Cross Slide and Compound Reassembly

Today I was able to reassemble the cross slide and the compund. I also managed to test fit the apron to make sure that the replacement pinion shaft is working.

The first step in rebuilding the cross slide was to add some sort of anti-backlash nut. First, I bored out a 5/8 hex nut as a housing.

Boring out nut

 This housing fits over a bronze sleeve that has been tapped with 1/2-10 left handed Acme threads.

Modified cross feed nut, sleeve, spring washers, boronze sleeve, Nut housing and anti rotation bar

 I tapped the oil drain hole in the bottom of the existing cross feed nut for a M5 screw. Next, I drilled two holes 30mm appart through a piece of the old cross feed Gib. This will keep the modified hex nut from rotating relative to the main nut.

Sleeve, main nut, springs and housing on screw inside of the saddle

 Once on the leadscrew, the bushing is screwed up against the main nut with the spring washers providing the preload. The bar keeps the housing aligned with the nut while a set screw holds the bushing inside the housing. This way the bushing can move axially to help compensate for uneven wear of the screw threads.

Initial Installation - note the extra material on the bar

After the initial installation, I noticed that the extra material on the bar was reducing the available stroke. So I milled off the ends and re-assembled everything.

Forward travel

Milled off bar at front

Rearward Travel

Milled off bar at rear

After getting the screw back in, I added the compound, the front and rear lower guides and test fitted the apron:

Saddle and Apron back on the lathe :)

Current state of Saddle and Head Stock

I am slowly getting ready for fist cutting :) The main jobs left are wiring up the drive system, preparing a spot to mount the lathe,fitting the BXA tool post and finally getting that worm gear to power the apron. In addition, I need to fabricate a replacement for the broken handle on the Gear box and re-install the lead screw and the thread dial.

Gear Train Re-assembly.

Today I was able to put the rest of the gear train and the QC Gear box back on the lathe. This Mostly completes the headstock re-assembly.

Before

After

Gear train before

Gear train now

I was also able to test fit the new gibs for the compound and the cross slide :

Test fitting the new gibs

Replacement Gibs

The gibs for both the compound and the cross slide were in need of replacement. The compound gib was the original, but it looked like it had been bent and re-straightened. The cross slide "gib" looked like a piece of steel from the home depot hobby rack with some crude dimples drilled in the back.
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Back side of gibs - Top to bottom: Old Compound,New Compound, Old Cross slide, New Cross slide

Front  side of gibs - Top to bottom: Old Compound,New Compound, Old Cross slide, New Cross slide

The replacements are made from ground low carbon steel flat stock from McMaster. The Compound is 3/32 thick while the cross is 1/8 thick. To properly bevel the edges and to get the maximum bearing surface possible, I clamped the raw stock in the compound and cross slide housings and held the housings in the mill.

Beveling the compound gib

Beveling the cross slide gib

To cut the set screw pockets in the back, I set up my Tom Lipton style mini palete at a 30 degree angle.

 I put two screws in front to line the gib up in Y and used some mini toe clamps to hold the gib in place. I used a set screw in the housing to mark the location for each dimple. Using a small end mill, I cut the pockets sideways. This way the dog point set screws have a nice flat surface to push up against.

Lathe Motor Mount

In order to mount the new brushless motor, I needed to make a motor mount. I started off with a piece of 8x8x1/2 Aluminum angle. Unfortunately, I didn't measure the slots in the base before I ordrered the material, so I only got a 6" wide piece.... and the slots in the base are on 6" centers...:(. So I picked up a couple of stainless steel cutoffs at my local surplus metal dealer and made some spacers.

To bore the pilot hole, I set the angle up on some 1-2-3 blocks and held it down with a couple of strap clamps. I used a large drill (61/64) to drill out a starter hole. Then I used a boring head to slowly open the hole up to the 110mm pilot diameter for the motor.

Drilling the starting hold for the pilot bore

First pass with the boring head

Manny passes later

Almost there :)

After boring the hole, I drilled and tapped the four M8 holes. The other leg of the angle got four notches to clear the 3/8 bolts and a pattern of clearance holes for M8 screws to attach the spacers.

After cutting the spacers to length, I surfaced them top and bottom to make sure they were the same size. Then I drilled 1/2" holes for the mounting bolts and tapped two M8 holes for attaching the angle.

Stainless Spacer bars

I used 3/8" carriage bolts to attach the spacers, since they fit the slots in the base well and can be tightened from the top. The angle and the Motor are attached with M8 screws. I like metric fasteners whenever possible, but when interfacing to older machines this may not always be practical.

Motor on Mount attached to base plate

Closeup of spacers on base.

I was finally able to get the whole assembly wrestled into the cabinet. Unfortunately some of the sharp corners left gouges in the paint. I will go back for some touchup work once I get everything installed.

Installed in the Lathe

Apron Rebuild

Ok, today I got my apron mostly reassembled. There were a couple of parts that needed to be replaced. Thanks to the shop at work I was able to turn these while without a lathe...

First up is the Idler bushing on the Cross feed clutch gear. This is just a simple stepped bronze bushing, but the walls are fairly thick, so I couldn't find an off the shelf one to modify. I used a 2" drop as a starting point and just whittled away.

New bushing (pressed into gear) and old one for reference

The next item to be replaced was the pinion shaft that rides on the rack. The gear teeth were worn out and the shaft had about .002"-.003" of wear at the bearing surfaces. I bought a new 20 tooth gear and made a sleeve to fit over the back to get the length and diameter to be the same as the old one. I then made a replacement shaft out of pre-hardened 4140. I think this will be my go-to shaft material for future projects. I used a carbide insert and as long as I didn't try to take too shallow a cut, I could get a really nice surface finish. I turned the main shaft down to 0.687" and the stub to 0.501 to give a decent prss fit into the gear. One slight modification over the original design was the key. The Clausing shaft has a #3 woodruff key, but I couldn't find the right size cutter at work. So I made a flat key instead.

Old Pinion (top) and new parts

New Pinion assembly (Top) and Original for comparison.

After the parts were done, it was time to put the whole thing back together.

Front of the rejuvinated apron

Half Nuts - Before

Rear View - After

Top View - Before

Top View - After

I decided to leave the handles unpainted for now. I think the clutch handle looks much better now, but I am not sure about the half nut handle yet. I am still waiting for some good weather in Pennsylvania so that my source can finally get the worm gear out of storage. Also, at some point I am going to have to figure out how to rework/replace the half nuts, since the threads are pretty worn out.

Lathe Painting - Part 3

I was able to make some more progress on the painting these last two weekends.

Rear cover, apron and a couple of handwheels

 I painted the rear cover and the apron outside and worked on the bed and the headstock in the garage.

Bed and Headstock

I checked on removing the headstock from the bed, but the Clausing service manual didn't reccomend it. So I painted the two parts together.

Together again at last :)

After a week of drying, I was able to put the bed back on the base today :) I also got the spindle re-installed with new oil seals.

Old Motor Mount

New and imporved Motor cabinet

 Here is the new motor mount in the now clean base. I will need to do some touch up work on the bottom. the Motor assembly is not easy to wrestle in and I got some gouges in the paint :(