- Joined
- Apr 23, 2018
- Messages
- 6,617
Hey, Rick, I see you got your big South Bend running! Any issues after you swooned her? I got the "bodywork" straight on my Nardini, it wasn't so bad in the end.
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POTD- PROJECT OF THE DAY: What Did You Make In Your Shop Today?
- Thread starter wachuko
- Start date
Most of the repairs are documented here.
Need advice for repairing damaged SB 14-1/2” lathe
I posted in another thread about the tumble my new SB 14-1/2 took when it turned over removing it from the skid. I know I’m new with little credibility on the forum, and what I’m needing may need old-friend status with some of you. I get that, and wish I had time to earn more respect here, but...
www.hobby-machinist.com
I replaced the destroyed taper attachment, rebuilt the cross slide with a new screw, and that converted it to the newer design with ball-bearing thrust washers in the taper attachment. I then pulled the spindle and replaced the oilers in the headstock, and readjusted the bearings with new shims.
Then, I rebuilt the apron, and repaired the broken idler cam using epoxy reinforced by a bolt through the power-feed lever shaft. All new felts there, too.
Then came the CXA tool post installation.
I have not yet rebuilt the quick-change gearbox or the end gears—still on the to-do list.
But just this evening I rebuilt the compound with a new nut, and installed a .016 shim behind the handle and tightened the replacement gib. No more play and 0.006 of backlash. A prior owner had used a set screw instead of a brass dog screw to lock the scale, and buggered up the compound screw. Took some effort to fix that damage. I replaced it with a brass thumbscrew I had on-hand.
Rick “had to work around a loose compound turning the taper on the drill press spindle—no more” Denney
- Joined
- Jul 14, 2017
- Messages
- 2,451
Today i spent some time in the big garage working on cars. Couple small jobs on the little niva but most of the time i spent on the W210, Bumpers got back from paint the paint shop managed to brake on off the tabs between the lights. With the bumper and sideskirts mounted i checked all the systems and the A/C was the only one not working. I vacuum the system then i fill it with R134a, it seams to be working it's cold but demist the windscreen well.
- Joined
- Sep 8, 2019
- Messages
- 4,392
I wasn’t able to be very productive because of a sore neck, but I gave the whole garage a thorough cleaning. Following this, I ***organized the position of things*** because it is getting unmanageably crowded in there.
I have a lot more fun in the shop if it is clean and organized.
All that I want to do in the shop nowadays is practice welding, and it was able to get in one gas-welded bead.
Some old-timer has offered to give me a nice long gas welding lesson next Sunday. This is the same guy that gave me the torch cutting lesson, and he sure set me straight on that.
I have a lot more fun in the shop if it is clean and organized.
All that I want to do in the shop nowadays is practice welding, and it was able to get in one gas-welded bead.
Some old-timer has offered to give me a nice long gas welding lesson next Sunday. This is the same guy that gave me the torch cutting lesson, and he sure set me straight on that.
Last edited:
- Joined
- Oct 7, 2020
- Messages
- 2,128
I ment to post this the first time but I used one of @Doug Gray tools to complete the task. It worked great, Thanks Doug.
- Joined
- Apr 23, 2018
- Messages
- 6,617
Today, I got closer to powering my big man lathe. That draws big man horsepower, which requires big man components and big man wire.
While it all makes me feel big and manly, I cry big man tears because it can only come from my big man wallet.
While it all makes me feel big and manly, I cry big man tears because it can only come from my big man wallet.
Problem: I don’t own a mill. Several months ago I scored a milling attachment for a South Bend 16” lathe, figuring I could do what it takes to make it fit my 14-1/2. It mounts in lieu of the compound, and the SB16 has a couple of threaded holes to a cross-slide adapter or to the cross slide itself. This one was modified to fit some other lathe and has a big hole in the middle of rotation that isn’t original. I thought I’d make an adapter to fit that hole and provide the round dovetail used by the 14-1/2 compound.
But I don’t want to mount it at that location. I want it closer to the back so that the cross slide range gives me access to everything in the milling attachment vise jaws. So I decided to machine a dovetail mount like the one on the compound, and the put it wherever it needed to be on the bottom of the milling attachment. I’ll do that with probably two grade 8 3/8-16 screws plus a couple of alignment pins.
This post is about machining the dovetail.
I’m a noob, so I made some rookie mistakes. The resulting workpiece that I picture is the second one. (The first one turned out fine except the dovetail is backwards—2.5 (nominal) minus 2 is one half, which means a quarter inch on each side. Not a half inch. Dumbass mistake.)
I measured up the dovetail on the bottom of the compound. Here’s the sketch. It’s upside down—the dovetail slopes in towards the top, so that the lock screws pull it down against the cross slide.
I had a 3” bar of 12L14, and I first faced it off. I’m using the fat side of a CNMG insert for facing.
And then I turned it down to 2.497”.
I’m using a CNMG insert for turning, running about 250 RPMs. The feed rate was .005 per revolution, and the depth of cut was .020. (The lathe wasn’t happy with .030, which tells me something’s not right. I still need to rewire the single-phase motor for 240VAC. The power level seems low. It’s not the bearings in the lathe power train, which run free and are in spec.)
After getting the correct diameter, I used a cut-off tool to undercut the narrow part of the dovetail. I made sure the dovetail was oriented so that the face I just cut to be against the bottom of the milling attachment. I wanted all reference surfaces machined in one setup.
I used a VNMG tool to cut the dovetail, with the compound at the 24.8 degrees of the part I was copying, sweeping across the corner and manually feeding the compound. I took .020 cuts by feeding in the cross slide. That worked pretty well. I also used it to clean up the flat surface.
Then I measured over an extra .050 and used a cutoff tool to part it off. I had to slow it down, running at 60 RPMs in the back gear. I manually feed the tool. Halfway through the insert broke and the shards buggered up the cut. Lots of chatter. I locked the carriage between two micrometer stops, and lined up the compound to be straight on so that if it walked it wouldn’t be a problem. Results were ugly but i was going to face off the part anyway.
I turned it around in the chuck and indicated it in as best I could. And it was good enough—that face of the dovetail is not a reference surface but I still bumped it to well within a thousandth of being parallel to the other face.
I then finished the facing down to the .949 target thickness. The dimension wasn’t critical but I was trying to hit it anyway.
My regular mic wouldn’t fit behind the part and stay square. But I had recently bought a cheapie import tubing wall thickness mic from Shars, and that was what I needed I fit in the space between the part and the chuck body.
After chamfering and deburring, I measured the part with my good older Fowler mics that I bought maybe 20 years ago when they were made in Japan. The diameter is a thou and an half over, which will mean a closer fit, the thickness is within a couple of tenths, and the dovetail dimension is within 3 thousandths.
At this stage of my learning, hitting dimensions reasonably well is a good outcome.
Next step is to install it on the bottom of the milling attachment at an appropriate spot. My worry is that this is too small a mount for that 75-pound milling attachment, but time will tell. I plan to use two or three 3/8-16 grade 8 screws (tight!) and a couple of dowel pins.
Rick “4-day weekend over” Denney
But I don’t want to mount it at that location. I want it closer to the back so that the cross slide range gives me access to everything in the milling attachment vise jaws. So I decided to machine a dovetail mount like the one on the compound, and the put it wherever it needed to be on the bottom of the milling attachment. I’ll do that with probably two grade 8 3/8-16 screws plus a couple of alignment pins.
This post is about machining the dovetail.
I’m a noob, so I made some rookie mistakes. The resulting workpiece that I picture is the second one. (The first one turned out fine except the dovetail is backwards—2.5 (nominal) minus 2 is one half, which means a quarter inch on each side. Not a half inch. Dumbass mistake.)
I measured up the dovetail on the bottom of the compound. Here’s the sketch. It’s upside down—the dovetail slopes in towards the top, so that the lock screws pull it down against the cross slide.
I had a 3” bar of 12L14, and I first faced it off. I’m using the fat side of a CNMG insert for facing.
And then I turned it down to 2.497”.
I’m using a CNMG insert for turning, running about 250 RPMs. The feed rate was .005 per revolution, and the depth of cut was .020. (The lathe wasn’t happy with .030, which tells me something’s not right. I still need to rewire the single-phase motor for 240VAC. The power level seems low. It’s not the bearings in the lathe power train, which run free and are in spec.)
After getting the correct diameter, I used a cut-off tool to undercut the narrow part of the dovetail. I made sure the dovetail was oriented so that the face I just cut to be against the bottom of the milling attachment. I wanted all reference surfaces machined in one setup.
I used a VNMG tool to cut the dovetail, with the compound at the 24.8 degrees of the part I was copying, sweeping across the corner and manually feeding the compound. I took .020 cuts by feeding in the cross slide. That worked pretty well. I also used it to clean up the flat surface.
Then I measured over an extra .050 and used a cutoff tool to part it off. I had to slow it down, running at 60 RPMs in the back gear. I manually feed the tool. Halfway through the insert broke and the shards buggered up the cut. Lots of chatter. I locked the carriage between two micrometer stops, and lined up the compound to be straight on so that if it walked it wouldn’t be a problem. Results were ugly but i was going to face off the part anyway.
I turned it around in the chuck and indicated it in as best I could. And it was good enough—that face of the dovetail is not a reference surface but I still bumped it to well within a thousandth of being parallel to the other face.
I then finished the facing down to the .949 target thickness. The dimension wasn’t critical but I was trying to hit it anyway.
My regular mic wouldn’t fit behind the part and stay square. But I had recently bought a cheapie import tubing wall thickness mic from Shars, and that was what I needed I fit in the space between the part and the chuck body.
After chamfering and deburring, I measured the part with my good older Fowler mics that I bought maybe 20 years ago when they were made in Japan. The diameter is a thou and an half over, which will mean a closer fit, the thickness is within a couple of tenths, and the dovetail dimension is within 3 thousandths.
At this stage of my learning, hitting dimensions reasonably well is a good outcome.
Next step is to install it on the bottom of the milling attachment at an appropriate spot. My worry is that this is too small a mount for that 75-pound milling attachment, but time will tell. I plan to use two or three 3/8-16 grade 8 screws (tight!) and a couple of dowel pins.
Rick “4-day weekend over” Denney
- Joined
- Jul 14, 2017
- Messages
- 2,451
Today i spent the free time buying steel, rearranging car parts. I bought some angle iron, flat steel, square solid bar for the snow plow project and some thin square tubing for more shelves. Then i got the VW golf seats out, and the floor pans. One of the issues i've been having with my little niva is very hard to get in the back seats. I used the seats from a 4 door with a hinge, they are very comfortable but too big and tall for the little cabin in the niva. The golf seat is from a 2 door, but the mounting points and rails are welded to the floor pans. The plan is to leave the drivers seat alone just change the passenger then clean it and put on the seat cover from the old one. Cutting out and welding on the seat rails is way to hard so i may just have to place it and weld it in place, i'll have to place it to see how thing line up in the interior.
