Myford ML7 Resurrection - A New Summer Project

[gerritv]

Based on experience, don't discount ordering from UK, quite often the shipping from there is less than from US. And esp. if it involves UPS. For some reason UPS from US attracts a lot of fees. And factor in fuel cost, I wouldn't consider your loation close to US border
Just make sure you don't pay the 20% VAT in UK, that offsets much of the shipping cost. The link that was posted has extremely reasonable shipping prices from UK.

Also from observation using an optical comparator, not all BA hardware is 47.5deg. I have a set of Pratt&Witney taps/dies (so presumably quality) and they are all 55deg thread. Maybe verify yours with a USB microscope or such? You can buy 55deg threaing inserts from AliExpress but that won't help with making nuts.

Gerrit

 

[WobblyHand]

Based on experience, don't discount ordering from UK, quite often the shipping from there is less than from US. And esp. if it involves UPS. For some reason UPS from US attracts a lot of fees. And factor in fuel cost, I wouldn't consider your loation close to US border
Just make sure you don't pay the 20% VAT in UK, that offsets much of the shipping cost. The link that was posted has extremely reasonable shipping prices from UK.

Also from observation using an optical comparator, not all BA hardware is 47.5deg. I have a set of Pratt&Witney taps/dies (so presumably quality) and they are all 55deg thread. Maybe verify yours with a USB microscope or such? You can buy 55deg threaing inserts from AliExpress but that won't help with making nuts.

Gerrit

I've ordered things from the UK and survived
You simply have to watch out for the total cost. If the total cost is within your comfort zone then there's no issue. But do get tracking.

I don't know where one might find BA inserts, but it's not hard to grind a piece of HSS to that profile. One could even start from a 60 degree thread profile and make it "sharper".

 

[gerritv]

Living in Canada we are used to checking cost of shipping. From US is usally the worst so I personally avoid that option. UK can be good, EU in between and from Asia is inexpensive.

For 55deg inserts I have used https://www.aliexpress.com/item/1005003765619821.html I buy from that store frequently. If you puzzle through the nomenclature and backtrack via https://www.machiningdoctor.com/grades/ you can determine the manufacturer. I am confident they are the real thing based on actual appearance of the tray, use and wear.

gerrit

 

[SightlessSeer]

Living in Canada we are used to checking cost of shipping. From US is usally the worst so I personally avoid that option. UK can be good, EU in between and from Asia is inexpensive.

For 55deg inserts I have used https://www.aliexpress.com/item/1005003765619821.html I buy from that store frequently. If you puzzle through the nomenclature and backtrack via https://www.machiningdoctor.com/grades/ you can determine the manufacturer. I am confident they are the real thing based on actual appearance of the tray, use and wear.

gerrit

I have already ground a 55° HSS outside threading tool. I picked up a 55° fishtail gauge a while ago from my local tool store so grinding 55° tools isn't an issue for me (also I don't have any carbide tool holders). If I really have to cut some BSW or BSF internal threads I can grind an internal tool, but for now I'm keeping my fingers crossed.

I'm still holding out a naive hope that I have managed to dodge the whole BA bullet.

 

[SightlessSeer]

Finished up the gib today. I think I'm going to have to mess with the dimples in the gib. As is, I have it properly tight and moving freely for the most part, but if I move it around enough it will bind and I think that is because the gib is moving relative to the gib screws which wedge it tighter into the dovetail. For now it's good enough though. There's a slightly tight spot in the cross slide at the end of travel, but nothing major or unexpected from a lathe of this age/condition.

Spoiler: Pictures

I don't have pics of much of the roughing out process, but I did eventually turn my reclaimed cast iron into something usably flat. I'm not going to worry too much about scraping or grinding it in or anything. I don't think that this lathe is in the condition where it will matter.

Here I was still trying to figure out how I was going to fixture the gib to cut the relief at the top and bottom. I have seen a video or post somewhere of somebody doing this with the cross slide itself as the fixture and that made sense to me.


This is the setup I ended up using. I've seen people using adjustable parallels for clamping the gib before, but I didn't have one that worked well here, so I made do with some bolts and random spacers.

I kept the cuts light (under 0.010") and the milling went fine.




Once put back together and adjusted a bit everything moves freely and is tight

With the gib finished, I'm fast approaching the point where I need to make a choice about what I'm doing for spindle bearings. I would still love to do a timkin bearing mod, but I'm not sure if that's going be viable. If it isn't I might try turning my hand to pouring babbit. Not something that I've done before, but it could be fun. I have no idea where I would source the metal from though. I would have to do some more research on it. As was recommended to me, Keith Rucker has some solid videos on babbit pouring and it doesn't look very hard. My main concern would be in making sure that everything is aligned properly before hand. Although realistically, if I go the Timkin route I'll probably need to realign the headstock anyway.

Anyway, those are just some of my musings on options. Feel free to chime in if you guys have any suggestions. Another thing that I'm wrestling with is whether should I repaint the lathe or not. It would look 100x better repainted, but I _hate_ painting with a burning passion. That's future me's problem though.

 

[SightlessSeer]

Finished up the gib today. I think I'm going to have to mess with the dimples in the gib. As is, I have it properly tight and moving freely for the most part, but if I move it around enough it will bind and I think that is because the gib is moving relative to the gib screws which wedge it tighter into the dovetail. For now it's good enough though. There's a slightly tight spot in the cross slide at the end of travel, but nothing major or unexpected from a lathe of this age/condition.

Spoiler: Pictures

I don't have pics of much of the roughing out process, but I did eventually turn my reclaimed cast iron into something usably flat. I'm not going to worry too much about scraping or grinding it in or anything. I don't think that this lathe is in the condition where it will matter.

Here I was still trying to figure out how I was going to fixture the gib to cut the relief at the top and bottom. I have seen a video or post somewhere of somebody doing this with the cross slide itself as the fixture and that made sense to me.


This is the setup I ended up using. I've seen people using adjustable parallels for clamping the gib before, but I didn't have one that worked well here, so I made do with some bolts and random spacers.

I kept the cuts light (under 0.010") and the milling went fine.




Once put back together and adjusted a bit everything moves freely and is tight

With the gib finished, I'm fast approaching the point where I need to make a choice about what I'm doing for spindle bearings. I would still love to do a timkin bearing mod, but I'm not sure if that's going be viable. If it isn't I might try turning my hand to pouring babbit as kevin.decelles suggested. Not something that I've done before, but it could be fun. I have no idea where I would source the metal from though. I would have to do some more research on it. As was mentioned, Keith Rucker has some solid videos on babbit pouring and it doesn't look very hard. My main concern would be in making sure that everything is aligned properly before hand. Although realistically, if I go the Timkin route I'll probably need to realign the headstock anyway.

Anyway, those are just some of my musings on options. Feel free to chime in if you guys have any suggestions. Another thing that I'm wrestling with is whether should I repaint the lathe or not. It would look 100x better repainted, but I _hate_ painting with a burning passion. That's future me's problem though.

 

[SightlessSeer]

I think I've decided what I'm going to do about the bearings. I'm going to go with a similar modification to the spindle to the one by Wolfgang in the link I posted earlier (see below).

I actually found a thread where somebody did exactly this after a quick google.

Since I knew that the bearings were previously replaced, I wanted to disassemble the spindle so I could take some real measurements.

Spoiler: Disassembly

The spindle was pretty stubborn to get apart. I ended up putting it in the oven for about an hour at 350 F then setting it up in the vice as shown above and driving the spindle out from the rest of the parts. The black plate on top was to prevent damaging the back of the spindle with the hammer.
The oven mitt here is because the spindle was still quite hot.

This sleeve at the rear of the spindle was labelled Torrington and had the part number IR151816. Turns out that it is the inner race for a needle bearing. I didn't get the bearing with the lathe, but that seems like a reasonable choice for this application

To accommodate the needle bearing, a previous owner turned down the rear section of the spindle from ~1" down to 15/16". This really eats into the threads for the tensioning collar at the rear of the spindle. There is enough there to thread it on, but I definitely don't want to take it down any further.

I modelled up the spindle in CAD and started looking around for bearings that would work both with limitations of the spindle and with the limitations of the headstock casting. The two main constraints here are is the gap between the screws for the bearing caps. This rules out the vast majority of bearing options. The next constraint is that the step that the backgear and pulley run on is 1 1/8". Unless I wanted to massively complicate things I cannot go with a bearing with a smaller ID than that. With those two constraints the only combined thrust and radial load non-plain bearing that I could find was the tapered roller bearing that Wolfgang spec'd for his mod (L45449/L45410). The ID is 29 mm and the OD is 1.98".

For the rear bearing I would have loved to once again followed Wolfgang's lead, but with the reduced section on my spindle, his selection will not work for me unless I sleeve that section back up to 1". Looking around, I couldn't find any options for the reduced diameter of 15/16" for the ID of the rear bearing. Resigning myself to the reality of sleeving the spindle, I figured that I might as well use the same bearing for the rear bearing as the front one. As a bonus, L45449/L45410 bearings are only $10 each.

Here are some pics of my plan of attack.

Spoiler: CAD Model

This is the current state of my spindle. It is more or less the same as OEM with the exception of the second last step from the rear, which has been reduced to 15/16" from 1". There is a short section in front of it which is still the original 1" bearing surface.

This is what I propose to modify my spindle to The only difference is reducing the front bearing's step from ~1.25" down to 29 mm (1.1417"). This is the same modificaiton that Wolfgang made to his spindle.

Please excuse the black background here, but this is my planned assembly. The grey sleeve's position is approximate so take that with a grain of salt. Also keep in mind that I'm going to need to add at least 4 spacers. to take up the excess spaces where there used to be bearings.

To accommodate the new bearings, I'm going to have to bore out the headstock castings, and find some way to lubricate them. I'm thinking that The spacers on either sides of the bearings could have o-rings on the inner and outer surface to make a sealed-ish reservoir to hold enough oil to keep the bearings lubed.

Let me know what you guys think about this, especially regarding lubrication. I really think that tapered roller bearings are the best option and will end up with the cleanest result in the end. One thing that I don't love is that the sleeve under the rear bearing will have to come off if I want to completely disassemble the spindle. I think I should be able to take it out of the lathe without totally disassembling it, but getting the back gear and pulley off will definitely be a problem.

Anyway that's enough rambling for the time being.

 

[SightlessSeer]

Quick update. I've decided that it'd too cold in my garage to work on this at this point. I'm planning to bore the headstock casting out for the new spindle bearings on my mill, but first I need to make a custom boring bar to use for line boring. I have the stock (both HSS for the cutters and regular steel for the bar itself, but It's cold enough up here that I don't relish the idea of working in my unheated garage. I'm going to wait to finish up the bearing replacement until spring (or maybe until a warm snap).