Member postings for Graham Meek

I regret to say the point I was trying to make is that we are totally ill prepared.

The laying of high voltage cables beneath London was I was told because the Grid cannot cope.

The installation of the heat pump on the program was costing £18,000.00 pounds according to the owner. At 71 years of age I am not going to lay out £18,000.00 just to get perhaps £5,000.00 from the Government.

As regards the efficiency again this is what was quoted on prime time TV by the BBC. It is of no consequence to me as I shall not be fitting one. (There is no room in my house for the rather large storage tank, for one thing).

Getting rid of coal before there was something viable to replace it is madness in my book. There are Carbon capture plants already in use around the world.

Regards

Gray,

I don't know if any of the members saw the two programs on the BBC recently about the change to Electric cars and Heat Pumps.

To iterate some of the posts here we are totally ill prepared.

An estimate of the current fitting of Heat pumps means it will take 400 years to complete. A system that produces three times the heat for the energy put in (????) and uses electricity which is three times as expensive as gas. I don't think I will be fitting one anytime soon. The latest Nuclear plant is still being held up in the planning stages and has been for 10 years. The national grid cannot cope with the off shore electricity produced, so the companies are paid to turn the generators off.

A more efficient means of carbon capture from the burning of coal would be my way forward, and I don't mean pumping the stuff into disused oil wells. Carbon is one of the building blocks of life it's removal from the emissions means it could be used for other things. It just requires a bit of thinking outside the box.

Unfortunately big money runs the current thinking which is all electric.

Regards

Gray,

Hi Roger,

If you have not got your part sorted yet I can repair this on my Compact 5, I am in Cinderford.

Regards

Gray,

Hello Neil,

While I have started writing this up, it has been delayed for various reasons. Downsizing the workshop being the main reason. Although I do use this a lot when I am in the workshop. Finding time for the workshop and writing, is proving difficult at the moment. Maybe as the darker nights start to pull-in I can find some time.

Regards

Gray,

The reason why the Carriage gets tighter as it moves towards the end of the Bed is due to the geometry of the machine.

The Leadscrew centre-line is fixed in relationship to the Profile of the Slideways on the actual Bed.

Excessive wear on the Carriage Slideway Profile, now means the Leadscrew tapped hole will be sitting lower than was originally intended. This is not so bad when the Carriage is nearer the Headstock as there is some play in the system. As the Carriage nears the fixed Leadscrew bearing this will cause binding due to the misalignment of the two items. Any attempt to reduce backlash in the system will only exacerbate the binding.

This was, apart from wear in the original thread, one of the reasons I did the above salvage scheme on my Unimat restoration. As wear in the current Carriage set-up takes place a new Phos Bronze Leadscrew Nut can be made with a slightly offset tapped hole to cater for this misalignment.

The fitting of the new Nut brought the backlash back to 0.05 mm which is what I would expect. Although this is the original leadscrew of unknown age, there is no change in the above figure through-out the length of travel.

Regards

Gray,

I have added an additional view for those who want to make this conversion. It relates to the amount of material that needs to be removed from each side of the Vee. Please note this only applies to a 2 mm wide slot. If the slot is less or more than this then some trig will work out the different dimension.

Regards

Gray,

Here are the drawings of the modification. As I said earlier this is not something for the faint hearted. It is easy to achieve provided the project is approached methodically. To make the New base I would recommend using a jig which is machined in situ in the dividing head, with tailstock support. A tenon machined on the jig will automatically orientate the base to ensure alignment. The base can be held on the jig using the two 6 mm diameter access holes for the grubscrew which locks the tailstock feedscrew bearing and the Dog point Barrel alignment grubscrew. M5 tapped holes will be more than adequate.

Rotating the dividing head will ensure a perfect 90 degrees for the Vee. Provided the bottom of the Endmill or slot drill is used. Once the Vee is established the 10.50 mm dimension can be established. This also ensures all surfaces run parallel to one another.

It would pay to leave the base oversize on thickness, say about 0.1 mm to allow for some fine tuning once all the parts are made. It is always better to have material to come off than having to put some back on or even starting again.

To machine the tailstock a set up as used earlier in the post using two Vee blocks and a mandrel will ensure the alignment of the tailstock barrel bore and the Tenon.

Regards

Gray,

As promised I have made a start on the Tailstock Base Salvage scheme, as used on my own C5.

Unfortunately during uploading to this site the drawing has turned through 90 degrees.

The scheme incorporates a means of moving the tailstock laterally across the bedways. This involves one M5 grubscrew being in contact with the inside wall of the tailstock casting nearest the M6 Clamping screw. While an M6 grubscrew impinges on the rear inside wall of the casting.

Access to this adjustment is via a hole which Emco kindly provide in the back of the casting. Unfortunately this hole is in two different places on the tailstocks that I have. The newer casting has the hole lower down as shown. To accommodate the casting with the hole higher up just requires making the head of the spigot taller.

This spigot also locates the clamping plate, (which needs to be modified with a 6 mm hole), and stops this plate from jamming when moving the tailstock. The addition of a spring around the M6 clamping screw between the plate and the the new tailstock base, further refines this set-up.

The M6 grubscrew is drilled though to allow a 2.5 mm A/F Allen key access to the M5 grubscrew. This moves the tailstock towards the operator while the M6 grubscrew moves the tailstock away form the operator.

Once the optimum setting is reached the two grubscrews lock the casting to the new base plate due to the opposing forces of the grubscrews. This however does not want to be overdone as there is a risk of breaking the rear tailstock casting wall.

I have yet to dimension the drawings which I hope to complete over this weekend.

Regards

Gray,

In the original set-up the needle roller cage is retained onto the coupling that fits inside the above gear by two C-Clips. These retain and locate the needle roller bearing on the coupling. Pressing a bush into the above gear means it would not be possible to fit the leading retaining C-Clip, or the parts cannot be assembled.

This type of needle bearing assembly allows for some degree of self alignment, endwise within the housing bore. It may need several trials to get any pressed-in bearing, in the correct endwise position.

A few words of caution.

If this bush should seize at speed then not only is the gearbox and transfer box going to suffer, but it could also lead to an accident. It may also mean invalidating the insurance on the vehicle, as fitting this bush would be modifying it.

Regards

Gray,

I for one do not think the phos bronze will hold up long when used with a needle roller bearing.

I did think from reading the original post that the phos bronze bearing was to run in the original needle roller race housing bore?

This is where a drawing or better still a photograph saves a lot of speculation.

Regards

Gray,

Not having a picture or a drawing to work from.

As I see it the worn section of the shaft is no good for a Needle roller to run on?

Is the worn section in the centre or on the end of the Shaft?

If this worn section is on the end of the shaft then it could be turned down and a Needle bearing Hardened Sleeve, (commercially available), be secured with Loctite. This will ensure this bearing is always repairable.

If it is in the centre of the shaft then this area can be repaired using a spray welding technique. This area will need to be ground back to size afterwards. Distortion can be a problem but usually if this is done correctly this is minimal.

Regards

Gray,

Did the builder seal the floor before applying the self leveling compound? A diluted coat of PVA usually does the trick.

I ask this question because you can get air coming up from the concrete if this is not done. It may well be that the hole in the compound goes directly to the concrete. I would try a small area with some dilute PVA and then try painting that area again. You have everything to gain and not much to lose.

Regards

Gray,

Edited By Graham Meek on 10/07/2023 16:24:10

Good luck with the replacement Quill assembly.

Regards

Gray,

The two bearings at the top are sort of standard ball races and could possibly be at fault. Have you checked to see if there is any end float on the spindle? If there is some play, then I would say this is where the fault is.

These bearings are retained by a Ring Nut on the FB2 which has a Left hand thread on the spindle. You will need a peg spanner.

I had replaced the bearings on one machine with Angular Contact Bearings, (back to back). These are a direct fit. The original Emco bearings were a matched pair of standard bearings which are specially selected by FAG. These have minimal clearance when loaded correctly. These bearings had two markings on and these markings had to be assembled with the two marked faces together.

Perhaps someone has had this machine apart and not re-installed the bearings correctly.

If you are taking the spindle apart then I would get two angular contacts in ready.

Regards

Gray,

An equivalent bearing made in Japan has one extra roller from the standard one fitted. I obtained one from Simply Bearings, (usual caveat).

Regards

Gray,

Before you go stripping it down.

Where is the clock mounted?

Is it actually attached to the Milling Head or on the Table?

If it is mounted on the Table then the thumb pressure is also moving the Head on the Column.

If the Clock or Indicator is mounted on the Milling Head then provided the Quill is locked. Any play recorded is actually in the bearings.

Also keep in mind that these Needle Roller bearings have a little play in them, 0.005 to 0.01 mm. This will disappear as the bearing becomes dynamic, ie when the spindle is rotating and running on a film of oil.

This bearing fills with oil over time and becomes in essence an Hydraulic pump and the oil is in-compressible.

I have used FB2's for over 40 years, the spindle was never an issue once you get to know the machine.

Regards

Gray,

Your post came in while I was typing,

Edited By Graham Meek on 08/07/2023 11:01:15

One Tip I forgot to add with regards to the U3 Cross-slide feedscrew. I have modified the slotted M4 countersunk screw. Using a Ball Nosed slot drill as close to my grease gun nozzle as I could find. A depression is made in the head of the countersunk screw to just below the depth of the screwdriver slot. A small hole about 1 to 1.2 mm is then drilled through the length of the screw.

Grease can now be applied to the feedscrew in the centre of the feedscrew nut. The action of which forces any debris from the nut as the new charge of grease is applied.

I have not found this weakens the screw in the course of usage.

Regards

Gray,

Hi Kiwi Bloke,

You have redeemed yourself, the misunderstanding was not helped by me not being more specific and mentioning the feedscrew nuts in my comment.

The comment about gorillas over-tightening the bearing end-float is another good point. I have replaced more of these bearings for friends who have purchased secondhand machines than any other bearing on the FB2. Once set at the factory these will need very little attention. It could be many years before these ever need adjustment and this will depend on the amount of use the machines get per day.

Regards

Gray

Edited By Graham Meek on 03/07/2023 10:37:03

Hi Kiwi Bloke,

Some very valid points as regards stick slip and free rotation. It is a misconception that zero backlash is the best. If there is no play then there is no room for the lubrication film and this leads to accelerated wear. This wear then leads to backlash and the cycle continues. Whereas a regularly lubricated bearing will last for years without any adjustment.

On the Emco FB2 the instructions for setting the feedscrew backlash at the factory. This was set at 0.05 to 0.1 mm.

Regards

Gray,

Just a little point in passing as regards the cross-slide feedscrew nut on the U3. Backlash can be greatly reduced in this nut simply by using the taper of a screw driver blade to rotate the nut slightly before locking it up with the countersunk screw. I have found the blade is best inserted on the tailstock side of the cross-slide. With the adjustment being carried out on the least used portion of the thread.

Although the backlash has been reduced, because the nut has been rotated slightly there is always a reservoir of oil on the side of the nut not in full contact with the thread. Simple but effective.

Regards

Gray,