Monday, August 29, 2016

Fixing Worn Out Cross Slide Screw for a 1906 Rahn Mayer Carpenter Lathe

Difficulty Level (Easy, Medium, Hard, Insane):

A gentlemen in town contacted me about this old 1906 Rahn Mayer Carpenter metal lathe he had with a worn out cross slide screw so I had a look at it and even though the female part was bronze, both, the female bronze as well as the iron male part of the screw were completely worn out to the order of almost 0.100" slop.

Needless to say, he experienced some chatter when using the lathe. The cross slide screw looked like it was a left-hand, 3/4" diameter, 8TPI screw with a square thread. I told him that unfortunately I wasn't equipped to cut that type of thread, but what I ended up doing was to cut off the existing thread, turn it down to 9/16" and cut a regular 60 degree, 8TPI thread into the rod. Then, I cut off a 3" piece of 1" brass, turned it to down to 7/8" diameter, drilled a 7/16" hole and used a custom tap I had made out of O1 tool steel just for this purpose.

Then, I drilled and bored the worn out female thread of the brass piece and press-fit the new bushing (with the internal 9/16" by 8TPI thread) into the existing bronze part. All that was left was to cross-drill a 3/16" hole through both, the original bronze part and press in a roll pin to lock the new brass bushing to the bronze part.

Originally, I was going to use regular mild steel for the bushing but because I made the tap out of O1 tool steel, and because the 8TPI threads were quite coarse, I opted for using brass instead. In retrospect, I'm glad I did because I don't think my tap would have been strong enough to cut through mild steel.


Close-up of the name tag and gear ratios
The cross slide taken apart
The cross slide knob
The old screw and block
Another view
Close-up of the banged up woodruff key
After the cross slide screw and handle were taken apart
Removing the existing worn thread
The old thread almost gone
Another view
Starting to cut the new thread
The finished screw
Close-up of the new thread
Another view of the cross slide screw
Another view
Close-up of the worn gear in the bronze block
Getting ready to cut the thread in the custom tap
Another view
Milling the relief cuts into the tap
Close-up of the relief cuts
Cleaning up the threads after the relief cuts were made
Another view
Done and ready for heat treating
Heating the tap in the propane burner
The hardened tap, ready for tempering to light straw color
The finished tap
View from the bottom
Side view of the finished tap
Cutting 3" of 1" brass stock
Facing the end and center drilling it
Turning the stock to size
The brass piece turned to 0.870" and drilled to 7/16"
Getting ready to tap the left handed 9/16" by 8 TPI thread
About half-way done
The finished bushing
That on the left will have to go into that on the right
Boring the hole to 0.868"

The finished brass piece ready to be pressed into the bronze block
Aligning the drill to hit half of the bronze block and half of the brass bushing
You can see the difference between the bronze and the brass
After a 3/16" roll pin was inserted to lock the brass bushing into the bronze block
The finished piece

Metal lathe and accessories
Metal band saw
Propane burner
Dividing head
Adjustable wrench
Oxy/Acetylene torch
Parts washer
Alan keys
Wire brush
Belt sander
Hand file
Drill bits
Angle grinder
Eye & ear protection
Bench vise

3" of 3/4" O1 tool steel
3" of 1" brass
3/16" roll pin
2L of old motor oil


12 hrs

It looks really nice and there's zero slop in that screw now. I'm sure he'll be happy to be able to use his old lathe again

Sunday, August 28, 2016

Making a MIG Welder Cart

Difficulty Level (Easy, Medium, Hard, Insane):

In my research for my upcoming DIY backhoe building project (blog to follow) I came across a gas powered pressure washer whose pump had died. After I took off the engine and accessories I was left with the cart which I used to build a MIG welder cart.

The first thing I had to do was to take off the metal piece that the engine was bolted onto, flatten it out and bolt it back on the frame a bit higher up. Then I had to make two support "legs", bolt those to the metal shelf.

The last thing was to make a holder for the Argon/CO2 tank which I made using some 1/8" x 1" flat bar, some 1/8" flat metal and a couple of small chains I had lying around.

Now I can wheel the welder around much simpler than before when I had to drag the individual pieces and set it all up again at its final location.

The pressure washer (broken pump manifold) I picked up on kijiji for $35 bucks
The cart after all the pressure washer components were stripped from it
Another view
After I straightened the metal shelf and mounted it higher up on the cart
The welder sitting on the metal shelf
Close-up of the two legs I added (parts from an old treadmill)
The bolt holding the metal shelf towards the front of the cart
Using two pieces of 1/8" flat bar to hold the welder to the cart
Getting ready to make a bottle holder under the welder
Getting ready to tack weld the bottle holder
The finished welding cart
Side-view of the welding cart
The bottle holder under the welder
Rear view of the bottle holder
Another view
My MIG welder finally has a permanent home
Another view of the cart
Metal band saw
MIG welder
Angle grinder
Drill press
Measuring tape
Pencil & marker
Socket set
Screw drivers

5' of 1/8" x 1" flat bar
2' of small chain
6" by 8" of 1/8" flat metal


3 hrs


I love it! It works really well