Tram a CT129 BUSY BEE Mill

[Brian Rupnow]

I am in the process of tramming my CT129 milling machine from BusyBee tools in Canada.--Does anyone have experience with this. If so, please step up. I haven't done this before and would welcome advise from anyone who has done this.-----Brian

 

[Brian Rupnow]

I've just been reading through the literature which came with my mill. It appears that I have two possible sources of tram problems. Not only does this mill have some adjustment for squareness of the column in relationship to the bed, but it also has a rotatable head. I looked under the head, behind the spindle, and sure enough---There is a rather coarse protracter and pointer, as well as a locknot to lock the head in any angular position.---Now I'm thinking---since their is no discernable looseness nor wobble to the column, which is bolted to the base with four good sized bolts, could this be as simple as loosening off that lock nut and using a dial indicator held in a 3 or 4" long bar to reset the head rotation? --Brian

 

[Brian Rupnow]

Before I made any changes, I placed my digital protractor on the bed and zeroed it, then put it on the side of a round rod held in my drill chuck. At any rotation of the chuck, it claimed there was 0.5 degrees off of the correct 90 degree angle when measured parallel to the long axis of the bed. This was only to give me a rough idea of the "out of tram left to right" measurement.. I then unscrewed my dial indicator stand from the magnetic base and gripped the stand in the chuck. I mounted the dial indicator 6.75" out from the chuck, and took a reading at full left sweep and full right sweep. The dial indicator said that there was a total difference of 0.120" from extreme right to extreme left (which was over a total distance of 13.5"). I loosened off the locknut which held the head vertical and proceeded to tap the head untill the dial indicator moved .060" at one end, which should have put the table exactly at right angles to the spindle. After much tapping and friggery ((The head doesn't rotate easily) I managed to get the same dial indicator reading at full right and full left sweep. I then locked the nut back up, and rechecked with the dial indicator. All seemed to be well. Then to confirm that I hadn't totally messed up, I checked again with my digital protractor and got a reading of exactly 90 degrees difference between the spindle and the bed of the mill, measured parallel to the long axis of the bed. I will add here that the locknut and pivot on the head will ONLY allow the head to pivot left to right, not back to front, so I wasn't worried about tram front to rear of the mill. Once everything was finished, I made a quick CAD sketch of a triangle with a base of 13.5" and a rise of 0.120"----The resultant angle was very close to 0.5 degrees, so I am relatively certain that I have corrected things.----Brian

 

[f350ca]

Sounds about right Brian. I have a Bridgeport clone so you have to tram it in both directions. I found an old ball bearing about 6 inches in dia, I lay it on the table and adjust the dial indicator to sweep around it while in the chuck. Something similar would check front to back for you. If its out guess you have to shim the column.
Greg

 

[ninefinger]

Brian,

I have a slightly larger mill (RF-45 type) but I'll share my experience with tramming as it may well apply as the basic style is the same (ie benchtop bed mill).

I needed to "level" the bed of the mill. I use level in quotes as its not really level you're trying for but removing any twist that may be present and using a machinists level is the easiest way. Before I leveled the mill I could tram in the column against a cylinder square and have everything good and then move the table and check in another spot and it was way out as I moved up and down.

Turns out there was a noticeable twist in the bed as the table was moved front to back - I could watch the level bubble go from one extreme to the other over the 11" of travel! Anyways, tightening down the bed and checking the level I got it so that it was basically leaning ever so slightly to one side the same amount front to rear. The I was able to tram the column and it stayed in tram over the travel of the table.

Hope this helps.

Mike

 

[steamboatmodel]

There instructions on setting up sure don't help much, other than telling you to level the table and then zero the head pages 6 & 7. Best of luck.
http://www.busybeetools.com/product_manuals/CT129.pdf
Regards,
Gerald.

 

[Don1966]

Brian you may want to check the tram on the y axle just to see if it is warped or twisted. I have a Micro Mark mill built by the same people who built yours. My mill would fly cut steps as I moved the y axle. The only way to correct this is with shims. Also Swart Rat has a video on how to correct the bed twist and tram the mill, also disassemble and lube it. The video is not very expensive even for someone like me who had never done it before.

Don