Are 125mm Diameter Chucks Too Large For The Myford ML7? 

Isn't it good to see Steve Jordan back!

I give the thumbs up before I’ve even watched Steve’s vids. Always very interesting

Lovely to see you back Steve. Another great video.

Great to see you back again Steve. I don't see how the modest additional overhang could explain the movement increasing that much (2 thou to 7 thou). Can only conclude that the larger backplate must be a looser fit on the spindle.

Good to see you back - it's been a while.

Hi Steve Good to see you back as always a very interesting video

Great video. Good demonstration. Definitely found the issue. Thank you for sharing.

Hello Steve, Firstly good to have you back on our screens.... An interesting video, Burnerd made a 6" SLIM 4 jaw chuck for the Myford to reduce the overhang and weight so clearly they thought there was a problem with bigger chucks... I will check back in a few days to see the other comments from your viewers... Take care. Paul,,

Nice to hear (and indeed to see!) from you, it's been a while from your last video 😉

Well worked out Steve

Great explaination, I have found that jaw flex can do the same thing and I use a small narrow slip of paper towards the end of the jaws to fix this , pretty crude I know but works for me. I will now check my boxford as you discribed . Thanks.

Thank you Steve now i Know why my Myford ML7 chatter on deep cuts even after rebuilding the lathe.

Hi Steve. Good food for thought. I get a lot of chatter on my 9a southbend. The 3 jaw that came with it is significantly bigger than the 4 jaw. I’ll look into this. Thank you👍

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I suspect that the spindle is flexing. My sugestion is make a tight fitting mandrel to Place in the bore to make this spindle more rigid.

Good to see another video from you Steve. I’ve copied a number of your ideas for my Myford and I was debating getting a 5” chuck and I think I’ll just stick with my 4” now.

Hello Steve, many thanks for these videos!, I am learning a lot; what quick tool change is the one you are using in this video?

Long time no see 🙈 I wonder just a little bit, have you compared the play or movement of the chucks relative to their back plates? Or the runout of the 125 mm chuck vs. its backplate? Any misalignment combined with the longer hang out could be the cause and not the hangout itself?

I found the same! Thought it was a bearing/spindle issue. I found different tool tips can improve or make it worse.

I'm going to go another route with this, it was mentioned that the self centering 4 jaws maybe out by another comment and this may be the case HOWEVER I would try the exact same cut with a live center also and see if the chatter ends or lessons a large degree, if it does my theory would be an out of balance chuck and that the bearings in the Myford ML7 don't have the ability to control the chuck that far out of balance and would only worsen at higher rpm's, like using a 4 jaw independent chuck and having the object off center you would have to drop the rpm in order to keep the centrifugal forces from taking over. You could test the chuck for out of balance easy enough (do a search on balancing a watch staff) and make something up of your own to test (ground bar and two parallels), it doesn't have to be exact since you are just trying to see if the same side always drops and you know you have a heavy side on the chuck. IF the chuck ends up being out I would probably try to see if there was a local shop that balances drive shafts that could try and bring the balance in a little closer on the chuck for a reasonable price. I have a 6" Atlas lathe and am all to familiar with the weaknesses of the smaller lathe and I have actually ordered a larger lathe now that my skills have grown, BUT having to work around the limitations of having a smaller lathe has taught me how to improvise so there are pro's and cons.

The Chuck might need a balance. I've noticed most factory supplied chucks with a lathe, have balancing holes drilled in the rear of them.

Oh nice content ! I guess you saved me some problems with this video. My lathe also comes with a 100mm chuck and I wanted to use a 125mm 4 jaw chuck but I went with the 100mm. They are pretty cheap on banggood :) I have a question thou. Does it make a difference how I mount my chuck at the backplate ? Because then I have to remember/mark how it was on there before.

I see exactly the same.. Haven't used the 100mm for years, much better thank you

hi Steve, i have the same problem with the 4 jaw selfcentering 5" chuck which i bought from RDG few years back on my myford S7. when i use 6" dia. 4 jaw none selfcentering Burnard chuck i have no issues at all. i enjoy watching your vids.

Many people say no to the idea, but I thought about trying aluminum for a chuck backplate, just seem like the softer material could act as a cushion to stop the vibration/chatter transfer. Any thoughts?

Steve I have just tested 2 lathes I have that have 125mm 3 jaw chucks. One is on a Boxford Lathe and the other on a very old Lorch 5" lathe I have just finished renovating. The Boxford lathe has taper roller bearings at the front and the Lorch has polished hard steel bearings running in cast iron. If I take a cut over 2.2mm deep i.e. 4.4 mm measured on the diameter on the Boxford lathe it is fine and cuts ok. If I make the cut deeper it chatters. I tried the same on the old Lorch lathe and with more overhang and a much thinner spindle I was surprised that would cut 2.2mm deep without chatter if the feed rate was low. The spindle in the Lorch has cone bearings at the front and a ball thrust race at the rear bearing. I suspect the problems with the ML7 chattering is more to do with the plain bearing at the front and the difficulty in adjusting it. The 'Better' Myford 7 lathes have angular contact bearings I believe as the front bearing. I am sure I saw somewhere on the Internet that a ML7 has been converted to such bearings but I cannot find it. John

Have you tried the 125 mm Chuck on the Chinese mini lathe? Was going to get one but funds dried up. With me measuring it, it should fit. Cheers

Are you sure that your 5" chuck is seating properly on the backplate? I'm thinking that perhaps you have a sharp corner contacting an internal radius or suchlike. I thought the 2 thou play at the rear didn't scale up linearly to 7 thou at the front indicated that there was some flexing in the chuck mounting.Hope it helps, Andrew

What would be the best recommended 3 or 4 jaw non chinese chuck to use on a Super 7 Small Bore lathe?

Hey Steve, good to see you're back! I was afraid you were slain by the virus.

I think there is something else going on here besides the larger stickout, though I can't really be sure what. All else being equal, the deflection you see with that static lateral load test should be proportional to the distance between the front bearing and the measurement point (there will also be deflection due to rear bearing play, that would be proportional to the distance to the rear bearing and so would vary less with position). Yet with the larger chuck you are seeing more deflection even when you measure at pretty much the same location as you did with the smaller chuck. Also, due to the dead weight of the chuck I would expect to see most of the deflection when you pull up on the rod, and that its unloaded position would be at the bottom of the range of play, yet it seems to deflect more with downward force that with upward force. It is difficult to tell from your test what is play in the system and what is elastic flexing of the system.

If it's not the chuck flexing it's the.... Chuck to spindle engagement Head stock bearings The extra mass of the bigger chuck should help, rather than hinder, if anything.

The Myford ML7. Is it hard to get one of these in Europe? I like the look of these Lathes and I'm trying to get a decent sized lathe but thee would really only be for lighter work?? Ok so they could always do certain types of jobs I know and they're a well thought of Lathe from what I have seen online but my main question is are they expensive to buy even with a fair bit of work needing doing to one??

I never thought it was a thing until i seen Winky's Workshop done videos on it, it's amazing, quite the opposite to what you would think, i would of thought, bigger Chuck more mass etc, but no.

The back plate I think is the problem, given you the extra lenght. Just measurded my 150mm adjustable 4 jaw chuck, from the back of the chuck to the tip of the jaws= 67mm. The 100mm = 74mm.

This is why the likes of Sieg on their mini lathe only fit an 80mm chuck still, they say a 100mm chuck is to big & to heavy for those size lathes. Where as other Chinese mini lathe suppliers are now fitting 100mm chucks as standard now.

Can you compare your results with someone who has a newer model ?

I would like to see on test on the spindle and another set on the chuck as close to the inner diameter as you can get. May prove if the issue is in the spindle fit or the movement is all in the bearing clearance.

I am interested in your oil cup nozzle on your oil can mate

You're comparing a 4 jaw self centering with a 3 jaw self centering, two different animals. If you compare the run out visually at 7:30 (4 jaw) and 10:23 ( 3 jaw) , You'll see the 4 jaw is way off center. I never use 4 jaw self centering chucks. Not saying that's your problem at all and doesn't explain your runout when indicating it, but well it's a thing to be aware of. The 4 jaw self centering will always find an axis when clamping down. You could also be experiencing runout in your backplate, maybe there's a burr in there or the register is off? The amount of movement you are getting when you indicate it just seems really extreme to me. You can visually see the whole thing move were the backplate meets the spindle, which seems like a fitment thing? I know the larger chucks have more weight and stickout and that's definitely something to be aware of as well, but I use a 5" 3 jaw self centering bison on my ML7 and don't get chatter or runout like you are getting. Maybe's it's a fit and finish thing as well? HBM VS Sanjou. I've never tried either of those before.

Hi Steve. Not sure if you have seen any of my video's. I have the Super 7B. The 3 jaw is a pratt 4" griptru. Superb chuck & very accurate. The 4 jaw as supplied with the lathe is a pratt, independant. But it is only 4 1/2" dia & 2" deep. I have had no such problems with either chuck. The one you have looks awfully deep. I guess much heavier than the ones supplied new. Regards

I swear I heard an Owl hooting in the background, do you start that early in the day?

If the chuck adapter is cast iron, you may want to make a steel replacement and see if the adapter is flexing. If the unit you are using is of unknown mystery metal, it may just not be ridged enough

your lathe was bouncing when u were bringing the bed away from the piece in the chuck. What type of bench or surface do u have the Lathe up on pal? Maybe some type of concrete blocks under a strong table top so u could somehow screw or bolt the Lathe to it might help also. The Lathe was flexing like mad when u ere moving the tool bed/rest/bed back along the ways.. Sorry if I am sounding stupid man but I saw ur Lathe bouncing up and down like it was on a load of springs.

Any recommendations on a quick change tool post Steve

Interesting you did not use the long bar on the smaller chuck and measure it's movement. I assume the larger chuck seats well on the spindle? Larger chuck just magnifies the bearing clearance.

I agree with John Barber. The increase in deflection of the 5” chuck is not proportional to the small increase in overhang. I suspect there is an issue with the chuck mounting, ie it is not solidly registering and there is some clearance at the joint.

Interesting.

I find the opposite to be the case. I get chatter with my 4 inch 3 jaw Chinese chuck but not with my 5 inch Burnerd 3jaw or my 6 inch Burnerd 4 jaw. I assume it is the quality of the chucks that makes the difference.

et si vous serrer plus fort votre plaque arrière sur la broche ? même résultat ?

The chuck is bigger than the headstock no wonder.

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I'd try different types/size belt set up

Mass V diameter Weigh both chucks Steve... I bet 1" increase in ∅ returns an over 50% increase in weight...