Well I really messed up this time.

[Redneck_Sophistication]

Starting to wonder if this machining thing is for me, or maybe just this lathe is cursed.

Now that I’d gone through everything I had a part I want to make with single point threading, now’s the time to learn.

Set all my gears and settings for 14tpi, ran a scratch pass and got half that. Rechecked my settings figured the lower gear selector was off. E/F/G. I needed E for 14 but E gave 7.

Couldn’t figure it out. Drained the gear box of oil do I could see what’s going on inside , something is missing or wrong because I can’t get the output I want.

20 minutes on my knees nose in the gearbox hand turning the chuck to see what way things are moving, I thought I might have figured it out.

Turned the lathe on, not realizing the half nut was still engaged.

Carriage crashed into the chuck before I could stop it. Broke the tool, and snapped the slide of the compound.

I’m crushed.


I might be able to put it back together but who knows if it’ll ever be good or last.

Find one off a scrap lathe??

I don’t know if this is even original as I found the angle markings underneath it when I removed it that were totally blocked when it was installed.

 

[Mcgyver]

Ouch! Must be something in air with two hurt lathes in a day.

What lathe is it? imo how to proceed would depend on how special the lathe was, with the choices being get a big hunk of durabar and start whittling, or go compound-less.

Trying to repair whats there would be my least favoured approach. These parts have to mate properly and I've encountered chill spots after after brazing that made scraping or any sort of fitting impossible. Possible that was in part a procedural error (I didn't do the brazing so don't whether part was properly heated and cooled), but still, its not just braze and carry on. Lots of subsequent fitting required. I'd rather start with a block of cast iron or or just use the lathe without a compound.

Incidentally, the part I mentioned with the chill spot from the braze? It was the bottom half of a compound from my 1968 DSG. Never find one, right? The marvels of the internet came to rescue. I asked on all the machining forums and there was a chap in Alberta for some reason who an extra. He graciously offered it, I got, scraped it in, and carried on with a lathe set up like new.....a thing that would have never happen without the internet....so its not impossible that you'll find one.
.

 

[phaxtris]

That's disheartening for sure

Did you check that you had the right combination of change gears ? Even with a gearbox they still have change gears on the side

You could have a member make you a stand off and run without a compound

 

[Darren]

McGyver has you covered pretty good. If it was mine, I'd make a solid toolpost adapter and ditch the compound but i'd repair the compound for the few times its needed.

To repair it: Its a clean break so it should fit back together fairly accurately. Clamp it tightly and check for alignment. If good, drill and tap for as many 10-24 screws as you can get in it. 6-8? something like that. Then you can Vee out the cracks right to the screws, preheat thoroughly to 4-500f on the BBQ and braze it.

In this case, i'd probably mill off the ears of the tee slot and make a filler plate to fill the entire tee slot brazed and bolted all around. Then surface grind it all flat.

 

[Redneck_Sophistication]

@Darren i like that idea to mill off the ear and replace with a plate that would give better access.

I don’t think I can bolt it together it’s so long and thin. Unless I bolt it to a piece of plate.

I was thinking a ton of clamps on a 1” piece of plate to keep true and preheat the whole thing. Plate would help slow cooling. Wrapped in ceramic wool.

Was also recommended cast iron filler and flux on the redit welding forum. Never used before. And it’s pricey

Run it sticking out so the accuracy or lack there of wouldn’t impact it. Give me a little bit of compound.

Until I could find a replacement that fits.
@phaxtris that is exactly the word I’d use.

As far as change gears I have no idea. Nothing on the lathe says change gears.

I’ve got two selectors on the HS A/B C/D
One on the gear box E/F/G and a dial with 1-11
There’s a metric/imperial selector that does say reverse spur (I think) gear before engaging metric gears.
There’s also a fwd/reverse which is opposite in imperial and correct in metric.

That’s as far as I got before I messed it up.

There is one gear where the change gears are that’s not connected to the others but is on the shaft with the 11 dial gears

 

[Susquatch]

I think we have all been where you are before. A few weeks ago, my wife backed out of the garage with the rear passenger door open.......

You couldn't live in a better place to get great support and help.

I second all the ideas above. Here are a few other thoughts.

A compound is an add-on to a cross-slide. It's usually a couple of t-bolts in some curved slots. You could try to find a BB or whatever brand that is similar. Perhaps post a few pictures of what your assembly looks like and members could suggest some potentials. If you can find a close match, maybe you can order the whole cross-slide from parts and just do an R&R of the top half.

Another suggestion is to build on Darren's idea. But instead of grooving it and filling it with Braze, just use thin epoxy with some bigger bolts than #10. Bolts are typically WAY stronger than cast iron. I don't know your dimensions, but I'd think four 3/8 grade 8 SHCS's would be comparable to the strength of the original solid cast iron - maybe stronger. The weakest link will be the threaded holes in the unbroken part. You might be able to address that with two through holes all the way through the compound for long bolts, and two more shorter ones in the middle. If you tell us the cross-section of that break and the depth of the material available for threaded holes, I would be willing to do a swag analysis for you. (I feel your pain and want to help). One of the benefits of it being cast iron is that it is unlikely that there is any permanent deformation in the rest of the compound. Almost any of the fixes others have listed will get you a solid repair without affecting the long term precision of your lathe.

PS - gotta make slamming that BIG RED E-stop an instinct.

 

[trlvn]

Mr Pete did a 4 part series on building a compound rest from solid stock. He was repairing a 6 inch Atlas lathe so it is not the same as your machine but the general process ought to be very similar:

Craig

 

[phaxtris]

You may have the wrong combination here, that loose gear switches out for one of those no doubt and changes the ratio of the box

I agree with studding and brazing, that's a common repair for cast, braze is similar in strength to cast, has minimal warpage, .I would however not try to weld it, not in a million years, and I have welded plenty of cast

 

[Susquatch]

As far as change gears I have no idea. Nothing on the lathe says change gears.

I’ve got two selectors on the HS A/B C/D
One on the gear box E/F/G and a dial with 1-11

I don't see change gears there either. Your 1 to 11 switch probably does that. I'd be making myself a chart and then comparing what actually happens with what the settings say happens. I'd guess a switch is probably mounted incorrectly or has slipped. I've seen more than one lathe with a slipped dial because it got forced. Most users don't know you have to rotate the head a bit when you move those things so the gears can engage properly. They have no synchro. To be honest, I've never seen a manual that says that either.

That said, It sure sounds like the wrong change gear in there......

 

[Susquatch]

You may have the wrong combination here, that loose gear switches out for one of those no doubt and changes the ratio of the box

The trouble is that I don't see the arms and slides that usually allow gear changes.

Maybe a few more pictures by @Redneck_Sophistication would help.

 

[phaxtris]

The trouble is that I don't see the arms and slides that usually allow gear changes.

Maybe a few more pictures by @Redneck_Sophistication would help.

He says he has a gear in there that is not connected to anything, that would be the on change gear I believe

I'm not an expert by any means, but I have never seen a lathe that doesn't have at least one change gear, usually to get to some obscure threads in the chart, or to switch from met to Imp

 

[Mcgyver]

Mr Pete did a 4 part series on building a compound rest from solid stock. He was repairing a 6 inch Atlas lathe so it is not the same as your machine but the general process ought to be very similar:

Craig

I did a similar job for a new slide rest part for a Schuablin 70.....but I would really encourage Mr.Pete or anyone to get a piece of cast iron rather than use steel. Love the Durabar, it cuts like butter. Not cheap, but hopefully a one time expensive. Terra Nova in mississauga stocks pieces large enough to whittle a whole lathe out of lol.

 

[YYCHM]

I'm not an expert by any means, but I have never seen a lathe that doesn't have at least one change gear, usually to get to some obscure threads in the chart, or to switch from met to Imp

9" SM Utilathes don't have change gears, however they don't cut metric threads either.

 

[Darren]

9" SM Utilathes don't have change gears, however they won't cut metric threads either.

Neither does the SM 1660

 

[TorontoBuilder]

I did a similar job for a new slide rest part for a Schuablin 70.....but I would really encourage Mr.Pete or anyone to get a piece of cast iron rather than use steel. Love the Durabar, it cuts like butter. Not cheap, but hopefully a one time expensive. Terra Nova in mississauga stocks pieces large enough to whittle a whole lathe out of lol.

Sorry to this happened to you. I tend to have similar lapses and always fear something like this happening to me

I second the durabar option. I have used it a few times and it has been my fav metal to work...

IF you opt to replace the compound that is.

 

[garball]

There's no way I'd bother with a repair at this location. If it were non load bearing then sure. Build a new one, it will be a better use of your time as long as you have a mill available. Cast iron is best but you could also go with a block of mild steel and carburize it if you were concerned about surface durability.

 

[DavidR8]

Oh man. I feel for you. But it can be fixed.

 

[jcdammeyer]

Ouch. Sad for you.
Having fabricated a complete Gingery Lathe from castings I really can't see any reason why you can't make a new part. I found that the cast aluminum compound slide just was too soft to work reliably so I ended up casting one in bronze.

There's no reason you can't take your broken casting, with the broken pieces glued on with epoxy and all moving surfaces built up with wax, to a foundry and have them cast one or two out of iron for you.

Likely there are a few metalworkers in your area who would machine it for you once you have the castings. One for practice and one for real hence the need for two...

 

[Former Member]

I can't add much on how you fix this beyond what is already suggested. What I can comment on is how this can potentially happen (whether this is applicable in your case or not is a different question).

Most of us get very used to working with our equipment so much so that we set our settings automatically without thinking.

Throw in a change (new machine, new operation or something), we respond wrong and ........

What should we learn, vigilance in our actions where we are comfortable or stressed and fingers cross not have an experience....

I write this with experience....

 

[Susquatch]

Something that has been bothering me for a while and probably bothers others too....

For most of us, the EStop is on the far left someplace. But we are right handed. Perhaps worse, regardless of handedness, it is counterintuitive to reach nearer to a bad thing to stop it. In my mind, the EStop should be on the right someplace. Or perhaps there should be two or three of them.

When I install a 3phase motor and VFD, I am planning to add another EStop on the right of my carriage.