New to me Covell 14 Comparator- What have I gotten myself into

[silverforgestudio]

OK guys- Stumbled on to a FB Marketplace item- it led me to a sale at the old "Arrow Tool and Die Company" outside Philly... Guy there has already sold the building, and is having a bit of a "Fire sale" on remaining items- I bought some drills and micrometers... Went into the Quality control room and there sat a Covell 14 comparator- with a few extra lenses and plates. Machine powered up fine... Ive always wanted one- even though I cant USE one (Im still new in the grand scheme of making chips...)

Anyway- machine is home... I feel like I got a steal on it- and for it to sit, I figure I will have time to learn it...

My questions are:
1- I eventually want to make clock gearing and watch gears and smaller parts- Did I just go "WAY OVERBOARD" for this?
2- Any recommended old school texts or books on the care and feeding of these beasties?

Yes, I run the "Orphanage for Old Iron and Home-Shop Misfit Tools" If you have to ask...

Pics to follow

 

[benmychree]

Should be nearly totally useless.

 

[T Bredehoft]

You'll be able to see every flaw in your gearing. Or, conversely, how perfect you got it.

 

[Bob Korves]

Sure beats squinting at little parts or using a magnifying glass, just have to have the extra money and a place to put the thing....

 

[pstemari]

If you want to gauge all of the features on an external thread, not just pitch, pitch diameter, and major diameter, it's the way to go. You should be able to measure the flank angles, minor diameter, root size/radius, and even how straight the flanks are.

Not really needed for hobbyist use, but if you're trying to see how perfectly you can make a thread, that's the way to do it.

Sent from my Pixel XL using Tapatalk

 

[silverforgestudio]

Should be nearly totally useless.

Dude- you dont know me- I dont know you. You have some interesting content but generally are a crusty one liner guy- teach or help or pass the thread over. You are a spirit killer for new guys and toxic.

Im not a machinist- I am a hobby guy. But I am taking my hobby to the level of second income. That is why I am here. To learn.

You'll be able to see every flaw in your gearing. Or, conversely, how perfect you got it.

Thanks T- Im really hoping it helps with taking apart some older clocks so I can make accurate drawings to work to. Plus As I can mathematically know the "original" pitch diameters of the gear train- I can see how much the clocks have worn over the years.

Sure beats squinting at little parts or using a magnifying glass, just have to have the extra money and a place to put the thing....

As always- sage and true Bob! I had to move a few things and re-arrange the "grinder room" wall- but the thing is IN place and hopefully she will be at home for awhile! I work out of a small garage- space is TOTALLY at a premium... but for the price- I couldnt pass it up!

What is funny is I had been lamenting my passing on the purchase of a JnL "Benchtop" last year- I went to the going out of business sale for an item TOTALLY unrelated to the Comparator. The fellow literally said "Make me an offer"... I did and I apologized and openly told him I know its way too low- and he said "Sold...." and I looked at my buddy who came with me and asked "How are we going to get this thing OUT of the truck when we get home?"

We managed with only one injury to the Comparator (see photos) that will be on the "learn as you go" process. (The X-Y table came apart)

If you want to gauge all of the features on an external thread, not just pitch, pitch diameter, and major diameter, it's the way to go. You should be able to measure the flank angles, minor diameter, root size/radius, and even how straight the flanks are.
Not really needed for hobbyist use, but if you're trying to see how perfectly you can make a thread, that's the way to do it.

Thanks PST- You are totally right- it is a bit overkill but for the clock gearing and rebuilds of fine geartrains (where I hope to be in the future) I am hoping this will assist me in specs for original sizes and to show the flanks and angles too. Plus the ability to compare my "Shop-made" parts to "Original" specs will allow me to have a bit of self-teaching in the shop.

At least I can see how flawed my own work is! HA!

Thanks folks- now on with the show

 

[silverforgestudio]

OK so I made one horrible discovery today- 1960s era frosted glass plates are NOT etched- they are INKED... the plates for the comparator had been stored for years in a shipping box with straw and were filthy to touch... I went and got my lens cleaner I use for the microscopes and camera lenses and wiped down the first plate- and no problem... Figured this was the SAFEST cleaner I had- its designed to not remove the AR (anti-reflective) and other coatings on the microscope lenses and the photo optics.

Plate one- CLEAN! I was happy to see years of grit/grime and crud melting off the glass...

The SECOND plate however... CARNAGE! The degree lines dissolved and the lint free lab-wipe went from sooty black to a pale blue with the ink... AAARGH!

So I have ONE plate that is clear of any printed lines but is totally clean and use-able! When I saw the lines gone- I just kept on wiping- cleaning up the murder scene till it was nice and fresh... no fingerprints... nothing to see here....

No other plates were harmed in the making of this post! HA! all received a thorough dusting and brush down with a light water spritz and sponge. I cleaned out the box and lined it with flanel and bubble wrap- each plate has its own layer of insulation and will live there till I have better storage for them.

 

[silverforgestudio]

So pictures were promised a WEEK ago- c'mon slacker- where are they!???

OK... OK... OK... So here they go.

So it was bought and delivered in March 1960... I love having the "Original" paperwork- Just me? Maybe- but I enjoy knowing a tool's history.

 

[silverforgestudio]

Here she is- I cut the Plywood face to cover her until I can get the interior cleaned to keep stuff from the mirror.

Talk about tool-room porn... Shes got no DRAWERS on!

Her drawer is removed and was undergoing a bit of an industrial clean... it was full of grit, grime, spooge, smut, (insert any word for machine-shop detritus here)...

So fear not- she has her drawers back on guys and is in a decent state after this pic was taken.



Here is the Mirror and Light assembly. The Mirror has a few dots and smudges on it so I will be researching how to clean these- This is not just a plain glass mirror- the underlay glass is as close to "optically flat" and abberant free as they could get- and these mirrirs (as far as my reading/research suggests) were mercury-silvered so very high index of refraction.


So I have 4 different plates and measuring screens- the mounting ring is in good condition and there are about 50 mylar "blanks" to overlay/write on or print or trace profiles to measure to.

Outside the one "casualty" to the cleaning fluid- all is good! Spare bulbs are a plus too!

 

[Boswell]

While I don't know, I would suspect that the mirror is a front surface mirror where there reflective coating (Silver?) is laid down on the front surface of the glass. household mirrors it is on the backside and so the glass protects the mirroring surface. A front surface mirror is very easy to damage.