Poorly Bridgeport.

[ukracer]

Sadly I finally managed to get a couple of days to make my steady rest for my Colchester master 2500 and my Bridgeport decides to go wrong.
Now as its the first time I have had to move the head from the vertical perhaps I have done something wrong.

However I started cutting an angle into a piece of metal to form a V opposite to the one on the bed.
I had measured it to be 50 degrees so set the head of the bridgeport to 50 degrees.
It cut just fine for about 4 passes approx 0.5mm each pass and then the cutter just stopped and the head changed noise.
I tried the slow speed lever and that still works fine but not the high speeds.

The belt is fine by the way.

Any suggestions please.

 

[ukracer]

With lever in the followiing positions this is what should happen;

Lever on top to front, lever on side of head for HI/LO to the rear, rotate pulley by hand spindle rotates in high range same direction your ro0tating pulley.
Lever on top to side, lever on side to front...rotate pulley and you get no spindle rotation
Lever on top to side, lever on side to front, rotating pulley makes spindle rotate opposite direction pulley is rotated
Lever on top to front, lever on side to front, no rotation possible spindle is locked.

For clarity it's not doing the 1st operation.

 

[ukracer]

I think this guy has the fix

but he just mentions it in passing and I don't know which screw he is on about.
Anyone know to a video that would assist?

It's about 2.30 into the video. But I have searched high and low and don't know what the screw is called.

 

[Agroshield]

Vintagemachinery.org has a whole heap of Bridgeport manuals (http://vintagemachinery.org/mfgindex/detail.aspx?id=2099&tab=3). If you know which head you have (http://www.lathes.co.uk/bridgeport/page2.html might help identify it), the exploded diagram will allow you to trace the drive path from motor to cutter and see which part is not uncooperative.

 

[ukracer]

Vintagemachinery.org has a whole heap of Bridgeport manuals (http://vintagemachinery.org/mfgindex/detail.aspx?id=2099&tab=3). If you know which head you have (http://www.lathes.co.uk/bridgeport/page2.html might help identify it), the exploded diagram will allow you to trace the drive path from motor to cutter and see which part is not uncooperative.

I watched a complete video of a rebuild and my guess is the drive dogs at the top of the quill and the bottom of the pulley are worn.
As this has only happened since I tilted the head 50 degrees I think it's caused the lack of connection.
I am going to try and find a manual now. But I am not sure I can cut with the head tilted so I might need to print a 50 degree triangle to make set up easier and cut with head in the vertical.

 

[ukracer]

Ok update: I have managed to work out what's happening and it is exacerbated/caused by tilting the head.
I am not exactly sure if the low/high speed ring at the top of the head is supposed to keep the drive from disengaging. It's doing it because of the vibration. The Bridgeport is a bit tired and possibly needs some bearings but it's done me fine so far.
I have a work around planned now which involved a strap across the ring and a bolt holding the engagement down. This will do till I get more time.

I think I need new dogs definately bottom but I guess tops as well.
It won't be cheap so it will have to wait.
Not tried it back to vertical yet but I am sure it will just drop down instead of catching on the side set at 50 degrees.

 

[ukracer]

Update.....bonus was it was 4 springs were missing from the cover. Easy to fall out so I guess it was a little knowledge is dangerous.
Replaced all 4 springs and it's working as good as it was . Oh I replaced 2 bearings while it was apart.

Just the x axis motor plastic worm pulley to replace now.
Still works but it's noisy. Only 20 quid on Amazon. But comes from China so an Xmas project I guess.

 

[Pete.]

The springs fell out of the one I had apart last weekend. I might not have spotted it except I keep my workshop fairly clean and the floor swept. I re-fitted them with a dab of heavy grease to hold them in the holes.

 

[ukracer]

The springs fell out of the one I had apart last weekend. I might not have spotted it except I keep my workshop fairly clean and the floor swept. I re-fitted them with a dab of heavy grease to hold them in the holes.

I watched a video and it all came back to me. Lol

 

[lchris21]

Whatever you do, whilst its having some TLC, make sure you check the knee gib strip is getting plenty of lube, and adjusting screw is in good condition If that fails it can right off the entire machine , hence why you sometimes see spare heads for sale and the rest of the machine becomes a boat anchor. I managed to rescue one which had suffered the gib strip screw failure, an absolute nightmare job !

 

[ukracer]

Oops never oiled it yet. is that the z axis with the winding handle that falls off.

 

[lchris21]

Oops never oiled it yet. is that the z axis with the winding handle that falls off.

yes. the retaining slot on the gib strip can shear off, or the adjusting screw can shear, especially if you have power feed. This results in the gib wedging itself in. Took me nearly a week of blood sweat and tears to get one out, machine had to be stripped to the column, x-y axis and head off, laid on its back and a hole bored through the base to knock the wedged in gib out.

grab a coffee if you want to read some horror stories https://www.practicalmachinist.com/forum/threads/advice-on-jammed-sucked-bridgeport-knee-gib.176044/

 

[ukracer]

yes. the retaining slot on the gib strip can shear off, or the adjusting screw can shear, especially if you have power feed. This results in the gib wedging itself in. Took me nearly a week of blood sweat and tears to get one out, machine had to be stripped to the column, x-y axis and head off, laid on its back and a hole bored through the base to knock the wedged in gib out.

grab a coffee if you want to read some horror stories https://www.practicalmachinist.com/forum/threads/advice-on-jammed-sucked-bridgeport-knee-gib.176044/

OMG.....please no I have enough pooh in my life just now.