Retrofitting the SD400 lathe for proper oiling.

[RaisedByWolves]

I have had two of these machines for a while now and love the capabilities these have for such a compact machine.

The one thing I don't like is lubricating them. There is no provision to oil the ways on these or some other areas like the Tailstock or the apron gear shafts, so you're left with some impractical options.

I'm going to fix that on my machines and show you a simple (?) way to go about retrofitting your own machine if you would like to follow along. The methods I employ are certainly not the only methods to get this done, but for me with my skillset its simple enough.


I'm going to start with the saddle way lubrication as its my current project and work my way up.


I looked all over for small Gits type oil cups and found these on E bay. They have a 6mm-1 thread and are kinda tall at 3/4", so the first order of business is to shorten them. This is not expressly necessary, but as you'll see it will allow more positive oiling when the next few steps are taken to get the oil where it needs to go.

Here's the oiler as shipped.

And the location I intend to put it.

To start off with I put the oiler body in the 4 jaw chuck and indicated them. Getting them within a couple thousands is fine as you're basically just shortening them and recutting the cap retainer band groove.

With that done I turned .225 off the end of the oiler:

Then I turned down one peak of the hex shaped body for clearance for the new retaining band groove.

Then I simply recut the retaining band groove.

Perfect!

I then assembled it all back together. Better than the day it was made and .225 shorter than it was.

With that done I set the saddle in the B-port and after taking careful measurements found a location near the center of the rear way that would not intersect with a nearby gib attachment screw hole, and drilled it for a 6mm-1 thread for the oil cup.


The Allen key denotes the depth of the existing screw hole I’m trying to avoid and the location of that hole….tight!

I had less than 5/16” of depth in this hole so again I shortened a tap and tapped the hole.

With the hole tapped I test fit the oil cup, and while really close to the top of the ways, it fit without any interference.

Then I had to cross drill an oil gallery to the center of the rear saddle way. I set the saddle up on a random angle that would let me get deep enough to reach the center of the back way and drilled it to the proper depth. The angle does not matter for this step so I just fudged it.

Checking depth and setting the quill stop.

Once I had that set up I had to spot face the bottom of the hole as it was angled from the drill bit tip. I went in with an 1/8” 3 flute endmill to make the spot face.

I was able to use the camera on my phone to inspect the operation as I worked, which was great as I didn’t have to move the machine it break setup to check progress.

I repeated the process with a center drill.

I then drilled it to the depth I had set with a .116 #32 drill. After this I set up and located the position for the 2nd half of the oil gallery, and drilled through from the face of the way down to the first hole using the same sized drill..

I drilled the oil gallery hole nearly perfectly at the end of the cross hole, very happy with that. If you look closely you can just make out the crescent where the cross hole and the 2nd hole intersect.

Then I set the saddle up on the mill and using an 1/8” ball mill made the oil groove.

With that done my attention turned to the oiling of the front V way on the saddle. This way gets oil through a slit in the saddle centered on the inverted V way, and while this works OK, I figured while I was here I would give the oil a lil help. You can see in this pic how far back the slit is and how tight the walls of the clearance channel in the saddle are to the cross slide lead screw. This groove will allow gravity to carry the oil to the slit and onto the way quicker.

The cross slide screw comes in from the left here and you can see the slit marked by the red arrow. The slit is partially hidden from above and there is no direct way to get oil in there.

I angled the saddle slightly in the mill and using the same ball mill made a sloped oil groove leading to the oil slit.

Next Ill add oil grooves to the V ways.

 

[RaisedByWolves]

Ok, back to this.

To make the oil grooves I carefully laid out lines where I wanted the grooves. Notice they are splayed out wider on one side. This is due to the oil groove I cut in the opposite side in the last post is off to the one side, and will likely put oil on that side first, so the corresponding grooves are farther apart on that side. This will in theory give the oil time to settle on top of the way and more evenly disperse between the two sets of grooves.



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All laid out. The afore mentioned groove on the opposite side comes in from the bottom of this pic.

I used a DotCo pencil grinder and a 3/32 rotary file to make the grooves.

And a couple minutes later the grooves were done.

I then switched to a fine pointed burr to get into the part of the oil grooves that were too close together to get the ball burr in.

With that done I turned to installing ball oilers in the saddle, and small 1/8" copper tubes to carry oil to the longitudinal drive gear shafts.

I mounted the saddle on the apron and set it up in the mill. Here I'm finding the proper depth to drill the oil holes with a A drill which is the proper size for the 6mm ball oilers I purchased. I want the holes to go through the saddle and just touch the apron, but enough to form a slight funnel for the oil. I also want these ball oiler holes to be large enough to hold a bit of cotton to catch any debris that might get past the ball, so I drilled them through to the full size of the oilers minus a few thousands for a nice press fit.

Cleaned the chips off and pressed in the oiler buttons.

Having had the drill spot the apron, I picked up these locations and through drilled them down to the gear shaft bores with a #32 drill. You can see here the small funnel shaped spots and the copper tubes being brought to length.

And here they are brought to length but not yet seated.

Once they were fully seated I added just a small dot of the green elixir to cement them permanently in place. I used less than half a drop per end and let it wick around.

And heres a shot of the apron all back together with the oiling tubes i.

Ill probably add more oiling points as I progress finishing this machine. I would like to add oiler buttons to the compound and cross slide as well as some other areas also, so well see.

 

[Ulma Doctor]

Nice work, i’ll be very interested in how it works out.