Monarch AA Tail stock refurbishment questions....

jakefreese · Mar 26, 2015

I need to refurb the tailstock on my AA.

I had seen the thread where the SB 10 was bored on the machine, this looks like a good way to go as I could get the help of one of the local guys to do the work. But I started pricing materials to do the work, and it brings up the problem of many of the pieces that are needed to do this are a one time use. Are there other ways to attack this and not have to spend a bunch on material that will only be used for the boring work only to get set on the material rack as an ornament. My other thought is send it out to a shop that can bore, sleeve, hone and get the quill ground and chromed. How would the accuracy be on a shop boring this referencing off the base of the tailstock? I just do not have the experience to be able to jump into this and get an acceptable finished piece by myself.

Thanks guys!

rimcanyon · Mar 28, 2015

There are right & wrong ways to approach this. The tail stock base should be addressed first - the ways wear in the front, and the repair is to scrape or grind the base into rough alignment, then add turcite or moglice to restore height, finish scrape to restore alignment, then bore the upper casting and make a new ram or hard chrome the old one and grind to fit.

vettebob · Mar 28, 2015

Turcite or rulon will compress when you tighten the tailstock down. Richard King informed me not to do that. This is what I did.

I made Cast iron inserts out of durabar then machined the tailstock base for the inserts. Or another option would be to grind or machine the tailstock base true the build it up by gluing bronze shim stock to the base using locktite 380 or something similar. After truing up the base I bored my tailstock on the lathe (10EE) Here are some pics Showing my setup

I bored it to 1.303 then reamed to 1.3035 and lapped using multiple brass rounds with 400 grit lapping compound to 1.304. I made a new Quill to 1.3035 and everything fits so well that I can extend the quill out 4" and have no deflection.

My total cost $150 plus 3 days work. Hope this helps Bob

pbungum · Mar 28, 2015

Vettebob - any chance you have photos of what the base looked like after machining, but before bolting in the inserts? I'm assuming that you scraped in those inserts after mounting to the tailstock - is that correct? Did you align the tailstock dead flat, or with a slight upword nosing?

Very cool job.

vettebob · Mar 29, 2015

I forgot to take pictures of the base after machining. I ground my Base parallel top to the bottom, then installed the inserts and reground the flat insert and scraped it for oil retension relieving the center 3-4 tenths. With my lathe level I then checked the base for squareness to the bed and scraped the v until it was level and the flat made contact across it's width. The pic above shows scraping in progress. When I bored the Tailstock everything needs to be level because when you push the tailstock through the fixed boring bar with the carriage the hole will be parallel to the bed. After boring You can shim to make the front high. (thin cheap aluminum foil is 0.0003 regular reynolds .0004 and heavy duty approx. 0.0005-6). When I get a chance I'll try to take some more pics. I'm replacing my AC and Furnace complete with new ducting on my house. You can read more about what I did on new to me 10EE by vettebob.

pbungum · Mar 29, 2015

Thanks Vettebob - that was very interesting!

jakefreese · Mar 30, 2015

Thanks Guys!

Bob, that answers my next question about the concerns on the bottom of the tailstock. I could see if the base has been trued back that sliding on the ways for the boring would be ok. That thread with the SB10 he had the boring bar bracket mounted to the carriage and it pulled the bar through the tailstock as his thought was having the tailstock locked down would be more accurate. I wish I could have made it to the rebuild class in Texas this spring. $150 and some work sounds good to me. I just need to figure out how much wear my machine has to see where I am going to be on the project.

vettebob said:
Turcite or rulon will compress when you tighten the tailstock down. Richard King informed me not to do that. This is what I did.
View attachment 135025I made Cast iron inserts out of durabar then machined the tailstock base for the inserts. Or another option would be to grind or machine the tailstock base true the build it up by gluing bronze shim stock to the base using locktite 380 or something similar. After truing up the base I bored my tailstock on the lathe (10EE) Here are some pics Showing my setup
View attachment 135026 View attachment 135027 View attachment 135028 I bored it to 1.303 then reamed to 1.3035 and lapped using multiple brass rounds with 400 grit lapping compound to 1.304. I made a new Quill to 1.3035 and everything fits so well that I can extend the quill out 4" and have no deflection.
View attachment 135029 My total cost $150 plus 3 days work. Hope this helps Bob

rimcanyon · Mar 30, 2015

vettebob said:
Turcite or rulon will compress when you tighten the tailstock

That may be true. Or maybe not. Do you have any hard data, e.g. mfr's info on turcite's compressive strength or cold flow to support your assertion?

Turcite is often used to restore geometry even in situations where the load is uneven (such as a horizontal slideway for a vertical head, where most of the weight is in front). If there were issues with compressive strength or cold flow, it would show up quickly. It doesn't, even though the point loading is higher than for a tailstock.

PDW · Mar 30, 2015

rimcanyon said:
That may be true. Or maybe not. Do you have any hard data, e.g. mfr's info on turcite's compressive strength or cold flow to support your assertion?

Turcite is often used to restore geometry even in situations where the load is uneven (such as a horizontal slideway for a vertical head, where most of the weight is in front). If there were issues with compressive strength or cold flow, it would show up quickly. It doesn't, even though the point loading is higher than for a tailstock.

I was told (or read somewhere) that a reason not to use turcite or similar on a TS was it was too slippery, and the TS would back up under heavy drilling operations.

As I've never done it, I have no idea if this is correct, but it makes some intuitive sense. Which generally means, it's myth.....

PDW

vettebob · Mar 30, 2015

Per Turcite spec sheet It has a shore D durometer of 50-60 per astm D2240 used to measure the hardness of rubbers and plastics. Or in simple terms about the hardness of a hard rubber o-ring. It will compress and depending on where the clamping force is applied (my 10EE tailstock applies force to the front) will cause the tailstock to dive either in the front or back when clamped down. Of course how much it will move depends on thickness of the turcite and amount of clamping force applied. I trust in the years of experience Richard King has on this matter and reading up on the technical specs just reconfirms it is not the best material for a tailstock. Bob I'm trying to be helpful here I'm now done with this conversation.

Richard King · Mar 31, 2015

Bob is correct. Machine builders do not put turcite B or Rulon 142. I use Rulon 142, on the bottoms of tail-stocks as it can sqwish when tightened. If you want more information on the technical side of the materials contact Richard Cedrone of Tri- Star plastics, [email protected] their website is Tstar.com

I am so proud of what Bob did to his machine as he hosted the KC scraping and rebuilding class we had last Fall. Scroll down to # 34 of the thread. http://www.practicalmachinist.com/v...ng-class-anyone-interested-283902/index2.html

Pus I love the way he is teaching what I Taught him, plus using his own good ideas!! Great work BOB! Rich

rimcanyon · Mar 31, 2015

The simplest solution is to scrape the bottom of the tailstock then shim between top and bottom to restore geometry.

jakefreese · Mar 31, 2015

rimcanyon said:
The simplest solution is to scrape the bottom of the tailstock then shim between top and bottom to restore geometry.

It is sounding more and more like I need to learn to scrape. I probably need to hit Richard up on a set of videos.

Scrape it, shim it, bore it, sleeve it, grind the quill, bore it, hone it.....???

Richard King · Mar 31, 2015

What Bob did was what a professional rebuilder does. If we shimmed a rebuild, we would get fired. If your looking at a Great machine rebuild it, if you want a good enough machine shim it.

jakefreese · Mar 31, 2015

I want it to be right, I like this machine I got it from someone who spent a lot of time fixing many things on it and took a lot of pride in the machine, I want to take care of it. This is my I don't want to half ass it, if spending some more time and some more money on it makes it better over acceptable then I will it is not like I have to have the machine running to put food on the table.

So building it up with durabar, and scrape back it the preferred method to get the job done I will go that route. I think I need to get a scraper and some durabar to practice on. I need to keep my eyes out for a small surface plate and a buy or build a hand scraper.

Richard King said:
What Bob did was what a professional rebuilder does. If we shimmed a rebuild, we would get fired. If your looking at a Great machine rebuild it, if you want a good enough machine shim it.

pbungum · Apr 1, 2015

Richard King said:
What Bob did was what a professional rebuilder does. If we shimmed a rebuild, we would get fired. If your looking at a Great machine rebuild it, if you want a good enough machine shim it.

Out of curiosity, why would one of these methods be "better" than the other? In one instance, you are significantly altering the casting by performing multiple machining operations (milling, grinding, drilling, bolting in inserts, grinding, scraping to align, then boring, etc.). In the other, you are scraping the bottom for alignment and maybe the top of the base for flatness, then adding a shim material of somesort, and preserving the rest of the tailstock.

I can see merits to both methods, but why would a rebuilder be fired for one vs. the other? Does it have to do with perceived "rightness", or is there an actual benefit to the more... highly modified process? This isn't a judgmental question - rather a substantive or "real" question to which I do not know the answer.

My assumption is that a good rebuild would restore geometry and accuracy, improve upon known basic flaws in a design (when possible), and alter the minimum number of parts from stock form (just those necessary). Perhaps this assumption is wrong.

jakefreese · Apr 1, 2015

Bob,

What material did you build your new quill out of?

vettebob · Apr 1, 2015

I built my quill out of 4140.

Richard King · Apr 1, 2015

There are several ways to bring back the accuracy or axis of the centerline. I believe I told Bob to scrape down the head or add a Phenolic shim or Dura-bar between the 2 - 1/2's and he picked the inserts under it. Have to ask him who or where he came up with the idea. I may have told that too....just can't exactly recall now as i talk to a lot of people. His work was a very professional job as I said before. I was kidding a bit when I said I would fire someone, But using a loose brass shim stock in the middle is not something a Professional rebuilder would do. Bob did a complete rebuild. Not a repair. I once worked with a guy named Bill Tracy who was a machine builder with Fellows and he specialized with gear testers. He told me you can use a shim to calculate how much needs to be scraped off the opposite side, but never use shim-stock on rebuilds that are left in the machine.

It's something that I try to teach my students and impart to others who read my advise. You can put a shim in there if you want. It's a free country.

pbungum · Apr 1, 2015

Richard King said:
You can put a shim in there if you want. It's a free country.

That's what they tell us... but I'm not so sure...

Thanks for the explanation. I asked as a point of discourse - not to state that I had a reason to think that the inserts were a method that was inferior to any other. For the record, I think that VetteBob's solution is fantastic, and would appear to indicate a well-planned procedure.

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