‘39 10EE tachometer repair

Hey all I have a 1939 EE and the tachometer does not work. I pulled the lid off the headstock and verified the mechanical components are intact and working. Ruling that out I pulled the tach from the machine. I noted that the tail of the needle was missing, and that makes me suspect someone had been in here before. The needle responds to spinning the drive, but erratically and sometimes not at all, and I can hear something is not right in there. I don’t see how to take it apart, and I’m wondering if anyone here has some advice or experience that could help me disassemble the tach to inspect the internals, or that may have a lead on a replacement tachometer if this one turns out not worth fixing. Thanks
Alex.

There is a lot of info in this thread:
10ee Tachometer Disassembly

Dave,
Thank you for sharing this informative link to help figure this one out. Once I removed the needle and dial, I noticed right away that the perch with the small factory set metering screw was bent out enough to allow the spindle to drop out. How that could happen I’m not sure. I just bent it back in place with my thumb and spun it over and the spring and rotor work again. I checked the magnet and other components before I put it all together, and replaced the busted needle with a neat little red one I had on a clock that no longer worked. I made sure it was same thickness of the original, and length of the original in a photo of an original for
reference. I put it all back on the machine and fired it up. Works but I’d like to verify accuracy somehow. This machine had its Sunstrand drive removed and fitted with an older VFD and Baldor 5HP motor long before I got it, but I wonder if 1275 RPM is all it puts out now or the tach is way out of calibration. Little of both I suppose. I’ll look further into this, but thank you for the help!
Alex

Old school time: get a Starrett or any other brand of mechanical rev counter and do your own calibration. I would aim for 5% accuracy, but you could do better.

Here's one for $10:

L.S. Starrett RPM Gauge Tachometer Speed Indicator Revolution counter Athol,MA | eBay

BTW, what is the serial number of your machine and who was the original owner? You can ask Terrie to look that up if you aren't sure.

Thanks for the tip I’ll look into a few of the options out there but I do like the idea of having the “old school knowledge” in my back pocket. The Serial number is 7321, so a late December ‘39. Terrie sent me the original build info pdf and the machine was ordered to Harrison Radiator Division, General Motors Co. in Lockport New York. The pallet it was on when I bought it had a tag from a casting company in P.A. I’m in Cleveland Ohio so it seems this machine as been out near me the whole time. It now resides in my home shop where I work on old motorcycles.

Caveat for ads touting Steam Punk before more important details like, 'it works'. Any bozo who can't figure out how to test hasn't even an electric hand drill, or is well, a bozo.
Of direct contact instruments, some need to be timed, greater accuracy is attained through longer specific periods, as long within counting ability [more or less an odometer] of the instrument. Matters not 35 seconds, or 140, its derived from 60.
Timing? That funky 70's digital watch, a stop watch, analog wrist watch, a cell phone, kitchen timer......

Leadscrew69 said:

The Serial number is 7321, so a late December ‘39. Terrie sent me the original build info pdf and the machine was ordered to Harrison Radiator Division, General Motors Co. in Lockport New York. The pallet it was on when I bought it had a tag from a casting company in P.A. I’m in Cleveland Ohio so it seems this machine as been out near me the whole time. It now resides in my home shop where I work on old motorcycles.

Click to expand...

Very cool. Mine is #7552, 7/1940, so only 231 Monarch lathes were produced between. Please post some photos. The '39 lathes are quite interesting, a lot of them have some of the features shown in the patent drawings.

-Dave

rimcanyon said:

Old school time: get a Starrett or any other brand of mechanical rev counter and do your own calibration. I would aim for 5% accuracy, but you could do better.

Here's one for $10:

L.S. Starrett RPM Gauge Tachometer Speed Indicator Revolution counter Athol,MA | eBay

BTW, what is the serial number of your machine and who was the original owner? You can ask Terrie to look that up if you aren't sure.

Click to expand...

How would I be able to get Terrie to look up the original owner of my 10EE?
Sorry for the off topic reply...

Terrain2015 said:

How would I be able to get Terrie to look up the original owner of my 10EE?
Sorry for the off topic reply...

Click to expand...

Just ask her. They seem to have that info for most lathes, although there were some that were bought under secret govt contracts where that info is not available.

Terrain2015 said:

How would I be able to get Terrie to look up the original owner of my 10EE?
Sorry for the off topic reply...

Click to expand...

You call Monarch at 937 492-4111. Provide your lathe's serial number. If you ask for the build sheet and the manual for the lathe it'll cost you like $50-$60 and they'll ship it to you. The build sheet will have the dealer and the original customer at the top. If you're nice they might email you the build sheet after you place the order.