Backlash- A simple top hat sleeve modification to the cross slide dial of an engineers metal lathe

Backlash can be caused by wear in the acme thread or its nut, but is also commonly caused by a gap developing between the dial and the sleeve that supports it. This problem is greatly improved by making a sleeve in the shape of a top hat to replace the role of the dial for adjusting backlash. Then the dial can be placed over the sleeve. This is very effective and makes it much easier to set the dial to zero at any time.
Playlist:
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Season 4 Episode 1 of the playlist
"How to use a general engineering lathe" by Evan Lewis (evan-e-cent now evanecent).
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[@David-hm9ic]

OK, I'm only 3 years late. Found you looking for ideas on replacing a lead screw nut. That's a great solution to the problem, Evan. The top hat is brilliant. Wish I had seen this when I was trying to make the dials on my Jet-16 mill-drill adjustable. For future reference, places in the US like McMaster-Carr and Grainger as well as eBay carry Acme threaded rod in right hand, left hand and multiple alloys so it's possible to graft a new Acme threaded rod onto an existing lead screw. For future reference, you might want to use brass rod instead of brazing rod for those little plugs. Brazing rod is usually phosphor bronze and is almost as hard as steel. Try cutting it with a hacksaw and you can tell immediately that it's not brass. Cheers!

[@WinkysWorkshop]

Excellent video! Thanks

[@alistercarmichael4990]

Fantastic. I have followed the threads to get here as I got my AUD 1 week ago and am more interested in pressing her into service than restoration. You have done some wonderful work with the gear train and the obvious weakness of the machine design. Now I only need some stock to progress. Best wishes from Scotland.

[@Evan-e-cent]

Have fun with your new AUD. I have been buzzing mine today. I get my raw materials from scrap metal dealers and have always found them very willing to help by saving stuff for you. It helps if you can impress them by showing them something you made. I obtained 80mm x 600mm solid round stainless steel bar (free), 80 mm diameter x 600 mm solid brass bar, 1200mm x 45mm diameter solid aluminum bronze bar, 1200mm x 30mm diameter aluminium bronze bar, 1000mm x 40mm solid stainless steel bar. These were mainly old propeller shafts from fishing boats in NZ but some from USA. I brought a whole 50lb suitcase of stuff from USA when I flew back to NZ. No problem! That was Jan 2020. Cost about $NZ8= $US5 per Kg. Also from a foundry the risers left over after casting metals: aluminium $NZ7 /Kg but its density is 2.7 compared with copper at 9 and aluminium bronze 8.5. Aluminium bronze is 11% aluminum, 4% nickel and the rest copper. Good luck with getting materials. I think the stainless steel was a lot cheaper per Kg. $30 for the 1000 mm x 40 mm bar.

[@angusbeer4356]

Great minds think alike, I have the same problem with my boxford. To the point the handle drives the dial hard tight and you can't move it. I'm going to order some bronze asap and "borrow" your idea. Thank you sir

[@Evan-e-cent]

Actually the idea came from a casual discussion I found in Model Engineers forum.

[@kieranh2005]

Another Kiwi here! I have a Boxford CUD from the mid 60's, an ex school machine. Didnt come with much so I'm gradually building it up. I built my own cross slide nuts (two, I like spares, steel shell with brass thread insert) and have a spare set of worn out half nuts and some leaded bronze bushings to thread and fix into them. Where you have built this cunning device, I've parted some quite thin brass washers off and slipped them in. I'm also putting electric crossfeed and main feed on, to save the half nuts for threading, and give it the turning capability of the AUD without the cost of a replacement saddle and apron. Cross feed is functional, but I'm having to run it carefully until I can get a limit box to put in before the controller, so if it tries to crash it'll limit itself and switch off at just above a heavy cut.

[@Evan-e-cent]

Hi, If you haven't already done so you might like to look at the software I wrote for setting up the gear train to cut any thread, imperial or metric. I just released a new version a few days ago. It is free and online: www.HeroSteamEngine.com/RideTheGearTrain It has an extensive help / instructions file too. You should find my email address on there. I wonder where in NZ you live. My lathe came from Te Puke High School and I live about a hundred km north. It sounds as though you are getting into some serious modifications!

[@kieranh2005]

@@Evan-e-cent I'm in Dunedin, the lathe came from John McGlashan college

[@Evan-e-cent]

My lathe came from Te Puke High School where my father was the engineering teacher. I was in his class 4 years but didn't get back to lathe work until after he died in 2014 and left me the lathe. A bit sad that he is not still here. See above comments about getting stock. I have installed a variable speed DC motor out of a treadmill $5 from recycling shop. 2.5 HP 4300 RPM. The pulse width modulator speed controller came from China for $67. They have a programmable current limiter which you could use, and display amps and volts. I also fitted a digital RPM readout about $20. I need to make more videos.

[@MountainNZ]

Hi. I've just bought a boxford lathe that I'm in the process of reconditioning. I live in New Zealand too - Auckland

[@Evan-e-cent]

Hi David. I'm sure you will have lots of fun with your Boxford. Have I seen you on the Boxford Users Group? groups.io/g/BoxfordLathe-UserGroup/topic/how_much_patina_should_we/74750562?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,74750562 I am planning another video, possibly too about backlash - How to live with it, and how I made a new cross slide nut by cutting a non-standard left handed internal Acme thread. Bit of a nightmare actually. Do you know the history of your Boxford? I have just written an online computer program for calculating gear wheels to cut threads on Boxford lathes and other South Bend clones: see www.HeroSteamEngine.com/RideTheGearTrain You might find it useful if you have a Model B or C that did not have a lead-screw gearbox.

[@Evan-e-cent]

Hi David. I just heard about a Myford lathe they can't give away.

[@Evan-e-cent]

See the above comments about materials.