Spiral Milling along with a bit of turning (large, lots of photos)
Doing some lower end work on an old car engine. Shop is working on a 1913/14 Turcat-Mery and the job includes a complete rebuild of the engine.
My involvement centers on the lower end...new main bearings (bronze shells with babbit) and rework of the cam bearings....
The rear oil seal for the crank consists of a pair of brass shells machined with helical grooves that run in a close fitting bore in the crankcase and sump. The originals were in rough shape and after the line boring of the mains and truing
of the slinger bore a new better fitting slinger was required.
The part is made in two halfs to allow fitting to the crank forward of the rear flywheel flange. (i have never seen it done this way before, but the part and crank are original)
There are some features on the IDS of the slinger halfs....there is a notch bored into the ID that registers on a like shoulder on the crank.
Started out by blanking the material out on the lathe...well oversize on the OD and under on the ID..... Once blanked out the stock is removed from the lathe and cut into two halfs on the mill using a slitting saw.
The halfs are then surfaced...via fly cutter to make the parting line surfaces flat and both halfs the same height. The two shells are then lapped on a flat surface using 320 w/d paper.
The parting surfaces are then tinned and soldered together using soft solder ..(the stuff with tin and lead..not that water pipe sweating crap)
Once joined the parts are returned to the lathe and the ID and OD finished out. For this job i left an extended section at one end of the part to allow gripping when it came time to do the grooves.
For turning i find using the 6 jaw works well to hold the soldered shells...they are not round and by gripping with the parting lines orientated between a pair of jaws you get good enough grip to turn the ID.
Once the ID is done, fitting up on a spud in the bore at the chuck end and squeezing against the opposite face with a disc having a center hole using the tail stock live center, one can turn the OD without
too much trouble. Care must be used here to not clamp or work the part too hard for danger of the solder failing and the halfs coming apart and out of the machine.
Using a 4 jaw or a three jaw with soft jaws bored to the part size also works....
For the grooves, i went old school and enlisted the use of my first gen FP2, fitted up with the spiral milling attachment and the precision boring head.
Here the part is mounted using a 4 jaw chuck and supported via the tail stock on the attachment.
The had is set to index 32 teeth and using the original as a model i setup the gearbox to produce a lead of 8" (original setup was a bit different at 8.8' lead, but that was as close as i could get without making some gears, and i deemed it "not critical")
Part was touched off and moved to get the spindle on center. I choose to run the the precision boring head as it increases the output RPM...I needed to run a small end mill (5/64") and I wished to get the spindle running as fast as possible.
The step up on the precision boring head is 1:3.15 so an input of 2000RPM will give 6300 out. A selected spindle speed of 1600 gave just over 5000 RPM at the tool. (the max continuous speed called in the manual is 5000 for that head)
More to follow
Another view of the dividing head setup....Also note the spiral attachment is set to cut a right hand helix...Would not do to get that wrong!
The cutting begins. Some notes. I needed to hold a 3/16" tool body and i did not have a standard 40 collet to do that. I uses a straight shank (3/4") ER16 holder gripped in a Deckel collet.
This allowed some extension to get clearance for the spindle and the chuck jaws on the dividing head.
Also i ran this job in one direction only...feeding from right to left as you face the work. Another advantage of the precision boring head. At the end of cut i could withdraw the spindle for work clearance and move back to begin a fresh cut
after indexing. I used the factory depth setting or limiting feature on the boring head to give a positive depth return.
Also it is necessary to start your cut away from the part to allow the slack of the gear train to be accounted for.....
At completion of two passes for depth the part is removed. I made this from 660 bronze and cut the slots dry, using a vacuum to collect the swarf.
Note the extension on the part , and if you look carefully at about 5:00 you can see the seam where the two half were soldered together.
Final operation was to re-chuck the part and remove the extra portion that was used to grip the slinger while on the spiral milling attachment.
Use of the soft jaws here gives good support on a small grip length...note use here of support.
Part was cut almost free then i used a hacksaw to finish...Did not wish any extra force to be used here.
Finishing the back of the slinger ring after extension is off....
Slinger ready for the next step...
A bit of heat and the two halfs are free of each other (for awhile only) Two half circles mated and matched!
Now it just needs to be fitted to the crank, and finished on the OD for the correct fit to the case........
Final work on the slinger:
Halfs are fitted to the crank and soft soldered in place. (crank is steel...!)
Crank with slinger is then chucked in a lathe and dialed up to run true (the crank) .
The OD of the slinger is then finished turned to give the proper running fit to the case bore....the slinger ring (disc) is also trued up.
Crank mocked up in case to check fit and front to back clearances of teh slinger.
The big picture.
Yep really crappy work as usual Ross... Nice job and thanks for sharing, one question for you about the soft solder. If you solder the two halves together wouldnt the thickness of the solder effect the fit after it is removed?
Yes the solder does have thickness..pretty much just the wetted surface from being tinned and wiped ..when i take the halfs apart,then re-solder on the crank it all goes back pretty much as it was.
Of course i never trust this totally, and always design to finish after fitting.
I use the above process to make bronze bearing shells for mains and cams, works well usually allow a bit extra in the OD for crush with the main caps...and some careful lapping of the parting faces after babbitt
gives the crush needed t live in an engine.....
what is heat source for solder joints?
Wow... Cool stuff Ross.
I love old engines... Such crazy engineering techniques are employed.
Very, very inspiring as usual. Thanks for sharing. Is that a sub-plate on the FPNC in the 2nd pic of the 1st post? I don't recall it being discussed before.
Very nice work, and interesting too. Pains me to see that beautiful Harrison CNC lathe in the background though Years later I have yet to even come close to finding another one like that....that is one rare little machine ! If only Makino had made one that size and type with the same control that's on the KE mills...that would be the Holy Grail !
How long did it take to set up the spiral milling attachment, from the time you started to take off the table to when you were ready to chuck up your part?
heat source for doing the soldering was oxy acetylene torch....to break the halfs apart a MAPP gas torch was enough.
As to soldering to the crank, again the oxy acetylene rig was used....Crank is steel forging as far as i could tell. No surface treatment. Pretty soft, but all bearings tin based babbitt.
Yes that is a sub plate. Sits on the table of an FP2NC that i bought from "SwarfRat" just before Christmas. That machine is one of the Don Sentner Heidenhain retro fit machines.
I would have a hard time making an accurate time line on the total....The FP2 you see is at home. It was already setup with the spiral milling attachment....still setup from the last spiral job.
used it and never needed to remove it from the machine....my guess would be about 30-45 minutes if you had the lifting ability at hand.
As to the setup on the attachment, think i spent about 45 minutes setting the gear train and finding the dividing plate (had to remove it from my dividing head, which required digging out the head from the cabinet)
Oh and i think about 15 minutes to get out the precision boring head, remove the slotter and fit the boring head...another 10 or so to tram the head....
Most of the prep work was done in small pieces after work, a bit at a time. I knew i was going to need to run this job so i did the prep piecemeal to keep the job from needing too much time all at once.
Wow! Someone drank their Craftman Juice this week . Very nice work Ross! Thank you for sharing this with us, as I had no idea of the craftsmanship that goes into this type of repair/restoration. It appears your talent is an exceptional match for the absolutely beautiful shop you are working in!
1919 Turcat-Mery~~~~~~~~~~~ the ICE-man commeth
thanks for info on soldering
apologies for what will look like thread diversion-
this is a local story of same motor car make
Seattle antiquity dealer buys 1919 Turcat-Mery in Netherlands and brings to USA in 2005. Spends one million usd on purchase and import. French government says car was removed illegally from France. Home Land Security branch ICE investigates and finds owner-importer falsified documents at time of import.
Owner-importer agrees to return auto to France at his expense. Video shows car load into 747 freighter.
1919 Turcat-Mery in Seattle (02/17/09) on Vimeo
Historic antique vehicle returned to France
dang it man, that's some beautiful machinery you have there, I almost got a boner
That's some high end lower end work!
And the car.....................
Lots of bright work on this car....would keep "your man" busy polishing all that brass.....
thanks for pics and hx Ross
are the pistons and conn rods original?
is the drilled flywheel original?
Seattle seems to have a sizable colony of worshipers of vintage french motor cars.
Richard Adatto I believe has authored several books on these and is judge? at Pebble Beach
Someone else said it, too -- inspiring! I wish I had a spiral attachment for my FP1 so I could make spirals just for fun.