Model AA Project

TimRD · Sep 15, 2015

I recently got a Model AA Monarch manufactured ca. 1928 (Thanks John Oder)and I am going through it now to check it over before I put her into service.

I started a thread related to finding out the age of the lathe and the partial tear down of the machine:

http://www.practicalmachinist.com/vb/monarch-lathes/monarch-aa-lathe-manufacturing-date-308540/

I will post some pictures of my progress as I go. I have now taken the carriage off and I'm in the process of trying to get 90 years of crud off of the machine. I have a few repairs and bent handles to fix off of the bat.

Any recommendations on how to make new way wipers? The originals are brass flats with small slotted tabs to permit adjustment on the ways. I broke one off taking the carriage off, but I would prefer to make all new ones. Thanks in advance for the help and I will get a few pictures up today.

TimRD · Sep 15, 2015

Here are a few pictures of the wiper here. The screw in the bottom of the frame is the mount for the wiper. I broke off the tab that makes the slot to allow the adjustment of the height of the wiper. The one shown is not the broken wiper. It looked like there was felt inset into the bottom of the wiper, but it was mostly worn away.

Any recommendations on how to fix the broken tab? If I can locate the tab on the floor of the garage I might be able to braze it back on, but due to the size it might be difficult. Thanks in advance.

Tim

TimRD · Sep 22, 2015

I have stripped the lathed down to all but separating the base and chip pan from the the ways and headstock. I have noticed in preliminary scraping some of the loose gray paint(3 coats, and some green under that) on the lathe that it appears to have black as the base coat.

Would the original color of this lathe have been black?

jakefreese · Sep 22, 2015

TimRD said:
I have stripped the lathed down to all but separating the base and chip pan from the the ways and headstock. I have noticed in preliminary scraping some of the loose gray paint(3 coats, and some green under that) on the lathe that it appears to have black as the base coat.

Would the original color of this lathe have been black?

I don't know what the original color is, my tail stock (only thing with paint on it) is grey all the way down.

TimRD · Sep 22, 2015

Interesting, maybe the spot I was looking in was the bare before the black was applied. I will have to check a few other areas tonight.

jlegge · Oct 3, 2015

I would put the age more in the 1926-7 period. By 1928 almost all geared heads had Timken bearings in them, and Monarch was advertising their lathes as the "all Timkenized lathe"

TimRD · Oct 5, 2015

I am going to do my best to get the headstock off tonight, along with the feed change gearing. I was kicking around the idea of converting it to ball bearings, but I don't have the ability/capacity to do it myself.

What would be a rough estimate to do this if someone could put a number to it. I would be looking more for a shop to do the boring work on the headstock, but I could do the rest of the work myself. Thanks in advance.

johnoder · Oct 7, 2015

The idea usually turns out to be impractical, regardless of money considerations.

The iron isn't there - casting was not designed to accommodate the large bores required by anti-friction bearings

The cap bolts are in the way of making the bores larger

The replacement bearings have to have at least the load capacity of the plain bearings

Whatever bearings are used have to be at least as precise as well fitted plain bearings. Monarch was using precision class Timken bearings from the outset.

Ignoring such results in a speedy spindle that runs out more than the original plain bearing spindle

Scans below - big one shows Timken classes, little one shows Assembled Radial Runout. Note that the lowest precision class, class 3, has one fifth the run out of the next lower class. You can be sure Monarch was using Class 3 as a minimum. Many machine tool spindles are Class 0.

TimRD said:
I am going to do my best to get the headstock off tonight, along with the feed change gearing. I was kicking around the idea of converting it to ball bearings, but I don't have the ability/capacity to do it myself.

What would be a rough estimate to do this if someone could put a number to it. I would be looking more for a shop to do the boring work on the headstock, but I could do the rest of the work myself. Thanks in advance.

TimRD · Oct 26, 2015

John,

Thanks for the enlightenment. Makes sense looking at the headstock and the caps for the plain bearings.

I have a ton of other work to do too. I did notice one chipped tooth in the headstock. It's on the center smaller gear on the intermediate shaft of the headstock as highlighted below. I assume the best course of action is to pursue getting a new one made or contacting Monarch to see if they can even get me one?

johnoder · Oct 26, 2015

If "chipped" means the tooth is MOSTLY there, I'd run it.

If it has deformed metal that makes the pair hard to turn past that point, some judicial die grinding may help

If it makes big clunking noise running or the tooth is MOSTLY gone, then I would talk to Monarch. You have to understand that any new gear in there is going to be likely at least $1000 - they are very high class heat treated helical gears, not something approximated on a Universal milling machine

Might be a better use of such amounts to just get a better lathe

TimRD said:
John,

Thanks for the enlightenment. Makes sense looking at the headstock and the caps for the plain bearings.

I have a ton of other work to do too. I did notice one chipped tooth in the headstock. It's on the center smaller gear on the intermediate shaft of the headstock as highlighted below. I assume the best course of action is to pursue getting a new one made or contacting Monarch to see if they can even get me one?

View attachment 152577

TimRD · Oct 26, 2015

If I am remembering correctly the tooth is for the most part missing. I can get a better image of it tonight. I didn't ever notice it as I can easily turn the input shaft passed the point of the chipped tooth. I didn't see any other chipped teeth or dingers on the gear that it meshes with either. I will do my best to get some measurements of what's left versus what should be there too. Can't hurt to hit it with the die grinder after I take some measurements.

I bought the lathe while it wasn't under power so I can't speak to the clunking noises yet. I have been reading on past posts from others who have bought gears from Monarch and saw that they cost quite a bit more than I paid for this lathe (and what it's probably actually worth) unfortunately. As you have said, they are a very high class item. The ways, and for the most part the whole lathe is in pretty good shape (except this gear), but if push comes to shove it may not realistically be worth putting the money into it.

johnoder said:
If "chipped" means the tooth is MOSTLY there, I'd run it.

If it has deformed metal that makes the pair hard to turn past that point, some judicial die grinding may help

If it makes big clunking noise running or the tooth is MOSTLY gone, then I would talk to Monarch. You have to understand that any new gear in there is going to be likely at least $1000 - they are very high class heat treated helical gears, not something approximated on a Universal milling machine

Might be a better use of such amounts to just get a better lathe

TimRD · Oct 26, 2015

Okay, got a couple of pictures. Had a little plumbing emergency to take care of so it's later than I expected to get to this.

The pictures below show the chipped tooth. It is about half missing, and broken off down to the root diameter. Let me know what you think. Thanks in advance.

I will be sure to look for it in the bottom of the headstock while I have everything out too.

alskdjfhg · Oct 26, 2015

I'm no expert, but I'd just run it.

Fixing it properly would pretty much certainly cost more than what the old girl is worth.

Just go easy when your in that speed range.

Garwood · Oct 26, 2015

Run the gear as it is.

TimRD · Oct 27, 2015

Thanks everyone. I am just going to run it as is whenever I

TimRD · Oct 27, 2015

get it all put back together. Now to tear the headstock apart!

TimRD · Oct 27, 2015

Pulled the spindle tonight. Took a few pictures of the bearings. They all seem to be in pretty good shape, but let me know if you see anything that should be looked in to. The spindle is in really good shape too with no signs of obvious wear. I will put the mic to it tomorrow to check it out.

TimRD · Oct 28, 2015

Has anyone had the pleasure of removing the input clutch from the end of the input shaft to the headstock?

I have attached a catalog page showing the clutch. I can see the adjusting "nut" or more a sleeve that you tighten to control the engagement of the clutch, but I don't want to damage anything.

If anyone can offer me guidance on how to proceed I would appreciate it. If I need to get that nut loose and unthread it and that will give me more access to get it off the input shaft that would be ideal, but I don't know if that will be the case.

TimRD

TimRD · Nov 10, 2015

Update: Got the clutch off of the input shaft with a little effort.

I got most of the headstock gearing removed and when I went to loosen a nut that holds a support bearing onto the input shaft and noticed it was cross-threaded. It appears that the nut must have backed off at some point and ended up grinding into one of the gears in the headstock. The threads appear to be good on the input shaft, but the nut is pretty much trashed. I was planning on using 4140 or something similar for the new nut. Some pictures of everything below:

jeep534 · Apr 6, 2016

Tim Do you have any updates

archie

Model AA Project

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Hot Rolled

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