Emco FB2 Quirks and Additions

[Kiwi BlokeParticipant @kiwibloke62605]

… If it turns out that the quill bore and the bore for the vertical column can't be adjusted to be parallel, there's a real problem, isn't there? …

Sorry, badly expressed – there is no adjustment provided to correct this, but, of course, the head swivel faces can be scraped…

[mgnbukParticipant @mgnbuk]

Did you check the parallelism of the table top to the base casting (Y axis ways) ? Depth mic from four points from the table top to the base should give 4 near identical readings & 4 micrometer readings of table thickness should show that the table top is parallel to the X axis ways. Though as you have set the column square to the table top, the spindle trammel check suggests that the error is in the head casting joint – checking & adjusting each interface from the base casting upwards is the way that CNC machines were rebuilt at my previous employment. Knowing each stage is "right" as the machine is assembled makes it easier to track down errors as the build progresses.

When it came to getting machines accepted after a rebuild, it was usual to work with the tolerances in checks – could you bias the column slightly off square to improve the trammel check ? You say that the column is within 0.01 over 180 mm – tweak it so that the 0.01 goes the opposite way & if that improves the trammel it is an overall improvement ?

If you have a surface plate & 2MT test bar, take the quill carrier casting off the machine, set it on the swivel surface on the surface plate & check that the test bar is parallel (alignment of swivel face with spindle axis). If this is OK, it suggests the error is in the swivel face on the Z axis casting. If not, scrape the face to correct the error & re-check, though it may be that the error is split between the two faces. I don't know which casting has the location spigot, which can complicate doing this check – may require making up a parallel ring to get the spigot clear of the surface plate.

I don't think that these machine would have had much in the way of fitting – the selling price would not allow that & what you are seeing doesn't seem to be that far out to me for this class of machine. I set the column square on my Taiwanese clone much as you have done, though I used a 150mm precision square rather than a cylinder square, and shimmed the column carrier casting as you did to get the front-back squareness. This is another joint that should really be scraped to remove the errors, but that is still on my "Round Tuit" list as the shimming doesn't seem to be causing any issues. With the column set as close as I could get it in both planes the trammel check came out "close enough", though I can't recall the exact numbers. "Close enough" being that I didn't feel the effort involved in removing the last few microns was a worthwhile use of time & the results from using the machine as it is have been acceptable for my requirements.

Nigel B..

[Jim CParticipant @jimc]

Joseph. I have what I suppose you would call an FB2 clone in the guise of a Rishton mill (not many about by all accounts) I set the head square in the usual way using an extended DTI in the spindle and checking the table at two extreme points.

You talk about doing some accurate deep boring on your mill. I am interested how you do this on a mill that has a very small quill movement and a circular column. To date I have not had a job where I could not use the lathe to do the boring and would be a bit reluctant to unlock the head of the mill and use that to bore with. I’m worried that the head will move slightly on its gib strip ??

Interested in comments from FB2 or similar mill users.

Jim.

[Graham MeekParticipant @grahammeek88282]

Hi Joe,

I have just read your post concerning the out of vertical on the column.

I would be inclined to take the head off the column. Then present the cylinder square to the exposed mounting face on the Column Slider casting. I would try with the Lock/Clamp On and Off.

If there is no error, move the Slider out of the way and offer the Cylinder square to the Column. You will need to raise the Cylinder square for this test on some known good parallels. As the Column casting spigot is above table height.

If you have parallels long enough these could be extended such that the Cylinder square can be presented to the side of the Column at the same setting. The parallels would need to be lightly clamped to the table to counteract the weight of the Cylinder square.

Provided no adjustment is needed, I would then mount the milling head on the milling machine table. Again you will need some parallels to miss the spigot on the rear mounting face. With a DTI mounted in the spindle swing over the Cylinder square. This test will prove the squareness of the mounting face. Remove the Cylinder square and insert a No 2 Morse test Mandrel in the spindle. Run a clock over the exposed plain portion. This will check the parallelism of the Quill/Spindle to the mounting face and verify the above squareness check.

Some Silver Steel held in a collet and set such the any run-out is at 90 degrees to the reference test will suffice for the above test.

My machine spindle dips 0.02 mm when the Column lock is released, given the overhang I can accept this. My Column adjustment is done off the machine and in use it needs to fall under it's own weight, ie, with milling head attached. Having it too tight means you get stick/slip and sudden un-explained amounts taken off.

With the Column lock on the Tram North-South is -0.01 N to +0.01 S, this is over 200 mm. East-West is Zero-Zero.

Hope these notes help.

Regards

Gray,

Edited By Graham Meek on 04/11/2020 16:52:21

[Joseph Noci 1Participant @josephnoci1]

To:

Kiwi Bloke, Nigel B, Jim, and Graham.

Thank you for all the suggestions and advice. I spent the day yesterday working on this and used a combination of suggestions and test methods and now have the mill nicely within acceptable tram limits.

I first worked on setting the 'nod' on the head assembly – I used an MT2 Test bar as suggested by Graham – Set in the spindle. the test bar parallel section is 250mm long, runout in the spindle , at the spindle end of the bar is barely evident on the DTI. At the end of the bar, furthest from the spindle, runout is half a division on the 0.01mm DTI. I set the DTI base on the column, with the DTI tip on the bottom of the test bar in North South pose, ie, to check parallelism between column and test bar when running the head up and down.

North South Nod

This resulted in a half circle shim 0.008mm ( as close as I can read..) inserted in the lower hemisphere between the column sliding casting and the mill head casting. The shim extends to within 20mm of each bolt ( one left, one right) fastening the rotational mode. Ideally I should remove the head from the column casting and scrape it in, but that is a big job – remove, scrape, fit and repeat…The head is HEAVY!

Next. move the DTO to the set East_West roll of the head, relative to the column.

East-West Roll

The two head-roll bolts were then loosened and the head tapped into vertical, bolts fastened, re-tested, etc.

The DTO was then moved back to the North_South position and nod re-checked. This since if either nod or roll are out, the DTI tip will not ride down the true axis of the test bar, but slip over the edge on the circle., so to say, with a false DTI reading. This was checked and redone a few times, till nod and roll, wrt the column, was less than a third of a DTI division or so over the 250mm test bar length. ( 1 div = 0.01mm)

For reference, the head was locked on the column, and the DTI set to midway on the test bar height, set in nod mode position. The quill was then fed down to its limit, with the DTI registering no discernable deviation.

The DTI was then fitted on the table, now to verify column perpendicularity to the table.

Image below shows test setup for nod – North_South tilt. This required a 0.004mm shim at each top bolt, between column base and Table base.

The same was done with the DTI set on the right of the test bar, for East_West.setting. Final DTI readings were less than 1/3 division.

That was good enough..

North South Column Tilt

Then the last was to set the DTI on the elbow in the collet chuck in the spindle and rotate the dti over the table to check if the reading was good – Table south, 0, table north, 0.002, table east, 0, table west 0.

To qualify, 0.003 is an estimate based on eyeing the needle between division – not easy!

Also, a movement of 0, is not actually 'zero/' but the smallest of needle tip 'wobble' discernable.

The test bar..

And its certificate..

Can someone explain the meaning of the terms on this certificate?

The diameter of 30 = 30.003, ie, 0.003 error, I understand, but the rest?

Now ready to start boring..!

Thanks again to all.

Joe

[Joseph Noci 1Participant @josephnoci1]

Posted by Jim C on 04/11/2020 15:13:02:

You talk about doing some accurate deep boring on your mill. I am interested how you do this on a mill that has a very small quill movement and a circular column. To date I have not had a job where I could not use the lathe to do the boring and would be a bit reluctant to unlock the head of the mill and use that to bore with. I’m worried that the head will move slightly on its gib strip ??

Interested in comments from FB2 or similar mill users.

Jim.

Jim, I have always tended to use the vertical feed for boring, not the quill feed. I have not had any problems – obviously, DOC must be conservative as the round column is not that rigid to start. However, MOST important is to ensure that the column sliding casting is really snug on the column. I release the gib totally, loosen the two set screws on the right side of the casting ( impinging on the two casting compression bolts on the left side), loosen the two compression bolts, and then begin snugging them up in turn, while downfeeding the head assy. At the point where the head begins to snatch, ie, downfeed is not smooth but grabs ( ensure both compression bolts are equally 'tight' at this point). Then tighten up the two right hand set screws – they push the compression bolts out, releasing compression a little. The head should now downfeed smoothly.

Then I do the same to the gib set screws. At this point boring is no problem! Run the head up and down a few times to ensure it does not grab anywhere in its travel.

As to why I am doing some deep, large diameter boring, I am busy with a DIY CNC lathe – a scratch build, not a conversion, and the boring is the headstock spindle bearing assembly- I will do a post on the Lathe, so won't contaminate this thread..

Joe

[Michael GilliganParticipant @michaelgilligan61133]

Joe,

I believe the column headings in the table mean

| Measure | Tolerance | Actual |

MichaelG.

[DiogenesIIParticipant @diogenesii]

..and

?Taper half-angle

Straightness

Parallelism

Diameter

..I think..

Nice, by the way..

Edited By DiogenesII on 05/11/2020 07:26:20

[Joseph Noci 1Participant @josephnoci1]

Posted by Michael Gilligan on 05/11/2020 06:40:50:

Joe,

I believe the column headings in the table mean

| Measure | Tolerance | Actual |

MichaelG.

Michael,

Yes, I understood the heading, but not what they were referring to …

Thank DiogenesII – Now I know!

What is the 'A' in 0.005/A – ( Angstroms..??..5nm..??) – That is one straight piece of steel…

Joe

[Kiwi BlokeParticipant @kiwibloke62605]

Joe, good to hear that you've localised the errors and taken steps to fix them – at least for the upcoming job. But you'll end up scraping the head swivel faces, won't you? Actually, I don't think it's as bad a job as you fear – measurements of lack of parallelism aren't too difficult on this fairly lightweight and easily-dismantled machine. (The head's not that heavy, and I'm considerably older than you!) You can remove the column, fit it to the head-carrying casting, place the casting's swivel-bearing face-down on a surface plate and measure between column and surface plate, and you can use your impressive test bar similarly to check parallelism of spindle to back face of the head. The bearing surface area is relatively small, as far as some machine scraping jobs go.

Just to spoil everything with a damper… Have you checked for lack of head rotation about the column, as the head is fed vertically? The key, and/or its housing in the column isn't perfectly straight on my FB-2. Who said accuracy was easy?

BTW, how do you get hold of things like your enviable test bar where you are? Stuff like that seems to be made from Unobtainium here in NZ…

Edited By Kiwi Bloke on 05/11/2020 08:48:47

[Joseph Noci 1Participant @josephnoci1]

Posted by Kiwi Bloke on 05/11/2020 08:45:24:

But you'll end up scraping the head swivel faces, won't you? Actually, I don't think it's as bad a job as you fear – measurements of lack of parallelism aren't too difficult on this fairly lightweight and easily-dismantled machine. (The head's not that heavy,) HAH!

Just to spoil everything with a damper… Have you checked for lack of head rotation about the column, as the head is fed vertically? The key, and/or its housing in the column isn't perfectly straight on my FB-2. Who said accuracy was easy?

BTW, how do you get hold of things like your enviable test bar where you are? Stuff like that seems to be made from Unobtainium here in NZ…

The head is more than heavy enough! Also, for fear of overdoing it, I would scrape too little, and work my way up to it – which means 3, 4, or more fit and test trials..This head will NEVER rotate again on the column, so for the medium to long term – the shim stays!

Regarding head rotation around the column – that would happen if the keyway in the column was not machined straight down the side, or was unevenly worn on one edge somehow. But my tests verified the lack of a problem by default – when doing the head roll test ( East_West) with the DTI on the column, if the head spiralled down the column, it would be impossible to get a zero reading on the DTI when moving the head up and down, just by adjusting the head East_West tilt or roll.

The test bar – abt 4 years ago I purchased an EMCO 14D lathe from EMCO in Austria, and as that was a huge amount of bother – on a ship for 3 months, road transport in Namibia from the harbour, etc…I though I would get ALL the accessories for the Lathe while about it – the spindle and tailstock test bars were part of it…( well , almost all accessories ..money prevented all…no taper turning attachment, and a few others..)

Joe

Edited By Joseph Noci 1 on 05/11/2020 11:02:52

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Joseph Noci 1 on 05/11/2020 07:35:41:

Posted by Michael Gilligan on 05/11/2020 06:40:50:

Joe,

I believe the column headings in the table mean

| Measure | Tolerance | Actual |

MichaelG.

Michael,

Yes, I understood the heading, but not what they were referring to …

Thank DiogenesII – Now I know!

What is the 'A' in 0.005/A – ( Angstroms..??..5nm..??) – That is one straight piece of steel…

Joe

.

Sorry, Joe … I didn’t realise that you were querying the standard symbols

**LINK**

GD&T Symbols

MichaelG.

[Joseph Noci 1Participant @josephnoci1]

Michael, thanks for that link – I 'dabble' in this field and was not aware of that!

Joe

[Michael GilliganParticipant @michaelgilligan61133]

You do some mighty impressive ‘dabbling’ Joe !

MichaelG.

[Graham MeekParticipant @grahammeek88282]

Hi Joe,

Glad to see you have the FB2 sorted.

Regards

Gray,

[Joseph Noci 1Participant @josephnoci1]

Graham,

Yes, Thank You. Your suggestion of the use of the test bar was a huge help.

Appreciated!

regards

Joe

[Graham MeekParticipant @grahammeek88282]

Something I have not mentioned so far is the FB2 Slotting attachment. Originally designed to ease the slotting operation on the Rack location in my Centring Attachment.

This was sold via Neil Hemingway and while the first batch of 10 was easy enough to do on the lathe. The subsequent larger batches required something to ease the stress on my right arm.

Of course the attachment had other uses than for what is was intended, and once set up it could be used for other things.

These included the internal keyway for the Myford Handwheel dial, (shown in the opening photograph), which Neil was selling quicker than I could make them, (no far Eastern DRO's back then). Then when the supply of Racks for the Centring attachment dried up these too could be made on the FB2.

The adjustment teeth in the Push-Pull Scraper posted just before Christmas were also cut using the Slotting head while it was still set on the Rotary Table. This was done after profiling the Head of the scraper with and endmill.

Here are the component parts, the unit has one stroke, making this adjustable would have made the unit protrude further from the face of the Milling head which would have put more strain on the Quill housing. More than I was prepared to accept, for what was considered a luxury.

Regards

Gray,

Edited By Graham Meek on 06/01/2021 11:43:19

Edited By Graham Meek on 06/01/2021 11:44:11

[Graham MeekParticipant @grahammeek88282]

A while back I was contacting various friends to see if they had the number of the ball bearings used in the FB2 main drive Motor. The reason being I would rather have new bearings to hand prior to dismantling, than have to wait for new ones to arrive. Joe in SA even offered to take one of his machines apart to find out, but I could not put him to all that trouble.

Eventually through prolonged enquiries with the manufacturers of the motor, ATB, I have found out the number of the bearings they use, which is 6201 2RU.

There are other motors used, but to date I have not been able to find these bearing numbers.

When I dismantled the motor I found that the bearings were just about at the end of their life. The grease had all worked out of the bearing through the non-contact seal. I am not surprised at this, as the temperature in my workshop has been in the low 30C in the past couple of years. With the FB2 motor sitting just below the insulated roof, but next to the skylight.

I hope these notes will help anyone else contemplating a motor strip down.

Regards

Gray,

Edited By Graham Meek on 17/04/2021 11:00:15

[Joseph Noci 1Participant @josephnoci1]

Thanks for that info Graham. Perhaps timely as my 'main' FB2 motor has developed a rumbling sound – I removed the motor from the gearbox and it is the business end bearing that sounds done…Trust my motor bearing numbers will be the same!

Thanks Graham.

Joe

 

Edit – syntax

Edited By Joseph Noci 1 on 17/04/2021 11:09:57

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Graham Meek on 17/04/2021 10:58:09:

[…]

Eventually through prolonged enquiries with the manufacturers of the motor, ATB, I have found out the number of the bearings they use, which is 6201 2RU.

[…]

I hope these notes will help anyone else contemplating a motor strip down.

.

This might be useful as an addition to the data: **LINK**

https://koyo.jtekt.co.jp/en/products/detail/?pno=6201%202RU

MichaelG.

[Tim ChizoParticipant @timchizo58850]

Hello Graham,

I'm new to the forum so please forgive me if I make any mistakes. I just came upon a FB-2 Mill and I have taken the motor apart. The machine is in quite bad shape missing parts but I am on the road to recovery. The bearings you are asking about, here in the U.S. are common sealed bearings ranging from 3 to 15 dollars.

On another not one of the parts I'm missing is part # E3A 000 150 Adaptor, Does anyone have one or drawings in order to make one?

Thanks,

Chiz

[Graham MeekParticipant @grahammeek88282]

Hello Chiz,

Sorry for the delay in getting back to you and welcome to the Forum.

You are going to have your work cut-out on restoring the FB2, but it will be worth the effort.

I am due to take another FB2 apart next week. I will make a drawing of the part and post it on here sometime next week. From memory the part has two Left Hand threads and quite a large hexagon for such a small thread.

Regards

Gray,

[Graham MeekParticipant @grahammeek88282]

Hello Chiz,

Please find above the details you need, I have managed to get the drawing done a bit earlier than I expected.

Regards

Gray,

[Graham MeekParticipant @grahammeek88282]

Hi Greensands,

Please find attached the drawing of the FB2 Dividing plate as promised.

Regards

Gray,

(I have provided PDF's on both the above drawings, and hopefully they will be loaded later.)

 

Edited By Graham Meek on 13/06/2021 13:07:10

[Neil WyattModerator @neilwyatt]

Graham has sent me two documents to upload, they are:

FB2_Rotary_Table_Dividing_Plates.pdf

FB2_Motor_Adaptor_Boltl.pdf

Thanks Graham.

Neil

[Author]

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