallel by .008" (4 corner and middle Mic of table). The student said he was always tramming his machine and shimming it too a lot before the class. So trying to understand why you have to tram is the machine was not built accurately in the first place, so I can understand why you are getting frustrated with your machines.
A simple test will be to mic or use a vernier caliber to measure the thickness of the tables 4 corners and middle if it is apart. They should be with-in .001".
Now trying to help you.
First I would like to ask, what the machine sitting on? A heavy-duty table or stand? Is the machine solid on its stand? Is it bolted to the stand? Take a feeler gage and see if you can slide in a .0015" or .002" shim under the hold downs. If they are loose make up some shims that look like a flat washer (you can buy a plastic shim pack from MSC http://www1.mscdirect.com/eCommerce/NavigationServlet?ta=Y&N=12101788. and slide in the shims and tighten the hold down bolts. Some have leveling screws with a pull down bolt in the middle.
What ever method works, the base needs to be solid and tight where it is mounted. I also use a precision level to test how level the machine is and I check how parallel the ways stay when I move the table and saddle with the level sitting on the table Also a precision square to check X, Y and Z squareness (can tell you more about that another time if your interested). You can also indicate the table top by not tramming it but cranking the table and saddle left to right and in and out. This should also be less then .001". Is your stand solid on the floor?
Take the gage and check the machine and see if you can slide the shim between the base ways and bottom of the saddle, between the saddle and table? Can you slide it in where the gibs go? If you can tighten the gibs so you can move the axis, but can't fit in the .0015 gage in it. I use a dial indicator to check this to check the "shake" and on a precision we like to see .0005" to .001" for a thin film of oil.
Does your machine have lock screws on table and saddle? Do you lock the locks when you tram? If you have to re-tram the machine 3 or 4 times a-day then something is loose or screwed up.
You may want to take apart the machine and assemble it with way oil and not grease. Before you spread it on , wipe the metal off with your hand. Not a rag as a rag will leave lint or dirt on the ways. When you use your hand you can feel the dirt. You can blow it off with air (wear your safety glasses) and then wipe it off with your hand and assemble it. My students mill was so messed up we had to scrape it to correct the errors from the factory. The mini lathe was also a nightmare and we had to scrape it.
We usually don't use grease because dirt sticks to grease in open air and turns to lapping compound ruining the machine.
Do those checks and let me know.
Rich
Use this method with mag base and indicator to check the gibs "shake" on your mill.
Last edited by a moderator:
We retram 3 or 4 times because we are setup to do it quickly and we are running lots of parts that are obviously required to be within specs. Sort of like preventive maintenance. I have found that people who don't like to or don't tram do not have dedicated equipment to do so. I require it. Its an acquired skill to do it correctly and practice makes perfect. And Im interested in you continuing with your methods.
I'm trying to help you. I do not know your job and have to generalize on all these posts. Indicating in a part is normal procedure but tramming in the machine table because your worried it is out of whack 3 or 4 times a day and or re-shimming the column each set up is because the machine has alignment issues or the machine is in need of repair. I tell my customers and now the readers here, I do not have a crystal ball and can't tell you what is wrong or how much the repair will cost until I take apart the machine and discover what is the problem. I can make some suggestions from my years of experience.
Thankyou your posts sure are helping me, the mini mill is bolted down good to a very sturdy bench and useing a machinest level I shimmed it to a nats but, I always check the tram before stating a project , usely see Y axis out but this is a first sence getting the mill for the Z to Y , I do know I need to strengthen the colume as its not that good for sure but its what it is for now for us just getting into milling and dont have a ton to spend on a good mill its seems to be ok after a few adjustment, you are right about the quality but as a first one It'll have to do untill the day I can get my hands on a USA mill, I did retram (I took all shims out and cleaned very well) and have it at .0005 on Y and .0007 on the Y , checked the table movenment (play) as you suggested and have .0005 so I;ll keep on learning more and more , I do know after a few broken/chipped end mills how much feed,depth of cut and speed this little bugger will handle. Thanks agin for your replys and letting me be apart of this fine forum ED