The Ramblings of hvontres: 2014

Sunday, May 4, 2014

Some more Lathe Improvements

This weekend I was able to squeeze in a couple of lathe improvements

First I was able to get my 4 Jaw chuck up and mounted. Earlier in the year, I managed to pick up two items relatively cheap on e-bay.

The first was an old B-42 Collet Closer with an L-00 backplate. Due to the high cost and limited range of B-42 collets the closer will be of limited use for now. But I have plans to convert it to use ER-40 Collets that should be much cheaper and easier to get. But the price I paid for the whole setup was less than a new backplate, so I got the closer for free :)

Front of Collet Closer

Rear of collet closer

A little later, I found a nice 8" Horton 4-Jaw chuck. Appearently, nobody else did, and I got a nice solid 4-jaw for about $75 shipped. I think my mail person now hates me, since this little beauty came packed in a medium flat rate box. I guess if it fits, it does ship :)

Back of 4 Jaw

Front of 4 Jaw

In order to mount the chuck to the backplate, a few modificatons were needed. First off, the original mounting screws were 7/16" Filister head screws that went through the old backplate and had heavy hex nuts on them. I decided to replace them with 3/8"-18 Sochet head cap screws. This meant that the counterbores in the chuck needed to be a little deeper to deal with the heads.

Chuck with Jaws removed clamped to the mill

I removed the Jaws and clamped the chuck to the table on the mill. In order to protect the screws from cast iron filings, I filled the slots with shop rags.

Inidicating in the old hole - Counter bore tool also shown

Next I indicated in each of the counterbores and ran a 3/8" counterbore tool to ~3/8" depth.

Earlier, I mounted the backplate and re-faced the flange to minimize the runout on my lathe. I also turned down the outside diameter to fit the recess in the 4 jaw. The bolt pattern for the collet closer is still intact, so this backplate can be used for either application . The backplate was clamped on the mill and I indicated off of the boss to find the center. I then Drilled and tapped 4 3/8-18 holes to match the chuck.

Backing plate on mill with holes drilled and tapped

Here is the backing plate mounted to the chuck:

Backing plate mounted to chuck

And here is the chuck mounted to the lathe:


Chuck mounted on the lathe

The only thing left at this point is to make a replacement chuck key for the 4-Jaw. The 3 Jaw is a 1/2 square, while the 4-jaw is a 7/16.

The second job this weekend was to improve the legs on the lathe. When I first setup the lathe, I just mounted adjustable feet from McMaster to some 1/2 screws. Unfortunately the mounting tabs on the lathe are not very thick, so the feet always looked a bit precarious.

Old Foot Setup

I picked up some thick walled 2x2 tubing and drilled some oversize holes in the ends. After that, I painted them to match the rest of the lathe.

2x2 tubes after painting

These tubes were then mounted underneath the existing mounts to make the feet a little more stable. I made some 0.2" thick washers to help support the weight of the machine better.

Detail of New Foot setup

New Foot under lathe.

Monday, April 21, 2014

Lathe restoration - final push

It has been about a month since the last update. I this time I have been able to get the lathe back into working condtion.

The first job was to repair the chowdered cross feed wheel.
I milled the top flat and drilled and tapped three M3 holes to attach a new pointer. The replacement cover/pointer was made from some 2mm aluminum I had laying around. I used a 45 degree router bit for the chamfer and to engrave the line. The Corners were hand filed to fit.

Before - Looks like somebody ran the compound over the dial at one point

Surface milled and drilled

Indicating in the new cover on my mini pallet

Cover installed on compound

The next job was to install my Phase II BXA toolpost. I just needed to mill the T-nut to fit.

T-Nut after milling - will it fit??

Nice Snug fit :)

A BXA seems to be the perfect size for a Clausing 6300

Plenty of room left for up and down adjustment

Next, I finally got my replacement worm gear. I still needed to make a bushing for one end. Since I didn't have a working lathe yet, I needed to "Turn" the bushing in the mill using my boring head. So I made a V-block soft jaw to hold on to the stock for this operation. I cut a slot in the back of a 2x2x6.5" aluminum block that was just wide enough to fit over the rear jaw in the vise.

V Block showing side walls to keep it from moving

After that, I set up the block on a 45 degree angle and cut the V with a big endmill.

V Block installed in vise.

Now I could start "turning the bushing. After indicating the raw stock, I ran the boring head in reverse to get the OD sized correctly.


OD Turning on the Mill :)

Next, I drilled a 61/64" hole through the part to clear the Leadscrew. The final step was to bore the bushing 1/2" deep to hold the worm gear in place.

Drilling through bronze - only grabbed the drill twice :)

Final fit check - Pass :)

Now the apron can finaly be fully re-assembled.

Something was missing here....

Worm Gear Back In place

Bushing back where it belongs. :)

With the lathe looking like a lathe again, it was time to move everything into it's final place, level the machine and wire up the Variable Frequency drive.

Leveled out in its new home

New home - different angle

All wired up wit control panel prototype

VFD installation inside the base

Final motor mount setup

This will turn into a cover for the base to protect the electrical system.

The current version of the control panel has a Pot for speed control, a 3-1/2 digit digital panel meter as a RPM display, the Start, Stop and Fwd/Rev switches as well as a lit switch that is used as a fault indicator and reset switch for the drive.

Closeup of Control panel

The final test conists of turning down a ~1.75" aluminum bar to check the bed for twist. The fist pass showed about 0.01" of taper over 6" but I was able to get this down to .00015 in a couple of tries. I think I will let things settle for a bit and then test the alignment again.

Test bar - Currently showing .00015" taper in 6"

Saturday, March 15, 2014

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.