Tooling size for myford ml7?

Ive just got a myford ML7 that needs a bit of TLC.

Im wanting to machine some new feedscrew nuts and replace the threaded feedscrews for a start.

I have bought a bunch of 8mm tooling on ebay, but its not high enough to centre the tip of the tooling, I have clamped down the tooling on top of a second 8mm tool and it brings it fairly close to centre, but even then, I could do with a fair bit of shimming.

Im assuming Myford originally used imperial tooling? I get the feeling 16mm tooling is not the correct size either.

I intend on getting a quick change toolpost soon, and I think they are designed for 8mm tooling to bolt straight in?

I also am not sure about the correct way to mount a boring bar. I have an 8mm boring bar I want to use on some projects.

I see these holders here on aliexpress.

https://www.aliexpress.com/item/32851566841.html?spm=a2g0o.cart.0.0.52e93c00ab3jsJ&mp=1

What would be the correct size for a myford? 20x20mm or 16x16mm?

Im hoping I can get these feedscrews sorted soon, biggest problem is that they are so sloppy that i cant even face off cleanly without the topslide moving on me while cutting, I end up with a dome shaped face instead of something nice and flush.

Standard Myford 4 way toolpost takes 3/8" square tooling. That's about 9.5mm. You can use 8mm quite successfully by packing it up with suitable flat steel packing strips cut from sheet or flat bar etc. If you use modern 10mm carbide insert tooling you will need to machine a bit off either the bases of the tooling (very tough) or off the bottoms of the toolpost slots.

8mm boring bar is held the same way, clamped in the toolpost sitting up on packing strips to get tip to centre height.

If you have the earlier single tool saddle clamp arrangment, 3/8" tooling would have been standard, sat on suitable packing strips.

Edited By Hopper on 11/05/2020 06:08:00

My lathe basically has the early saddle clamp that you tighten the nut down to hold the tooling in place as you say.

3/8" seems like it would be too small on my lathe.

How i have it set up as if I was using a 16mm tool currently and its about 2mm too high after a closer inspection.

My guess would it needs to be about 14mm high.

I will grab a photo so I can show things in more detail.

They used 3/8" tooling on them. Solid HSS on packing. It was crude.

If you get a QC toolpost it will be to take 8 or 10mm tooling. Others on here can share their QC experiences. I only use the old 4 way.

I was looking at 4 way too. IDK what is best, but QC seemed a good idea.

Here is a photo from the back of the lathe.

Its 16mm high in this photo (essentially using another 8mm tool as a shim)

Looks like it needs to be dropped about 1-2mm to make it on centre.

Yes looks like it needs to be dropped a bit. You can use any strips of steel for packing. Bit of 6mm flat bar and bits of thinner sheet metal for fine adjustment might do it.

I don't mind the four way toolpost myself but it seems the QC ones are popular these days but you have to make sure you get the right one. Not all are great quality and not all fit the Myford well.

1/4" HSS is plenty for a Myford, cheaper and easier to grind than 3/8". Picture shows an arrangement that I copied from a Myford owner and used  for years on my Boxford. Cheap as chips. With a selection of home-made holders, tool changing takes seconds. The packer for the Boxford is a piece of 1/4" plate, about 2.5" sq. with a hole drilled for the tool-clamp stud, but might not be needed for the Myford. I later replaced the clamping nut with a permamently mounted handle.

Edited By Clive Brown 1 on 11/05/2020 08:55:18

That angled holder looks a brilliant idea, would make it super easy to get a perfect centre.

Is there anywhere you can buy these? Im assuming you milled yours out to suit?

I remember being confused by lathe tool-sizes too! I assumed that lathes took a particular 'correct' size, but it's rarely so.

All that matters is that the tool can be gripped by the holder with the cutting point at centre height. Oversized tool-shanks are a difficult problem because they have to be reduced to fit. Not worth the bother in my opinion!

Some tool-posts are adjustable. The American's once favoured a sort of tilting boat affair; never used one myself but they're criticised for being fiddly to adjust and not very rigid.

These days, the 4-way tool-post is common. It's a simple flat platform, pretty solid, and tool height is adjusted by shimming under the the tool, as shown in Shaun's photo:

Same idea except I have a collection of shims up to 4mm thick made in a milling machine, short lengths of 1mm steel strip (as used on big packages), and various thicknesses of aluminium strip. For thin shims, cut-up Aluminium Drink cans. I mostly use carbide inserts, and keep a set of pre-sized shims ready to go with each tool; this makes a 4-way tool post almost as fast as a QC type. As always much depends on how you work; frequent fast tool-changing in an HSS shop shouts 'QCTP'. But many HSS users do almost everything with one tool - a tangential tool-holder - see Eccentric's ad on this site. I've not bothered with a QTCP because ready to go shimmed tools are fast enough for me and because the tool does not need to be removed from the lathe for sharpening - changing inserts doesn't mess with the height setting.

The photo shows a second beginner booby trap. Those painted carbide tools! I had nothing but trouble with mine, and it turned out to be because they're not necessarily sharp out of the box. Being carbide, they can't be sharpened on an ordinary grinding wheel, and sharpening skills are needed. Another problem is carbide performs best on fast powerful machines, which the ML7 isn't! So, quite easy for a beginner to get poor results and assume his lathe is at fault, when it's just the cutter. Problem multiplied if a beginner also starts by cutting random scrap metal from his junk box because a metal-lathe will cut metal, right? No! Many metals don't machine well, and quite few are vile. DIY store metal is generally poor. Best to start with metals bought because their specification mentions free-cutting or machinability. EN1A-Pb steel, most Brasses, or an appropriate Aluminium Alloy.

Dave

Do yourself a favour and get 8 mm tooling, for all the above reasons. As far as QCTs are concerned , hold fire. I tooled up my ML7 and ML10 with the type that "old" Myford supplied. The subbie that made them for Myford, occasionally does runs of them. Excellent quality and not quite outrageously priced.

Years later, when I wanted to do some precise, repeatable work, I had problems. Turns out that even good quality QCTs were not all that rigid.! I finished up with a GHT 4 way toolholder. Much more accurate than any QCT I have used and cheaper to boot.

Newcomers seem to have the idea that QCTs are "fashionable" and desirable. It isn't necessarily so!

Andrew.

Do yourself a favour and get 8 mm tooling, for all the above reasons. As far as QCTs are concerned , hold fire. I tooled up my ML7 and ML10 with the type that "old" Myford supplied. The subbie that made them for Myford, occasionally does runs of them. Excellent quality and not quite outrageously priced.

Years later, when I wanted to do some precise, repeatable work, I had problems. Turns out that even good quality QCTs were not all that rigid.! I finished up with a GHT 4 way toolholder. Much more accurate than any QCT I have used and cheaper to boot.

Newcomers seem to have the idea that QCTs are "fashionable" and desirable. It isn't necessarily so!

Andrew.

I milled most of mine using a vertical slide, which incidentally I'd much prioritize over a QCTP if a milling machine wasn't in prospect.

The angle does give "micro" height adjustment but also gives top-rake with minimal grinding, so tool-bits can last longer.

Material is 5/8" x 1" BMS.

Round hss for boring tools can be catered for by drilling the toolholder whilst clamped on the top-slide.

Armstrong pattern holders

Interesting read thanks Dave, I was not aware of such drawbacks with the QCTP, but I think some of it comes down to the quality of some brands I guess?

What seemed attractive to me was it made it hassle free to change the height and centre the tools etc without shimming up to suit. I probably could get away with a 4 way tool post, and perhaps I might just settle on that for now. One thing I can say for sure is I get tired of unclamping the tools and then bolting a new one back on!

Im still unsure why my height is so different on this lathe, if it should be closer to 9.5mm(3/8"?

I have measured a little over 14mm currently.

I was aware that these cheap carbide tools are nothing spectacular, I just grabbed them to test the lathe until I know what type of tooling is best.

I didnt know at the time that carbide required so much RPM to operate on either, and there seems to be a debate over HSS vs carbide for the quality of your finishing cuts. I had been reading a fair bit on this subject recently and seems it works best at a higher RPM as you say.

What I can say is I have tested these cheap tools on aluminium and i got a super smooth finish, my neighbour who is an engineer gets me scraps from his work and told me that aluminium needs to be turned at really high speeds for the best results which is interesting to hear.

Either way, I will probably add a VFD driven motor as an upgrade in future and get more RPM out of this when I get round to refurbishing the lathe.

Regarding HSS tooling, it seems everybody is grinding their own tools, I dont have any experience in doing this and find it hard to see how an ordinary bench grinder can do this? Im assuming you need a real fine grindstone?

As far as tooling goes, most that i can find seems to be carbide, particularly when it comes to thread cutting tools and boring bars that use the inserts.

I quite like the idea of inserts, can you get HSS inserts instead of carbide?

.

Don’t over-do that speed increase ... The ML7 bearings may not last long

MichaelG.

OK, well I think my one is underpowered, i have an old 1/3 HP motor running on it currently, wouldnt say its the fastest. Seems a few youtubers have a fancy setup with a VFD, but not sure what speed they are running.

1/3 HP is plenty for an ML7, I ran mine for many years with 1/4 hp. If you go for vfd eventually you'll need a bigger motor because power drops as you wind the speed down. I think the Myford recommended top speed was somewhere around 700 rpm, but I'm open to correction.

Not sure of which model ML7 you have , but assume it is the same as the super 7. This is the rating plate of my Super 7 B.

Steve.

Posted by Shaun Belcher on 12/05/2020 01:32:37:

If im reading this correctly, is that saying 2105 RPM is the top speed on a 50hz power?

From memory my ML7 was made round 1956 going by the serial number.

IDK what the story is with the white metal bearings, but they appear OK, certainly dont want to wear them out, but my neighbour tells me that his place of work is one of the few places still making white metal bearings/bushings.

Edited By Shaun Belcher on 12/05/2020 01:37:30

sorry double post by mistake

Edited By Shaun Belcher on 12/05/2020 01:35:24