swapping heads

I've recently aquired a BP series 1 with j head and 1hp motor,the vertical gears under the front step pulley (spindle gear?) dont mesh very well, very rounded edges, very rattly when operating. Ive also got hold of another J head 1.5hp so was going to do a straight head swap. However there are some differences and I could use some advice. The new head can be rotated horizontaly but the old one cant, does this matter? I'm assuming I can split it at the mount plate just behind the spindle handle. Does the worm to rotate need to be in a specific position to remove the head? Ive attached pictures(hopefully) of each head.
Thanks, Matt

Matt,
First of all, go here and read everything. Bridgeport Milling Machines
You need to know what you are talking about to be clear to everybody.

What you show in the picture is a round ram mill with a J-head attached. The lower portion of a J head.
You say you have another J head, but 1.5 HP. AFAIK, the only 1.5 HP heads were the early variable speed 2J heads.
If you are not certain, post pictures.
JR

you have 2 things you are looking at, head and ram, heads are identical, its the ram that rotates the head. Seperate the heads from there rams, and put whatever head you want on what ever ram you want to use. $ bolts on front of head remove it from the ram.. worm gear does not matter just push it on and bolt in up

Thanks JR, I'll get reading and get some more pics uploaded to help explain myself.

Your second picture shows the J-head factory fitted to the older round-ram Bridgeport. The round ram has a solid mount for the head. The ram is rotated to tilt the head. There is no nodding ability as per later dovetail ram machines generally known as "Series 1" types. (That naming convention being retrospectively applied after the Series 2 machines were introduced.)

The first picture shows a J-head mounted via an adapter to the twin tube overarms of a horizontal mill. Various adapters were made covering a range of machines. These adapters usually included facilities for the worm and wheel used to rotate the head on dovetail ram machines as twin tube overarms, like the Series 1 dovetail ram, obviously cannot rotate themselves. The hexagon drive for the rotation worm can be clearly seen above the quill lever in your first picture. When dealing with adapters its unwise to assume that the rotation gear is all present and correct! Actually its unwise to assume proper function of the rotation worm and wheel in any Bridgeport of unknown history, especially one of significant age.

For all practical purposes all J head internals are interchangeable although its probably wise to check part numbers from manuals of appropriate years as there have been some changes over the half century or so of production. Although the basic castings are the same heads made for round ram and some adapter fitments were not machined to take the worm drive and wheel needed for independent tilt control. For all practical purposes it should be possible to bolt a complete Series 1 J-Head with tilt drive to a round ram or similar fixed adapter. Fixed adapter, non-rotating heads, may not be universally interchangeable as there can be some machining differences in fixed adapters.

Clive.

Adding some extra pictures here, sorry some arent so clear. Two show the current mill with the bad gears(and shimmed cam ring) that I want to swap the head of. This has a 1hp motor. I stole the v belt for the head i want to exchange for as this was split.
The other two photos show the new(er) head which has a 1.5hp motor and the tilt worm.

Thanks for the info Clive. So if I'm understanding you correctly there's no reason that I cant swap the heads following Sam's directions(Thanks Sam) though I'm assuming that I'll lose the tilt feature as the gears wont be present in the older machine's ram? If that is the case could I tilt the head by hand and lock it into position or does it not work that way?
Thanks, Matt.

Matt

Simple swop should go just fine. Have a careful measure up of spigot diameter and recess size. Should be a pretty close fit so you might get unlucky with tolerances all adding up the wrong way.

May need to pull the worm drive for the tilt out to ensure you have plenty of clearance for the spigot on the end of the round ram. Leave it in if you are certain there is plenty of room but you need to be sure as you can't see whats going on inside when fitting.

If you have a large collet the easiest way to handle things is to fix a vertically upright bar to the table and grab the end in the collet. Fat bar with a turned down part to grab is most secure. Then you can use the knee and table feeds to get everything lined up before easing into place. Much more civilised than slinging from a hoist or engine crane.

Clive

Thanks for the info Clive. I've already made a contraption that bolts to the table and goes in a collet as you suggested, idea stolen from here...
BRIDGEPORT MILLING MACHINE Removing the Head - YouTube

Yes, thought I might have to pull the worm and save in a secret place for better days!
Matt

Mattyboy said:

I've recently aquired a BP series 1 with j head and 1hp motor,the vertical gears under the front step pulley (spindle gear?) dont mesh very well, very rounded edges, very rattly when operating. Ive also got hold of another J head 1.5hp so was going to do a straight head swap. However there are some differences and I could use some advice. The new head can be rotated horizontaly but the old one cant, does this matter? I'm assuming I can split it at the mount plate just behind the spindle handle. Does the worm to rotate need to be in a specific position to remove the head? Ive attached pictures(hopefully) of each head.
Thanks, Matt

Click to expand...

Are you going to sell the adapter in picture #1?
If so I may be interested if it can be adapted to my mill?

Kevin

Let me see how the swap goes and i'll get back to you Kevin.