04-15-2011, 04:51 AM
Thanks for the feedback and encouragement. I'll limit the camera phone pics to times when detail is not important and my wife is thinking that the good camera belongs to her . . .
05-06-2011, 02:50 PM
Tracing handles . . .
The next main task for me is to fit the spindle sleeve to its bearings, but I got distracted:
In order to make missing handles for the capstan and back-gear shifter lever I had to get my True-Trace hydraulic tracer on-line. This involved making up all new hoses and getting things fitted up. I then had to re-adapt it to my 16" South Bend lathe. (I also cleaned out the sump in the hydraulic power supply.) I was very pleased to fire it up and have it work just fine with no leaks at all. I spent some time getting used to it, making a scrap handle from my sheet metal template. Once I got going, I could crank one out in less than an hour. I should be able to beat this time by quite a bit on more rigid parts (see below).
I will be painting the hub & arms of the capstan black (one edit: maybe not, the originals were bright finish. I may just make three more replica arms.) The handle pattern was made from the handle at the bottom of the picture, which is from one of the two shifter levers on the main drive transmission -- I hope Jeff still has the other. The original handles were steel and suffered from the weather -- it took quite a bit of filing and polishing to make them nice, but I feel that a major point in restoring a machine that will be run is to give the operator something nice to put his hands on.
(I note some interesting artifacts in the handles that are at a 45-degree angle in the above pic. Actually they all look the same as the vertical one.)
P.S.: I learned some things making these handles. All four original handles were missing as well as one of the levers. I made one replica lever and made the handles with the same 5/16-18 thread as the originals. This lack of rigidity made the tracing operation very time consuming even though I used a center to support the outboard end -- this can be done with the tracing setup, but it is awkward and does not allow tracing to the center. I had the extra task of removing the "nub" and finishing the ends by hand as well. If I had to do it all over again, I would make the handles and levers in one piece and save a lot of time. So much for making things "original". Lucas did it this way because they bought the handles -- I did not have to . . .
Last edited by Archie Cheda; 05-06-2011 at 08:02 PM.
Reason: Add info . . .
05-07-2011, 01:41 PM
Now, that's better . . .
I decided to turn all the rust pitting and dings off the levers -- I enjoy polishing more than painting . . . The levers are a little undersize, but the Lucas has power feed, so no one should be using the "armstrong" method. The little capstan binds down a cast iron cone clutch that engages the spindle's power feed.
Now I should get back to work on fitting the spindle bearings.
P.S.: The corruption in the previous pic was from too much compression -- I'm trying to keep these pics loading in a reasonable time.
05-21-2011, 07:58 PM
Red-letter day . . .
I had a very productive day at Tuckahoe -- I got the Lucas' saddle and table gibs fitted and then installed the saddle on the bed and the table on the saddle. I am hoping that neither will have to be removed again. (I also took a turn at grounds duty and felled a dead tree that was threatening the Machine Shop Museum building. Thanks to Jeff_G's pickup (& a rope) we got it to fall away from the building as I cut it with my electric chainsaw.)
First I had to fit the table gib plates -- all these gibs I worked on today are much like the gib plate on the back of a lathe saddle. They have a running clearance around .001" or less and serve to keep the moving member from lifting off the ways it rides on. On the table it really gives stability when the table is at the end of its travel and over-hangs the saddle upper ways by some 22" (!) -- there is still 26" of the 48" table on the saddle, but that still is a lot of cast iron hanging out there. I had planed the table's lower surfaces and expected I might have to shim the gib plates, but I ended up with a clearance of less than .001" near all bolts when tightened except for two. These two run allow free movement when they are snug, but not tight, so I think I will just put them together with locktight so they will not drift loose. (The socket head setscrew and nut I am using are just an expedient to hasten the process of testing each bolt position. The original bolts will be used for the final installation.)
Although I could use my depth micrometer, it's base was just barely wide enough, so I switched to a stack of gage blocks exactly the thickness of the bed ways. Then I bridged the gib clamping surfaces with my straight edge and could use a feeler gage to survey the situation. I had a pretty uniform .011" to remove from these surfaces. The actual area of contact is pretty small because of the relief planed in the middle of these surfaces. I presume that Lucas did this to make any hand fitting easy. On the table I had to plane below the relieved surface and decided to not plane in the reliefs -- this worked out fine. The amount of material to be removed was only .011" on the saddle, so there was at least .012" of relief left when I finished fitting.
In the pic below I am trying to show that the entire gib clamping surface is relieved in the center of the front of the saddle. This allows this bolt to be used to clamp up the saddle firmly to the bed during machining operations. The cast iron gib plate is some 3/4" thick, so it is hard to imagine it moving much when clamped up over the unsupported 5" area, but it only has to bend .001" to clamp.
During the scraping/filing of the surfaces to remove the necessary .011" I switched to using the depth micrometer bridging across the relieved area. (The circled numbers are the original dimension and those not circled were the result after each pass.) This was to aide my efforts to "scrape straight down". I found that rough-scraping the entire area followed by flat-filing with a coarse file would remove about .001" per pass. Once I had about .007" removed, I inked up the straight edge and started printing, alternating between bridging the two areas and placing the straight edge along each of the two gib clamping surfaces. At this stage I only scraped the ink marks, but continued flat-filing the whole surface.
Some may wonder why I did not use the planer. If I used the planer to remove the .011", I would not have been able to plane along the lengths of the gib clamping surfaces because the saddle was too wide to pass between the standards of the planer. I could have set it up the other way, but then I would have had two-foot long strokes cutting four 1/8" wide cuts and a lot of air in between. It would have taken longer than the two hours that the scraping/filing did and I still would have probably had to do some hand fitting. (Much experience has also taught me that when you only have a little to remove on a big machine, you often remove too much before you know it . . .)
The final result:
With the ways oiled, the whole 800# of saddle and table still glide along the bed ways as easily as the 300# saddle did by itself, but it takes a pretty good shove to break it loose from static and to get it to "surf" on the oil. The table also moves nicely along the top ways of the saddle. Next week I'll get the gibs bolted up for the final time.
Last edited by Archie Cheda; 05-22-2011 at 10:16 AM.
Reason: grammar . . .
05-21-2011, 11:38 PM
Looking over your work for the bevel gears, you have an interesting idea of CNCing them on a mill. To make all the teeth with the same toolpath I would cut them on a rotary axis, even an M-code indexer. Perform a series of cuts and then index do the same series for all the teeth. Then all the teeth are cut with exactly the same cutter profile. You can get into some amazing gotchas with CNC's trying to do something like this on a non rotary axis you can wind up with 25 teeth that have different contact patterns after lapping and will run quietly only when meshed the same as they were lapped.
PM me if I don't make sense, I got up a couple of hours after I read your posts to type this. I repair CNC's, I cut gears, and I can see the potential for problems with the method you have proposed.
The #2 BC hobber is from me.
05-22-2011, 08:11 AM
How many ways to NC a cat . . .
Thanks for your interest and inputs. Actually, RevetsP has volunteered to generate the NC paths and cut the gear, so I ask that he consider your inputs as he plans out his approach. He is doing this as a learning exercise and any helpful suggestions anyone can give him would be fine. The lead time for this gear pair is almost a year, so we have "time to learn". While I am prepared to use conventionally-generated miter gears, I find the prospect of using 21st century technology to make repair parts for this old machine interesting.
My role in the fabrication of this gear pair is to define the requirements. I am not changing the size (5" outside pitch diameter), diametral pitch (9 DP), and simple straight teeth. I did change the pressure angle to 22.5- or 25-degrees to avoid undercutting that could not be generated by use of NC. I suggested using simple 3-axis NC because I did not know what resources are available, but RevetsP wanted to use a 4th axis if he can get access to one. In many cases, the 4th axis would have to be mounted on a wedge to give a 45-degree orientation from the spindle axis. The software (& how it is used) will determine the actual tool paths, so I think any pattern of fluting on the involute surfaces could be created with or without a 4th axis. The ball end mill's hemispherical cutting surface would create the fluting and having things oriented differently would not seem to change the end result. The biggest advantage I see for using the 4th axis is that the amount of overhang of the end mill could be minimized -- this is a big deal with the small size of end mill required to get to the roots of the gear teeth and would allow a much larger chip load and hence, a greatly reduced cutting time. I strongly support his approach if a suitable 4th axis machine is available.
While I agree that the gears might not mesh properly if they are not assembled in the same way as lapped, the solution is simple: I will be doing both the lapping & assembly and it is very simple to mark the gear teeth before lapping and then to assemble them in the same mesh. Thanks for reminding me to do this.
You mention cutter profile, so please let me know if I am wrong, but I up until now I was assuming use of a ball end mill for all cutting, no matter what orientation the gear blank axis has. I can imagine side-milling rather than end milling and it would greatly reduce the fluting, resulting in flats rather than flutes. I would say that, at least theoretically, the end result would be similar to a generated gear using a cutter with rack-type profile (i.e.: a straight line). On the other hand the Fellows-type generation uses a convex cutter . . .
In conclusion, I know that there is a lot of interesting esoterica, so I have started a new thread in the CNC forum for this kind of discussion and ask that everyone limit posting in this thread to things that will directly support RevetsP's work on the Lucas gears.
05-22-2011, 09:36 AM
She looks great with the table and tailstock on! Cant wait for the pics of the column install. Thanks for sharing Archie.
05-22-2011, 01:00 PM
One only needs a 3 axis mill and an Mcode indexer, or even an old Haas with an external switch that you can mount the switch on the table, stop the spindle and push the button with the spindle tool. (who needs to have a button pusher operator when you can teach the machine to push it's own buttons!) You will be cutting a convex surface with a convex ball end mill so there will be lots of ripple peaks to lap down. The lapping should go fairly quickly if the gears are soft. With the Fellows system the cutter and gear are rotating during the cut, and the radius of the convex of the fellows is many times the radius of the ball end mill, so the ripple peaks are further apart for the same height, resulting in more peaks and valleys. I do think your approach is a good idea, and I would like your first try to be successful so if i seem picky it is because one must be fussy for gears to run quietly and smoothly. Do you have a way to hold the gears while lapping?
I did a couple of smaller gears on a Mazak integrex using an involute cutter that I had sliced in two and took about .035" out of the middle. For the finish cuts had 4 axis moving at once.
05-22-2011, 02:28 PM
Lapping fixture . . .
I could use the gearbox itself as a fixture for the lapping, but I think I will make a bearing fixture to carry one gear on and, with the fixture mounted on the cross-slide of my South Bend 16" lathe, drive the fixtured gear with the other one mounted to the spindle of the lathe. This way I can easily adjust the gear positions as the lapping proceeds. I am considering building a drag (brake) into the fixture so that the lapping will be more aggressive.
Originally Posted by hitandmiss
The same fixture, rotated ninety degrees should serve for lapping of parallel-axis gears, so it should have future uses.
05-31-2011, 10:43 AM
Progress report . . .
As of Saturday, the Lucas looks the same as the last pic posted, but the table & saddle gibs are installed & adjusted.
Back in my shop, I got the spindle sleeve installed & adjusted. The pic below shows the final adjustment of end play -- note the double slits in the nut so that the two cap screws lock the big nut up tight on the spindle sleeve. (Much nicer to work with than a pair of jam nuts.)
Due to the general nature of the spindle bearings, I thought I'd detail how I performed the adjustments. I will be referring to the diagram below of the origin (or close to it) of this type of mill spindle -- Brown & Sharpe.
First, a description: There are two bronze bearings that the spindle journals turn within -- the bearings are cross-hatched in the diagram. The "business" end of the spindle has a tapered journal (about 2.2 degrees per side on the Lucas) and the other end is a pure cylinder. Clearance within the tapered journal section is determined by axial position -- what may be confusing is that there are two things that work together to determine the axial position. At the right (as illustrated) end of the tapered bearing is a thick shim washer (in the B&S there are two: 4 & 5 in the diagram) that handles the main thrust of the tool being forced into the work -- its most common situation. When a drill bit is retracted the direction of the axial force reverses and the thrust is then carried by another planar thrust bearing which may be located on the other end of the tapered bearing (B&S) or at the other end of the spindle on the cylindrical bearing (Lucas). Cincinnati & others used similar systems.
The order I did my fitting was to work on the spacer thickness -- this can only be done when the spindle is disassembled and the spacer is ground to reduce its thickness, or replaced with a thicker spacer if that is necessary. In the case of the Lucas, the spacer needed to be reduced in thickness. In addition to grinding the spacer, I also used the ground spacer as a master and scraped in the bronze bearing's thrust surface. The side of the washer against the spindle sleeve's thrust face were in relatively good condition with only a slight amount of scoring, but the opposite side of the spacer and the bronze thrust surface had about a .003" departure from being flat. This took the form of a very flat cone with the bronze surface concave and the spacer convex. This was immediately apparent during the grinding and once the spacer was flat, using it to print ink on the bronze surface was easy. The least wear was the outer periphery of the bronze thrust surface, so I used it as a reference so I could scrape "straight down". I did the scraping with an 8" file with the end properly ground and honed. I scraped a even amount all the way, around and around, keeping the surface parallel to its original orientation.
I assembled the spindle sleeve and spacer into its bearings in the head casting with the axis vertical. This seated the thrust surfaces of the spacer and allowed me to move the spindle sleeve radially to measure the clearance in this position. I did a lot of research and the range of fits I found for a 4", low speed journal bearing was from .004" to .009". I stopped grinding the spacer when the total radial play was .005" with no clearance in the thrust surfaces. I then fit in a pair of .005" feeler gages (one on each side, so total was .005") to simulate oil spacing out the thrust surfaces. This gave a total radial play of .006" and showed that the radial play is relatively insensitive to axial play.
The hard part was over . . . if you are adjusting a mill spindle without the luxury of disassembly, then this point is where you start. The next step is to set the radial clearance of the cylindrical bearing. The bronze bearing for the cylindrical journal is cylindrical on it bore and has a tapered outside that has a matching taper in the inside of the casting that carries it. The bronze is slit in the same manner as a collet and a nut allows the bearing to be closed down. In some cases an opposing nut allows the bearing to be pulled in the opposite direction -- these two nuts (9 & 10 in the diagram) are tightened against each other when the adjustment is achieved. In the case of the Lucas, there are two nuts that are jammed against each other.
The final adjustment (nuts 6 & 7) is a second thrust bearing opposing that of the spacer that set how deep the tapered journal of the spindle seats into its bearing. The other bearing "works" when pulling a tool out of a hole and the balance of the oil films sets the actual neutral running position of the spindle. If the spacer is too thin, tightening this last thrust bearing adjustment will lock it, as will cutting with an aggressive thrust. I suppose that this is one way to determine if the spindle needs to be disassembled. I set this bearing for a total dry axial motion of .005". I did the whole job dry to make the movements easy and crisp. If there is oil in the bearings, it takes a "push" to squeeze the oil out, which takes a few seconds of maintained thrust. If you observe the motion of your test indicator, you can see the action of the oil leaving the bearing.
This morning I did a test fit of the actual spindle bar into the spindle sleeve, but the final assembly will come later at Tuckahoe. The next step is the final assembly of the head on the column. I already did a test assembly, so there should be no problems. I am hoping to re-unite the head/column assembly with the rest of the Lucas next Saturday.
06-01-2011, 02:33 PM
On schedule . . .
One side trip before installing the head on the column. The thrust on the head elevating screw is carried on a bronze surface on the screw which rotates directly on a spot faced area on the cast iron of the column. The oil hole did not communicate with this surface (I drilled it through), so there was a lot of galling. Facing the bronze in a lathe was easy, but I did not feel like trying to put some 500# of cast iron in a machine, so I scraped it in. I combined filing with scraping to speed things up, and alternated between using the thrust face of the bevel gear that fits in the bore of the casting and a small (4"x6") surface plate for spotting. The gear installs as oriented in the picture, but was inverted for spotting. The enlarged detail of the thrust surface was taken about half-way through the process -- I stopped once I had only a few of the deepest scores still showing and was getting a good bearing. Then I cut the top surface of the gear to compensate for the material removed -- this should put the gear near where it started.
Finally I have the spindle sleeve in the head and the head installed on the column.
Last edited by Archie Cheda; 06-01-2011 at 03:33 PM.
Reason: grammar . . .
06-02-2011, 01:18 AM
Thanks for your detailed explanation of the fitting of the plain bearings in the spindle.
06-02-2011, 05:29 AM
Adjustability . . .
Glad to be providing world-wide entertainment . . .
I will (eventually) be running the spindle in, while I have my IR thermometer in hand, and I'll report back what I learn. Part of the tuning is the weight of the spindle oil, plus the threaded adjustments can be manipulated, although the third (in order adjusted above) requires removing the whole quill assembly -- heavy, but only a six (large) bolts. The Lucas spindle speeds range from 15 to 150 rpm, so high-speed is not an issue.
For over 25 years my home lathe was a Myford Super 7 which has a hybrid spindle bearing design. The chuck end is a tapered journal bearing, with the hardened spindle journal running in a bronze bearing. The other end of the spindle has a pair of pre-loaded precision ball bearings and is set up so that in minutes, using a "spanner", the axial position can be adjusted. This allows the clearance of the tapered bearing to be tightened up a bit for lower-rpm precision work, or loosened up a bit to allow cool high speed operation. After a while, I found a happy medium and never changed it again.
P.S.: My memory tells me that John Oder shared an adjustment procedure with me, but my memory fails to find it after a lot of searching . . . thanks to John anyway.
06-04-2011, 04:07 PM
Column & bed re-united . . .
It is starting to look like a horizontal boring mill.
Barely visible in the rectangular opening on the back of the bed under the column is the 600# counterweight. The chain that connects it to the head is the same rusty one back in the early pictures. A few days in phosphoric acid and some light wire buffing worked wonders. Right now the weight is hanging on a bar that is inserted through the weight and two holes in the column on each side -- this is provided for shipping, but is quite convenient at the moment because the head is much lighter until I get the spindle, quill, and back gears all assembled. I am shooting for next Saturday . . .
06-05-2011, 04:19 AM
Nice work Archie, I was looking at the photos and diagrams earlier and wondering how you adjusted the main bearing once the spindle frame is fitted to the column. Having to remove the spindle frame to be able do it isn't the greatest idea the world's ever seen !
On the old " Richards " Horizontal Boring machines the main spindle bearing assembly was similar to yours but they had a long double tapered main bearing , one taper long and shallow and the other short and at about 45 degrees to prevent seizing up if the bearing was abused or overadjusted. The main spindle sleeve which also carried the built in facing slide fitted into this with the travelling spindle running through the main spindle sleeve . On the back end of the main spindle sleeve instead of plain locking rings they had a neat worm and wheel arrangement.
If you needed to tighten the sleeve into the facing slide bearing to adjust the running clearance you removed a little panel on the side of the spindle frame then carefully rotated the facing slide until two factory fitted markers lined up , one on the spindle frame casting, one on the facing slide itself. When the marks lined up the adjusting worm socket would be dead in line with the little window, you could then reach the adjusting worm by means of a long square ended tee wrench, turning that rotated the worm wheel ( the lock-nut on your design ) and adjusted the main bearing running clearance. Easy, took all of about 5 minutes if you took your time.
Anyway it looks like you're nearly there now, it'll be interesting to see how the alignment checks pan out. Regards Tyrone.
06-05-2011, 05:44 AM
99 years and counting . . .
I am "almost there" with regards to my short-term goal of giving visitors to this year's Tuckahoe show something to see that looks like a horizontal boring mill. There are a number of gears to make and I intend to "flip" most of the rest of them. The flipping sounds easy, but Lucas made the gears in pairs, so I have to cut them apart and make spacers, which is all going to take some time. My planned date for having the Lucas operational is in time for next year's show, in time for its 100th birthday.
Originally Posted by Tyrone Shoelaces
If I can get the quill, back-gear, and spindle assembly on the head next Saturday, I hope to do some alignment checks the following Saturday. The only two planes I removed serious amounts of material from were the horizontal surfaces where the saddle bears on the bed and the table bears on the saddle. In both cases I think I succeeded in scraping "straight down". I had enough confidence that I mounted the counterweight in the column, but a sharp eye will show that I have not tightened the bolts holding the column to the bed. Under each bolt is a pad that I will have to scrape in to do any necessary final corrections to the Lucas alignment. In about two weeks I should be able to report how much correction is needed.
The Richards' easy adjustment sounds practical -- from the damage that shows on all the pin holes on the Lucas' adjusting rings, there was a lot of adjusting performed over the years. Like the Myford spindle I mentioned, I think that the British machine tool builders realized that while adjusment for wear would eventually be performed, that if the adjustment was convenient enough, adjustments would also be made to handle varying conditions.
Thanks to you and everyone else following my slow progress,
P.S.: I will be at my Niece's wedding in MT in July and will not be at the show, but the Lucas will be there to see for those who attend. The following year I hope to be there making chips on the Lucas!
Last edited by Archie Cheda; 06-05-2011 at 06:47 AM.
Reason: spellin . . .
06-07-2011, 01:40 PM
06-11-2011, 10:24 AM
Ready for this year's show . . .
Now it really looks like a machine tool:
I reviewed my list of tasks and find I am about three-fourths of the way through the list, which matches my own estimated progress. I still have a lot of gears to deal with and some other parts to repair or fabricate, but having the Lucas running within a year seems quite possible.
Thanks to everyone for the encouragement,
P.S.: I mounted up the vertical drive-shaft to do some measuring. There is a notch flame-cut in the square tubing the Lucas is sitting on -- visible in the lower left of the picture. The original shaft actually is long enough that it needs a hole in the floor if one wants to lower the head to the bottom of its slide on the column. The notch gains about three inches, but that was not enough because a previous owner also flame-cut the end of the shaft off. As pictured, the head may be lowered fully. I took measurements so I can measure up the position of the miter gear in the gearbox that drives the shaft. We will then decide to use the shaft as is or fabricate one of the original length.
06-11-2011, 11:47 AM
That look awesome Archie!
06-11-2011, 12:40 PM
Archie: When you come to Montana for the wedding you better bring a boat so you can get around. I've enjoyed the lucas project, I'ts a work of art, I'm sure it never looked that good new from the factory. Welcome to the Big Sky State, may your niece have a warm dry wedding. Ron