Repair of Monarch Series 60/61 Saddle Using Moglice

[nt1953]

First let me say that I have quite a bit of lathe bed wear because the folks that owned the lathe before me, TVA, did not do enough maintenance on the lathe and the oil pump in the apron was not working. The wear on the carriage V-way is about .014" and on the rear flat it is about .007". I can not afford to have someone regrind the bed for me, so I have to live with what I can do myself.



This means that the V-ways are less than 90deg where the wear is greatest, and because of the wear difference between the v-way and the rear flat, the wear rotates the entire carriage down in the front where the wear is greatest. Additionally, the wear means that the bed is concave (sway backed) over part of its length (at point of maximum wear) and convex over the remainder of its length. All of these factors mean that oil will not stay under the saddle and no matter what I do the saddle will wear abnormally.

No amount of scraping of the saddle will fix the wear on the bed so I decided that I would forego scraping on all the work I did on the lathe. Even without scraping, the work I am doing on the lathe is making it better than what it was when I got it.

I am well satisfied with the Moglice. It made a nice surface and appears to be quite hard.

In the next posts, I will outline my observations, what worked for me, and my suggestions.

 

[nt1953]

Observations:

• I found that my saddle was very hard. I ruined three HSS dovetail cutters before I gave up and went to carbide. The cross slide and compound parts were not hard

• The resin is very hard, kind of like half hardened modeling clay. The resin does not conform to the can it comes in, it just sits in there like a black turd, and falls out when you upend the can.

• They say to mix the Moglice for 5 minutes. Five minutes of mixing is quite tiring because of how thick it is.

• They want you to put a layer of Moglice on the bed, and then put all of the remainder on the saddle. The material does not spread well (too thick), and it is somewhat difficult to get an even layer.

• They say to use jack screws to break the saddle free of the bed after the Moglice has cured. I used the stand off screws ( Monarch 16CY Restoration Part 8: Saddle and Way Measurements - YouTube at about 17:30) to jack the saddle from the bed. That was a mistake. The screws were surrounded by Moglice and caused corners of the Moglice under the saddle to break off. I just epoxied them back in place (one corner was about a 1/8" triangle and the other was about a 3/8" triangle). It would have been better to have used a hoist to apply some load, and then whacked the saddle with a dead blow hammer.

• They said that Moglice eats HSS and carbide tooling, and to use a cut-off wheel in a die grinder to trim the excess. I found that a cut-off wheel worked well, and I used a 1/4" carbide end mill to cut clearance for the crown of the V-way.

 

[nt1953]

What worked for me:

• I used a carbide roughing end mill for one side of the V-way (side cutting), and a cobalt regular end mill on the other side of the V-way (end cutting). I then made .050" (vertical and horizontal) cuts in the smooth surface generated by the cobalt cutter to make real sure it was rough enough to provide a good bonding surface.

• I made a cast iron piece for the rear flat and bonded it in place with high strength Loctite epoxy. I machined it after the epoxy was cured. No reason for doing the repair this way, it is just what I did.

• I did all the machining of the Moglice after casting on the mill. It worked out very nicely.

• I located all the oil holes using the DRO on the mill, took pictures of the hole angles, and recorded the hole diameters before I did any casting of Moglice.

• I used oil based modeling clay to stop up the oil holes so they would not fill with Moglice.

• I used a 1/8" stubby drill to drill the oil holes in the Moglice. I used a hand drill to finish cleaning out the holes and get the angles right.

• I could not get all the clay out of the holes with picks, drills, or air, so I used a hand operated oil pump to push the last of it out.

• I used a 1/8" burr in a Dremel to cut the oil channels. Using a template meant that I could rest the shaft of the burr on the template as I was cutting to help me get the depth correct.

 

[nt1953]

Suggestions:
• If you go with Moglice, don't forget to machine some clearance in the saddle V-way for the crown of the bed's V-way. If you do that, then when everything is done, the Moglice in the V-way is one continuous piece instead two pieces, one piece on each side of the v-way.

• Regardless of the material you choose, I would do the back flat first, machine it as required, and then do the V-way.

• To do the V-way, I backed off the inside V-way jack screws and used shims between the back of the bed and the saddle. The jack screws pull the saddle forward until stopped by the shims at the back of the saddle. These shims allow you to get the saddle aligned with the headstock. I decided to set my saddle to slant .003" to the left (front to back) over the length of the cross slide. This slant will make face cuts slightly concave. I felt it was better to be slightly concave than to be convex. I got my data about the angle on the cross slide from this video at about 19 minutes: Lathe Carriage Machining Rescue Part 1 - YouTube . I have always heard about this, but have never seen anyone else machine it that way, or give any data about how much to slant it.

• If your worm parts in the apron are tight, then you can insert a 14" long, 1.060" diameter rod (CRS) into the feed worm on the right side of the apron. If you turn about 2" the end of the rod down to 1" diameter, and everything is lined up right, when you move the carriage to the right, the simulated feed rod should slip right into the feed rod end support hole at the end of the bed (what Monarch calls the rear lead screw box). This all assumes that you have installed the apron on the saddle, and weighted the back of the saddle to prevent the lifting of the saddle because of the weight of the apron. This will ensure that the shims in between the saddle and bed are made correct for the cross slide slant, and the position of the feed rod, clutch rod, and lead screw are correct as well.

• Machining the Moglice generates a tremendous amount of noxious dust. Wear a mask and use a dust collector or vacuum cleaner.

 

[marka12161]

What worked for me:

• I made a cast iron piece for the rear flat and bonded it in place with high strength Loctite epoxy. I machined it after the epoxy was cured. No reason for doing the repair this way, it is just what I did.

This is interesting. I have significant wear on my tailstock and the popular convention is to not use Turcite as it is too slippery. The common fix is to machine and scrape the bottom of the tailstock and shim between the base and the top. I've wondered about your fix as an alternative. It would eliminate the need for shims.

 

[nt1953]

I suppose you could use cast iron strips to build up the tailstock, but I am going to shim mine. So, I have machined the tailstock base,and hope to be making some shims this week. To resolve the issue of binding on the tailtock offset adjustment screws, I turned the "grip" of the bolt down to the minor diameter of the thread so that the bolt had more slop in the hole. This will make it possible for the base and upper castings to be separated by a shim without the offset bolts binding because of misalignment. I can post a picture or two when I get my shims made.