Bridgeport Micrometer dials

[EmilioG]

Used the mic dials on the BP mill today for the first time.
Worked really well. I used my Starrett 827B edge finder
and was able to locate my holes right on the spot that I
marked off and punched. I really want an Accurite II. Working with the mill
would be a breeze! How much for the complete Accurite set up?
I know theres a lot of hardware to go with the electronics. Is it a lot of work
to install and what kind of tools would I need?

Thanks

 

[chuckorlando]

Much cheaper versions of dros man. I will get a better unit at some point but right now I got 100 bucks worth of igaging dros. Thats all you need to locate holes.

No they aint hard to put on. Might take a little thinking but just a few holes and bolts and wires to plug in more or less

 

[Andre]

Why not use the dials to locate holes? When you really understand backlash, and how to work around it there are very few things you can not do with dials.

 

[chips&more]

The DRO set-up is one way to go. And there is also Trav-A-Dials that I personally prefer. I don’t like to watch the dancing numbers that the DRO has. I much prefer the analog dial for noting table travel. Some people can say the Trav-A-Dial has limitations but I have not been disappointed…Good Luck, Dave.

 

[EmilioG]

The DRO set-up is one way to go. And there is also Trav-A-Dials that I personally prefer. I don’t like to watch the dancing numbers that the DRO has. I much prefer the analog dial for noting table travel. Some people can say the Trav-A-Dial has limitations but I have not been disappointed…Good Luck, Dave.

Curious, what is a Trav a Dial? How does it work.
on a side note, the quill clamp, how is it used and when?
My boss tried to blame me for leaving the quill clamp open, when in reality, I don't remember using it.
Aren;t the operators of mills supposed to check all settings before using it? The Holex jumped and part got chipped a little.
Thanks

 

[JimDawson]

A Trav-A-Dial is a linear measuring device that can be attached to almost any machine tool and is used for position measurement. It is driven by a small wheel that contacts the table on a mill or the ways in the case of a lathe.




You can see the drive wheel at the top of this picture.




The quill clamp (or quill lock) locks the quill in place so it can't move.

Yes, it is the operators responsibility to check the settings prior to operating the machine.

Quill Clamp:

 

[george wilson]

A Trav a Dial is a dial indicator that has a wheel on it which bears against the table,or against the edge of the front way on a lathe. The device is most often found on a lathe. The wheel tells how many thousandths the unit has moved. It is,of course,mounted usually on the carriage of a lathe.


"Why not use dials instead of a DRO?" I had a DRO at work,but none at home. The reason dials are not as good is they depend upon the accuracy of the lead screw. The lead screw is subject to wear,just like anything mechanical. Your measurement can be off by quite a large amount if the screw is worn a lot. Years back,Bridgeport tried alternative means of accurately controlling table movement. One method was a special gage block holder mounted on the front of the mill table. Some of these gage blocks were quite long. They were laid in whatever combination needed to set the required distance. Then,the table was moved till it butted against the stack of gage blocks. This was cumbersome and everything had to be very clean between the gage block's surfaces. Then,they invented a glass scale you could read through a magnified window. This was better,but I think it was only usable on the X axis,like the gage blocks. The DRO is the best and most reliable system yet.

There is a cheap one I do not recommend. The "Shooting Star" I think it's called. It uses a small gear rack,like the rack on a dial caliper to measure table movement. It is mechanical,and I would not like to rely on it not breaking down. It is also not as accurate as a good DRO,which can get you down to .0002",or maybe even .0001". I can't recall. The Fagor at work would do .0002" resolution. It is tricky to get the table set to that fine a resolution!! Do anything at all,and the number would shift.

P.S.: I see Jim beat me on the Trav a Dial.

 

[12bolts]

...on a side note, the quill clamp, how is it used and when?
My boss tried to blame me for leaving the quill clamp open, when in reality, I don't remember using it.
Aren;t the operators of mills supposed to check all settings before using it?

Pretty much answered your own question there. Standard practice (very basic explanation) is to set up the work and tool, position the table, bring the table height up using the knee and then accurately bring the tool down to the work via the quill. If you are drilling holes you wont use the lock, if you were milling with the table travel (x & y) then use the quill lock.
Poor operator blames his tools. Poorer boss blames someone else...........thats why machinists are grumpy and usually work alone. Nobody wants to be around them!

Cheers Phil

 

[EmilioG]

Thank you Gentlemen, that is a lot of great information.
It is appreciated.

 

[Bill C.]

I just started working with an old Bridgeport milling machine and
at first it was a little daunting, but gaining more knowledge and getting more comfortable.

I don't have a manual and I'd like to know how to change
the speeds, it has belts but no speed dial. It shows a high and low speed setting
along with other RPM speeds. The BP has a break on top to keep the spindle from
moving so that you can change collets. I'll take a photo and post it but I'm sure
the vets here know what type and model this is.

I did find this> https://www.youtube.com/watch?v=xqWwDi93Esw

but it's not entirely clear and not the same machine that we have.

So I have two questions, how do I change the speeds and how do the micrometer dials work?
Are there any downloads for BP mills? pdf manuals on various models?
Thanks

Would like to add make sure either the set screw or clamping ring nut is tight so the micro-dial doesn't slip. Try not to over tighten the setscrew, you can strip out the threads. Trust me I have turn many of those dials only to get half way through the distance I needed to move to the next hole and have the them spin free on me. I like BP knee mills. I hope it serves you for many years.