I have an old M-head that lost the smoke in the 1/2HP motor. I figure since I'm buying a new motor, I might as well get as big a one as I can.

Anybody out there running 1 or 1-1/2 HP through an M-head without failures? Mine has an MT#2 spindle. I guess I'm not even sure how much torque those can handle.

TIA

Tiny spindle, small bearings, no backgear for torque multiplication, The splines are small...

3/4 hp is all Bridgeport put on later ones, The 1/2 max drill/end mill capacity really does not need more...

Not a 3 in boring bar in 5 inches of steel type of machine...

A 1 hp round ram with the bigger R8 J Head, is being pushed, pretty flexible...

You mean an R8 J-head conversion on my machine? Is someone doing this? I thought the J-heads were too heavy for my ram.

It would be very nice if I can do it.

There was an official J-head adapter made, see http://www.lathes.co.uk/bridgeport/page16.html but this doesn't allow nodding movement.
Its not too difficult to make up something from heavy plate. Picture shows the one my friend John made which fits the clevis end of the ram and works well and allows a small nodding movement via to vertical adjusting screws. Memory says John used 1/2 inch plate as he had some in stock.
Box on side is a static phase converter.

Clive

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The round ram is not very stiff with the extra power of the J Head on it..

I am running one, now.. Heavy work goes to the big cincinnati...

There were factory mills made for 3 or 4 years, with the new dovetail ram, and the upsidedown round ram bolt pattern. A bolt on upgrade, with a lot better nod clamping system.

But most of the round ram head tables are 32 or 36 in, and a table swap gets $$$ There are a few larger table late M head machines.....

Add in the slightly newer mills(also a few M Heads), with 12 in of Y travel and upgrading beyond a certain point, just does not make $$$ sense..

A real late dovetail M Head to J head would be the nicest...

I have run a J head on an m base it was a factory deal I liked it better with out the knoding feature that makes the mill so unrigid I would put a 3 phase 1 hp on the m head and put a vfd and get varispeed my m head was single phase. 1/2hp

Thanks for all the info guys. I ohmed the motor yesterday just to make sure what the previous owner told me was true. The motor tested good so I wired it up and it spins. Switch is pretty badly worn so I'm guessing that was the only problem. Anyhow, looks like I won't need a motor now.

I will keep my eye out for a J-head in the future. If the right deal comes along I may try the swap.

I have a round ram with a J head on one end of the ram and an M head on the other. Came that way, funny-looking beast. Has the "war finish" stencil on it.

I've never had the need to use the M head. I've sometimes thought about setting up a drill-press sort of table under it while keeping the J head over the milling table, but I've never needed to drill that many holes that quickly

But it shows it can be done anyways. I don't know if the round rams came in different diameters, mine seems fairly stout for what it is.

That would be a nice setup. Even though I'd probably never spin the turret to the M.

My M will have new bearings now so if I ever do come across a J, I could see them flanking each other on the ram. The M might as well collect dust and be ready to use instead of sitting in the corner.