Macgregor Gourlay lathe rebuild questions

[mega arc 5040dd]

Hi,

I am currently rebuilding/restoring a Macgregor Gourlay lathe. At least im about 90% sure thats what it is. I have a couple questions more so about antique lathes in general.

1) What RPM range should it be? The counter shaft and head stock have 4 flat belt pulleys. There sizes are 8.5", 6.75", 5", 3.375". The back gears have 80 teeth and 30 teeth. the head stock has brass bearings. Or are they called bushings? The swing is 16" and it is a very heavy rigid machine. I have 2 motors to choose from. 3/4hp 1725 rpm or 5hp 3450 rpm. I know if I use the 3450 rpm then I will need to slow it down with a reduction through a jack shaft and thats ok there is room for that.
Will i loose any power or torque by running the faster motor and using a jack shaft to reduce the speed? What rpm range should I be trying to achieve for this type and size of lathe?

2) The cross feed nut threads are or were originally poured babbitt. The worn out threads have pulled free of the nut body and need to be repoured. I am confident that I can do this but I dont have a clue what I need for babbitt or where to get it from. All I know about babbitt is its expensive. I have a friend who casts his own bullets and he calls the left over stuff thats not lead babbitt. I believe its a mix of zink and who knows what. I'm guessing it won't work for my needs? I don't want to spend a fortune on this and its just for use in my home hobby shop. What are my options? I was going to turn a new nut but its square cut threads not acme and its pretty small diameter I think about 1/2". Thats a little small to try and cut square threads with a tiny boaring bar or at least for my experience level it is so I would rather pour it.

 

[rusty old tools]

Not familiar with that paticular brand but a lathe of that size and age would have had about 500rpm or so max speed running in open belt, countershaft speed would be in the area of around 200rpm, 3/4hp is weak for a lathe that size, most machines of that era and size would be rated around 2-3hp, that's Lineshaft horsepower so 5hp is about right on, your pulley sizes getting the countershaft turning at an appropriate speed from that 3400 rpm motor are going to be disproportionate, you don't want more than 50% difference in the diameters of your pulleys as a general rule to get the best hp transmission across the belts, we're talking flat belt, you can get away with more using v belts or serpentine, however it's my opinion that you should use a chain drive or gear reducer from the motor to bring it in to a range that will work to then belt to the countershaft with not more than 50% difference in the pulley diameters. Here's a handy pulley calculator that I use, add the thickness of the belt to the diameters of the pulleys in your calculations which will give you a more accurate result. Pulley size and RPM

 

[twagler]

Congratulations on owning a MacGregor-Gourlay lathe. There is probably only about 2 or 3 of these in running condition left in Canada (and probably none at all in the USA). The MacGregor-Gourlay name dates it to being from prior to 1910, so your lathe could well be 110 years old. I'm assuming that you've read the thread on this forum dedicated to this manufacturer http://www.practicalmachinist.com/vb/antique-machinery-and-history/macgregor-gourlay-lathes-215881/?highlight=gourlay

I purchased one last year for $200 with good intentions of fixing it up, but it turned out to be a bit too much of a basket case to bring back to life. Does yours look similar to this?



If so, I could take apart the cross-slide and see if the threaded nut is in decent shape. I would be happy to pass on any parts that would be of use to you from this lathe, rather than seeing them go to scrap. For example, here are pictures of the threading half-nut (babitt poured) which still seems in decent shape.


Regards,
Tom

 

[mega arc 5040dd]

The compound and the tail stock look identical to mine. The apron looks similar but mine has a few more nobs on it.

On mine the cross feed nut bolts to the side of the crossed. FrI'm what I have pieced together it was to make it easy and accessible to unbilt it from the cross slide in order to remove the cross slide easily found use the carriage for boring. My car age has 4 tee slots for bolting down parts for boring. Is your the same?

There was another lathe similar to mine for dale a few weeks ago. It was a CMC so a little newer but some parts look the same.

 

[mega arc 5040dd]

Can anyone offer any advise on what type of babbitt I would need to pour new crossed nut?

 

[twagler]

Can anyone offer any advise on what type of babbitt I would need to pour new crossed nut?

There is some discussion of this very topic in a previous thread. Try reading this link for some advice:
http://www.practicalmachinist.com/vb/general-archive/how-about-babbit-cross-feed-nut-90304/
To be honest, I wouldn't worry too much about the type of Babbitt material, the main difference is that some are high in lead and others are high in tin. I think either would work fine.

By the way, I checked out the cross-feed parts from my old MacGregor-Gourley, and they appear to be completely different than your's. See picture below. The cross-feed nut from my lathe appears to be solid bronze without any Babbitt whatsoever. I wondering if your lathe was rebuilt at some point where there drilled out the original threads and poured in Babbitt instead. Anyway, let me know if you need any other parts (change gears, handles, knobs, etc) that might happen to fit your machine.

Regards,
Tom

 

[mega arc 5040dd]

In the last picture is the the carrage lock on the underside? How does that work? Mine is missing all that mechanism except for the handle on the front of the apron. It has a shafts wit an off cetera lobe machined into the end. I'm assuming you would turn the lever a bit and it would pull the flat bar tight to the bOttoman of the ways.

I will try and post a picture of the front off my approx and the piece that I have.

 

[mega arc 5040dd]

The curved lever I believe is supposed to engage into something similar to the last picture of post #6.

 

[mega arc 5040dd]

I believe the babbitt crossfeed nut is original. The half nut threads are also made of babbitt and I'm pretty sure they are originall too.

Does anyone know where I can get babbitt? I'm assuming lead wheel weights won't work do to the lack of tin? Or does it not really matter since it's not a bearing?

 

[enginebill]

Lead would be too soft. You can get Babbitt from McMaster-Carr or Ebay or look in scrap yards for old bearings from machines that you can melt out the old Babbitt and re-use.

 

[rusty old tools]

I cast bullets from wheel weights, actually has quite a bit of tin, we call it hard lead, I imagine wheel weights would make some ok Babbitt, but probably better off to buy a bar from McMaster, if it were me I'd go ahead and use the wheel weight mixed with the old Babbitt and see how it goes, worst case you will need to pour it again in the future.