Newbie Questions

[Bamban]

Finally got the new to me Bridgeport Series 1 2 HP mill and a 12x36 lathe all moved in and wired up. Currently going through the operations, maintenance, and set up procedures. I've read and viewed a few videos and got some input from machinist friends on the how to operate and set up the machines. Learning this machines for someone with no machining background is like drinking from a fire hose. Glad I am retired I can stay in the garage all day.

One of the mill procedures I am about to go into is the tramming/sweeping the head/table with the indicator on a rod attached to the spindle. Unfortunately, I do not have the proper rod/indicator combination to properly do the procedure according to all the instructions and videos I gathered. The closest thing I can use is the case/ammo run out gauge kit from RCBS that I already have. I cam use the indicator and the rod combination, but the sweep radius is more like 2 1/2 inches, limited by the cross bar connecting the indicator to the rod that is attached to the spindle.

Now the questions.

What will I miss if I were to keep the indicator stationary and I will move the table around at any place from end to end, front to back? Will I accomplish the same thing with the table stationary and rotate the indicator? What is the end result difference between the two methods?

Right now the machine is set at the zero mark for both scales, tilt and nod.


What else do I need to know about these machines that is not clearly spelled out in any of the standard manuals?


Pictures of the machines.

 

[chips&more]

Re: Newbbie Questions

Indicator fixed and moving the table around will only tell you table error and or translation problems. Sweeping with the head spindle will tell you tilt and nod error.

 

[Bamban]

Re: Newbbie Questions

Indicator fixed and moving the table around will only tell you table error and or translation problems. Sweeping with the head spindle will tell you tilt and nod error.

What would be the minimum sweep radius considered to be the lower limit to be effective?

 

[chips&more]

The larger your sweep radius the greater your resolution/sensitivity in seeing any discrepancy’s. You can trig/math out the possibilities. I do it with an arm that can sweep the outer edge width of the table. That way I get the best result I can. And a note on at least my BP and the “0” reference angle head marks that it has. Mine are off! So, I used some of that HVAC metal tape and covered up the original zero or dash mark and made a new relocated dash mark…Good Luck.

 

[JimDawson]

I just use the rods from my standard mag base indicator. Put the big rod in the drill chuck, center on the table, and slide the indicator out to the table edge. I can sweep my 10 inch table to the edges.

 

[chuckorlando]

Truth be told, I would think if you can sweep the distance your working in that would be all you need to work out the error you need. For example if your using a vise and the wor fits in the jaws the only error that matters right then is what you get over the work. If you need to be with n .001 and can get it to .001 over that vice, you would be good.

That being said, I do it like Jimdawson

 

[Bamban]

Thank you all for all the responses. I will report back on the progress.

 

[Bamban]

Well. I could not let the day/night go by and not do something about the mill. I got an Aluminum bar from a friend, the size is close enough for what I need to learn and bought a 3/8 Aluminum rod from Home Depot to construct the indicator holder.

Adjusted the nod first, then the tilt. All bolts are back to spec - 50 ft-lbs. Incrementally got to the spec, started at 25. Lessons learned; there is tremendous backlash in the adjusting bolts, and need to keep the bolts at some tension, just enough to adjust.

Here are the pictures showing the initial readings and where I end up. Did not use a .0005 indicator, but for my education tonight the outcome is good enough.

Did I do it correctly?

 

[chuckorlando]

Should have mentioned that you should keep one of the nuts/bolts good and snug when adjusting. It helps keep the backlash under control and makes tiny moves easier

 

[gredpe3]

Good job on the indicator holder.I'm gonna try to make one myself.Thanks for the inspiration.
Eddie