Very stiff Emco FB2 quill

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Very stiff Emco FB2 quill

This topic has 26 replies, 9 voices, and was last updated 23 October 2022 at 12:01 by Graham Meek.

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24 August 2020 at 19:12 #492365
Chris Long 1
Participant
@chrislong1
Hi, I wonder if anyone can help me with a strange issue with my Emco milling head. Its actually mounted on a Maximat 10P, but the heads at the same – mine is the six speed one. The quill feed (not the main mill down feed) is very stiff – requiring almost both hands on the handle to move it, needless to say the return spring is not doing anything. By way of full disclosure and for maximum embarrassment I need to admit how it got to this situation – I left the my ER collet on it MT2 taper in place for many months – I hadn't needed to remove it. Needless to say it had jammed and after trying other approaches (I know what I should do….) I ended up with the hammer option. This was "ok" until I lowered the quill to its full extension and tried thumping it again. This caused the problem and also didn't free the taper, so I've disassembled the head which is remarkably easy – I'll write another post on how if anyone is interested. So I had it all apart and I can now say that it is NOT:

1) The quill lock – this is backed right off

2) The quill alignment screw on the left, which runs in a keyway

3) the drive splines – the tightness occurs before these are engaged

So I've gone over the body of the quill looking and feeling for any raised areas – like at the start of the rack perhaps caused by an idiot with a hammer. I've re-inserted and looked for scoring, I've applied engineers blue looked for obvious tight spots. I've used a light emery on any possible issue spots, but the thing is still tight.

Anyone got any ideas?
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24 August 2020 at 19:12 #14009
Chris Long 1
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@chrislong1
24 August 2020 at 21:37 #492395
Trevor Crossman 1
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@trevorcrossman1
Hi Chris,

Well I cannot offer you a solution but if it's any consolation at all, I too have an FB2 mill and the quill has become incredibly stiff for the first 15mm or so of stroke, after which it is quite free and will retract by the return spring. There's no scoring, rusting, dents or dings nor have I thumped it heavily to remove a taper shaft. In fact I got so fed up with it sticking that I made up a 16mm thick split collar that is clamped to the quill, okay I loose a bit of stroke but rarely use the quill feed anyway. This is a second (third? perhaps) hand machine so I have no idea how it had been treated before I bought it, and was slightly sticky then but has got worse over the past year.

If you discover the cause and an effective solution I'd like you to share!!

Trevor
25 August 2020 at 12:25 #492495
Chris Long 1
Participant
@chrislong1
Hi Trevor, Thanks for your reply, mine was perfectly free over its whole range before I intervened. That said, like you I very rarely use this feature, so its not the end of the world. I'm waiting for a replacement oil ring, so have got a day or two to ponder how two large lumps of metal could go from free fit to interference fit.

Chris
4 October 2020 at 15:03 #499508
Henk Bonestroo 1
Participant
@henkbonestroo1
Hello Chris,

I disassembled the quill yesterday because I have the same problem as you have. Somebody suggested that it could be the o-ring getting sticky but that was not the case. I can't imagine the inside bore being scored and I can't see any scoring on the outside of the quill. Without the o-ring the quill enters quite easy the first centimeters and then locks up. Should I try lapping compound I wonder? Not anxious however to try anything that can make things worse.

Did you solve this problem Chris?
4 October 2020 at 16:46 #499524
Dave Halford
Participant
@davehalford22513
Is there perhaps a brass 'pill' under the quill lock?
4 October 2020 at 20:40 #499561
Henk Bonestroo 1
Participant
@henkbonestroo1
No not that I can see. Carefully inspected the inside for things that could obstruct the quill and removed the quill lock mechanism. But I'm a beginner in milling so I'm open for all suggestions.
4 October 2020 at 21:27 #499568
Oily Rag
Participant
@oilyrag
Hi Chris – have you checked the earlier posts on FB2 mills? Chris Meek has written some really useful information and seems to know these items inside out. No doubt Chris will be along to share his knowledge sooner or later.

Martin
4 October 2020 at 22:55 #499580
Bazyle
Participant
@bazyle
I suggest you disconnect the spring and then see if it is the quill itself that is stiff or the mechanisn that moves it. If you took out the pinion part of the operating mechanism it might be that removing and reinserting so a different part of the rack/pinion engage. The pinion might be eccentric wrt its bearings.
5 October 2020 at 08:37 #499604
Joseph Noci 1
Participant
@josephnoci1
Hi Chris.

Do you have the spares manual for the machine? It shows the numbered breakdown/exploded view of the head, quill and gearbox.

I have three of these machines so know them reasonably well, but to try help it would be easier to refer to the numbered elements in the exploded view.

When you say you have stripped the head down – to what extent? Have you removed the Drive pinion, item-6?

You have removed the quill (41) from the head. Does sliding drive gear ( 12) slide freely along the quill spline?

In the exploded view, page 10 in the manual, remove all the elements in the vertical line above the quill ( 41), as well as all items associated with the spline drive pinion, item-6 on page 8 , and the quill alignment screw (15 – page 8). Also ensure the quill locking screw ( 43, page-8) is loose.

Then can you insert the quill into the head form either top or bottom, or both, and see if the quill sticks and where it may stick? You may already have done this..

If loose from the top till it almost exits the bottom, then I suspect the split clamp at the bottom is bent or twisted – although prudent use of marking blue should have shown this.

Please expand a little on your statement –

I've applied engineers blue looked for obvious tight spots. I've used a light emery on any possible issue spots, but the thing is still tight.

This makes no sense at face value – if you coated the entire quill outer (needle bearing case) shell with blue, and it shows no mark-off on the inside of the cast iron shell in the head, it cannot be stiff…

Can you post some photos of what you have done?

When you say the MT is seized and you resorted to the hammer, do you not have the draw bar and top nut release mechanism? I presume that when you did the hammering you did not support the quill exit-taper with a forked support? That is most unfortunate, as in that quill the needle bearings, which are a very specific pre-load fit, take the full brunt of the knock, end on, and that invariably leaves micro 'dents' in the bearing surfaces at the needle ends. The end bearing in the business end of the quill also suffers the same fate..

There is a section of the quill outer, around 1/3 down from the top, that is thinner in wall thickness than the rest of the tube. The bearing above this impinges on an inner flange section above this thin wall, and if the flange is bent downwards, the outer wall cab bulge, or bulge in an oval fashion. That will cause stiffness for sure! However, marking blue should show this right-off. You can also Mic the outer diameter all over, checking for better than 0.02mm…

When this 'ovalling' has occurred, it is generally accompanied by a stiff spindle in the quill as well – thats the end of the quill, if so!

If you do not have the manuals, I can send you the PDF if you PM me you info, or I can post images here, but the resolution will suffer as there images I have are BMP and I have to convert to JPG for the posting. I also have PDF..

Regards

Joe

Edited By Joseph Noci 1 on 05/10/2020 08:43:16
5 October 2020 at 11:01 #499631
Chris Long 1
Participant
@chrislong1
Hi, thanks everyone for your replies. Its been a wet weekend so by chance I've taken the mill apart again, actually doing almost all the things that Joe Noci has suggested in his post, even though I hadn't seen the post! This was motivated by checking the runout on the spindle and having found it to be more than +/- 0.02mm I was thinking I had indeed damaged the bearings. I've taken it apart more thoroughly, this time removing the main drive gear (Part 12 in the manual, called "sliding gear" – @Joe, thanks yes I have managed to find a manual online, however the numbering is plainly different, perhaps I could get a copy of yours…). This was prompted by the thought that the stiff quill might be caused by the top static bearings tat support this gear being misalligned due to my inappropriate earlier actions.

(Note: there are five bearings in total. The quill/spindle has three – needle rollers at the botton and two ball races at the top. Then there are two more ball races holding the slide gear in place (which itself doesn't slide).

This has revealed several things:

1) There is ample clearance on the splines – they aren't damaged, nor do they cause any resistance, therefore the chance of a misalignment .

2) The run-out on the splindle is unmeasurable when the quill is re-inserted without the drive gear assembly – i.e. the needle simply doesn't move, so better than +/ 0.002mm. This looks like good news, I assume it means these bearings have survived with little or no damage

3) The sliding gear bearings seem to be OK – need to do some more checking on this

4) The quill is still stiff – so having removed the quill locking mechanism, (I can confirm that it is nothing to do with that), This reveals that the quill locking body is permanently gripping the quill – it is a split collar type locking mechanism – either it is permanently bent inwards (i.e. in the direction the locking handle applies), or in a downward direction due to force from above. I've used a spreader to investigate the first option and this has made the bottom of the quill movement much easier. However I'm concerned about the second option – and this chimes with what you mentioned Joe.

5) I've inserted the quill from the top and the bottom, both the correct way and "upside down" and concluded that something is tapered. Either the quill tapers (narrow at the top), or the bore tapers. Generalising I'd say it goes in easily until the bottom of the quill meets the bottom of the body (regardless of direction. This again points to the split collar being bent slightly.

So I'm currently pondering what this means – the quill is now a little looser, having worked the locking arms apart slightly. The bearings on the face of it seem ok, its just when it is all assembled I get that run-out. It might be that the top bearings if put back in after the quill might assume a more cooperative position… I'm very reluctant to go anywhere near lapping compounds – these components used to fit together OK, so the question is what has changed? @Joe I will investigate your comment about the bugle in the quill. My attempts with the engineers blue indicated that there were no specific high points around the quill – but I was looking for vertical lines – where some single point (like the splines for the quill handle) had been damaged and therefore rubbing. Your idea would cause tightness all around and I thinking all I would see is blue everywhere – which is what I did see, but doesn't differeniate between normal and tight…

I'll update you on progress this week.

Chris
5 October 2020 at 12:20 #499647
Henk Bonestroo 1
Participant
@henkbonestroo1
Hi Chris (Long1),

My name is Henk and I live in the Netherlands and new on this forum. Since I encountered the same problem as Chris. I'll post some photos of the spindle and quill. Checked for roundness of the quill and it is within 0,01 mm except for the top of the keyway. There I measure a few hundreds more thickness. Could it be that if someone (I got it second hand) tried to force the quill beyond the 40 mm down movement with extreme force and caused a high point at the end of the keyway?
5 October 2020 at 16:22 #499707
Dave Halford
Participant
@davehalford22513
Definitely looks bruised and like it's been rubbing at both ends, perhaps someone hammered the quill down to set the taper.
6 October 2020 at 11:15 #499849
Graham Meek
Participant
@grahammeek88282
Hi Chris,

I have just been reading through your opening post for the first time today, As soon as I read you lowered the Quill in your attempt to extract the taper, I knew what had happened.

There is bound to be damage at the top of the Quill Guide slot as Henk shows above, but may be not as bad as that shown. You may have also damaged the locating bolt end where it fits into this slot. It may even be bent, and so may be rubbing on the bottom of the guide slot as there is not a lot of clearance here.

I suspect also that you will have damaged the Ball races in the Quill itself due to the hammering. Beware the circular nut in the centre of the quill is a LH thread, should you decide to take this apart. Unfortunately the ball races are not standard issue. They are specially made for Emco, in that they have to be assembled with the faces marked abutting. This takes out any end play in the races. Replacing these with standard races will probably lead to some play in the spindle vertically.

Hope these notes help,

Regards

Gray,
6 October 2020 at 20:32 #499967
Chris Long 1
Participant
@chrislong1
Hi Gray

Thanks for your message, I suspected that I might have done this before my very first post, but at that point, on inspection there was no visible damage to the end of the slot. I had gently ran I file over the edge of the top of the slot in case, before embarking upon the engineers blue session… (BTW for others the slot is a keyway cut in the quill. There is a bolt on the left hand side at the base of the milling head, which engages with the keyway and keeps the quill from rotating. If you don't remove the bolt and hit the top of the quill it could burr the keyway, as in Henk's pictures, if you do remove it and hit the quill you will burr the quill splines instead… DONT HIT IT)

Anyway, to double check I'd also got my surface table out and started looking for bulges, etc, based on Joe's suggestion. I couldn't find any. I got a light behind the table and quill and could see if there was anything out of true as I rolled it along the table. I could only see light when the splines or keyway were lowest, which was what I expected. The keyway has actually removed part of the circumference of the quill so you can see light at that point. That was yesterday. After your post I went back and had another l look, and discovered that on close inspection, when the keyway is lowest, the light stops momentarily at the top end of the slot! There is actually a high spot right where you suggested. So back on the bench I've very carefully removed this with a small modeling file and finest emery, taking about an hour to remove just the smallest amount each time. Result is that the quill now goes back where it should without much resistance. For others in this situation I think it is worth pointing out that this damage (a) isn't visible to the naked eye, (b) you can't feel it (it isn't a burr) and is (c) quite difficult to spot even with the surface plate and light. (d) Measuring with a height guage and using calipers both failed to pick it up.

Anyway, I'll update on the reassembly results, but thanks for your suggestion. I'm hoping the bearings haven't gone…

Chris
6 October 2020 at 21:00 #499975
Dave Halford
Participant
@davehalford22513
Shows you how tight the quill tolerance is.
7 October 2020 at 12:36 #500059
Graham Meek
Participant
@grahammeek88282
The actual EMCO Quill drawing states a tolerance of g5 on the 52 mm diameter. This in terms of a measurement is -0.01 / -0.023 mm, or minus 4 to 9 tenths of a Thou.

Emco in their infinite wisdom specify a chamfer of 0.4 x 45 degrees at each end of the slot to try and mitigate burrs at this point from affecting the sliding fit.

Regards

Gray,
7 October 2020 at 20:30 #500121
Chris Long 1
Participant
@chrislong1
OK, its back together and with the spring the quill returns to the top on it own – quite smartly as before. Even better it is still able to mill (Aluminum) at least.

Can anyone confirm the oil specification – after some research I bought some ISO 46 oil (specifically Kerax ISO 46 HVI Hydraulic Oil High Viscosity Index Fluid DIN 51524). However it seems thinner than what was in there before and as a result I'd say the head is very slightly noisier. Previously I'd used SAE 40 I think…

Thanks for you comments and assistance getting things back working!

Chris
7 October 2020 at 22:12 #500138
Henk Bonestroo 1
Participant
@henkbonestroo1
Hi Chris,

According to the Emco service paper: Castrol Hyspin Aws 46 or equivqlent, so I think you're good.

Henk
8 October 2020 at 11:00 #500175
Graham Meek
Participant
@grahammeek88282
The recommendation in my 1996 manual says to use the same oil as the slideway, ISO VG 68. As the machine came filled with Castro Hyspin ISO 46 Hydraulic oil, and I have a good supply of this, I have continued to use this. In one machine I did try a multigrade synthetic transmission oil. The only down side to this was the smell which would come out of my vent valve during use. I detected no change of noise level using this oil.

I was not keen on using a straight oil, like the slideway oil, because this can cause foaming in the gearbox. Most hydraulic oils have foaming inhibitors, and some are better than others. The foaming will make the oil circulation pump less effective and slow down the circulation of the oil to the upper bearings.

Overfilling the gearbox can make it noisier, due to the pumping action of the gears, (more oil means more gears rotating in the sump due to the increased oil level). Emco recommend the oil level to be halfway up the sight gauge.

Glad to hear your spindle was not damaged,

Regards

Gray,

Edited By Graham Meek on 08/10/2020 11:01:56
9 October 2020 at 09:41 #500297
Graham Meek
Participant
@grahammeek88282
I also intended to post this yesterday but was called away.

One other source of noise and possible damage to the gears, is the setting of the 3 position Speed Selector. If this is initially set in the lowest position, (I), then the gears in this range can be meshing by only 1/2 a tooth width. It is better to set the selector in the fully up position, (III), and then check the engagement at the lowest setting.

Regards

Gray,
19 October 2022 at 22:30 #617920
Bud Hennessy
Participant
@budhennessy58562
Hi all – I am the happy new owner of a EMCO Maximat Super 11 with the FB2 milling attachment. On getting the machine home I noticed I could not get the ESX-25 collet holder out of the FB2 quill. I asked the previous owner what he knew about it and he was oblivious. Together we looked at it and concluded it was held in with a long bolt and washer, but not the factory bolt (item 27 in the manual) and the nut (item 22) is not with the machine. We eventually came to the (apparently wrong) conclusion that loosening the bolt and tapping it to release the collet holder was the ticket… While that approach proved successful it took quite a bit more than a little tap though, a few pretty hard whacks with a brass hammer eventually did the trick. However, now I notice that the quill no longer runs smoothly up and down and is binding pretty substantially at the top of its stroke and is pretty much bound up over its full travel except for maybe the last 3/4 inch at the bottom where the return spring actually works, sort of… Honestly it's very possible that the quill did not move smoothly even before we whacked it with the hammer; it wasn't something I checked or tested before moving the machine home.

From reading through this thread over and over again, it seems like I may have damaged the quill bearings and possible that the quill assembly should just be replaced. And I've located a replacement quill.

So my question is; what is the quill removal procedure? I presume I need to drain the oil and pull the shaft pinion assembly (item 6 in the drawing) , but then what? Does the entire top end of the head need to be removed? Or might the quill assembly just drop out the bottom of the FB2 head?

Thanks all – Bud
20 October 2022 at 11:34 #617958
Graham Meek
Participant
@grahammeek88282
Hi Bud,

After removing the Quill feed pinion and the clamp if fitted that holds the cable for the motor.

You will first of all need to remove the motor. Beware this has an extension piece on the end of the motor shaft which is the oil pump for the head. You will need to raise the head about 150 mm to clear this before any sideways movement.

There are 6 x M6 capscrews retaining the top cover, but before removing the cover wind a few wraps of insulation tape or similar around the thread on the end of the spindle to protect the oil seal in the cover. The cover is dowel located around the oil pump bore so it may need a Light tap with a soft mallet on the rear overhang of the cover.

The circlip at the top of the spindle needs to come off next, the tape will need to come off now. This is under pressure from the spring so watch out. Remove the spring and seat along with the Quill alignment bolt. At this point the Quill is free to drop so make sure you have had the Quill lock on during this time.

Release the lock and the Quill should drop out or with a bit of applied pressure.

Assembly is the reverse of the removal process, but be sure to fit a New O-Ring to the Quill.

I hope this helps,

Regards

Gray,
20 October 2022 at 18:14 #618022
Bud Hennessy
Participant
@budhennessy58562
Hello Gray!

Thank you for the detailed reply. I think I understand the process and cautions.

On a related note, I replaced the FB2 oil and oil sight glass the other day since it was black. After replacing the oil it initially looked cleaner, but with some running has turned largely black again. I've seen some comments wherein people have put a molybdenum disulfide additive in the oil and suspect this may be why the oil has gone black so quickly. Is adding moly really necessary or even recommended? Or is it something to be avoided?

Thanks again,

Bud
20 October 2022 at 21:32 #618049
Graham Meek
Participant
@grahammeek88282
Hi Bud,

It may well be that Moly was added in an attempt to quieten the gearbox. Having had 3 x FB 2's over about 40+ years I have never needed any additive. The last machine I had up until June of this year had been running for many years on Castrol Syntrax. This being a fully synthetic oil does not need to be changed and is not going to degrade the O-ring seals. I used Syntrax after seeking advice from Castrol Technical staff.

I suspect you will need to do many oil changes to get the Moly out of your machine. It was not something that Emco recommended adding.

Provided you do not remove the side covers you can remove the Quill without draining the oil, provided the head is in the vertical of course.

Regards

Gray,
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