Here is a list of all the postings Ian P has made in our forums. Click on a thread name to jump to the thread.
|Thread: Best way to improve fit of main spindle quill in casting (long)|
I had a quote recently from a UK spindle refurbishing company to build up and grind the bearings seats of the bent spindle, it is totally uneconomic!
To refurbish two journals was over £300. Grinding the taper (presumably the MT2 bore) was £160
As far as I can measure the quill OD is not worn, it would be nice if a 48.00mm ID sleeve existed but I doubt I will be that fortunate to find one.
Ian, another Elan (Lotus) man
Thats why I made the new spindle.
One other point, I think making a new quill body is going to be harder than modifying the hewad casting, apart from having to get the two bearing seats at opposite ends of a tube in perfect alignment, there is the problem of cutting the rack for the pinion.
Thanks for all the comments and advice so far.
My original posting did not give a lot of detail but I can add some more info that will explain my predicament.
When I used the machine after I first got it I was not happy with the surface finish (even with a single point fly cutter) which I put down to the bearings. Its a long story but I have now made a new spindle and rebuilt the quill with taper roller races and with the quill tightly clamped the finish quality and accuracy is really good. Unfortunately the action of tightening the clamp puts disturbs the alignment of the spindle with reference to the table. (I trammed the mill as near perfect as possible but may not have had the quill clamped, or in the same position.) I do not know for sure, but I think that in the clamped position the spindle is not parallel to the Z axis so to get the spindle correct means the shims will have to slightly tilt the column which will compromise other aspects of the alignment.
I could re-tram with the quill clamped but not being able to use the quill as a quill is going to limit the usage of the machine slightly.
The bore of the casting is slightly bell-mouthed, however, looking into the bore I can see that part of the bore that moves under the influence of the clamp bolt looks to be unworn, in other words, does not make contact with the quill until the clamp it tightened. With the bolt loose the lontitudinal sawcut is perfectly parallel so I assume that the casting has not distorted or 'opened' up.
Being made by Emco (in the 1960s) the engineering is of a high standard and as I mentioned earlier the table, ways, leadscrews etc are all in almost unworn condition. As I am getting to know the machine better I realise that at some time in its previous life thare have been some 'issues' with the spindle (it was bent!) so finding this problem with the quill does not surprise me, it just adds to the condition-anomoly mystery.
The head casting is a cast iron cube shape, machined on all faces, I think, and I could mount it on my Boxford cross slide and make a boring bar. I have never line bored anything before, but until last week I've never made a new spindle from scratch and toolpost ground the various tapers and bearing surfaces so I am willing to have a go at boring!
If I make a sleeve after the boring operation than the exact bored ID is not critical but I imagine that the sleeve wall would only be 1.5 to 2mm thick so making that wont be so easy. I looked online to see if any engine cylinder liners might be available in the right size but cannot find anything with a 48mm bore.
I'd better stop as this is already getting a bit long.
I have an Emco milling machine that is in really good unworn condition apart from the fit of the quill in the head casting. I am considering some sort of bush or sleeve but thought I would see if anyone could suggest a better method.
The quill is 48mm OD, about 100mm long and has a travel of 40mm. The cast iron head has a sawcut and clamp bolt but inexplicably (to me) is quite badly worn. I can easily put a 0.0025" feeler between the quill and the bore and it will slide in quite a long way. Tightening the clamp bolt obviously reduces the clearance but to clamp it firmly require more force on the bolt than feel right.
The OD of the quill looks unworn so I was thinking of boring the casting to take a sleeve of some sort. I could bore the casting in the lathe but making a sleeve with a 48mm bore and having only a relatively thin wall might not be too easy and then there is the problem of pressing it in place.
Another thought I had was reduce the ID of the casting by tinning it with soft solder, then boring it to the correct diameter. It sounds a bit crude but its not much different than white metal bearings, or is it? If I did this I would polish the quill OD to minimise wear of the soft surface.
Thsnk in advance for any suggestions
|Thread: Making this site easier to user suggestion|
Its not the green tabs I was refering to. Its the tabs that are a now fundamental part of Internet Explorer.
The reason for my request (no its a 'suggestion' really) is that if I open the MEW home page and see several titles of topics that I want to read the obvious thing to do is click and read the first one (which might involve plodding through several pages to get to the most recent post). If I then want to read a post on another topic I have to use the back button several time to get back to the home page.
I circumvent the problem by right clicking all the topics (and other things of interest) and opening each topic in a new tab. In effect each tab is another instance of Internet Explorer. One I have done that I can read select the first tab and read the postings, whilst I am doing that all the other topics postings are being loaded in the bacckground so are instantly there to be read.
I suppose its would be best if the website software showed the postings in reverse date order (newest first) if that was possible.
I have just re-read your reply and see that you actually said 'It will be done' but now I'm slightly confused about your question about the green tabs.
Either way, Thanks
As a frequent reader and occasional poster to the MEW forum I would like to make a suggestion that would make the site more friendly.
In common with other browsers IE8 (which I use) has the ability to open new 'Tabs' by right clicking on any page link. On most websites any new tab that is opened shows a title in the tab which then makes it obvious what will be brought up when that tab is selected. The MEW website shows the same title text in every tab (sic "Model Engineer"), so whether it another forum topic or a different page of the site they all look the same.
It would be great if this facility could be added to this site next time any site maintenance is being done.
|Thread: New Drummond Project|
If you want a flat belt without a joint the best option is to use a 'Poly Vee' belt inside out.
OK you have to install the belt by taking the spindle out but the life of the belt is likely to be measured in decades so its not something you will be replacing very often.
Polyvee belts are vailable in a multitude of widths and lengths and do not stretch, (not likely to wear much either) and run very smoothly at high speeds, although that's probably not important on a Drummond but they are ideal for a toolpost grinder or high speed drilling machine.
With a crowned pulley, flanges to keep the belt in place will not be required.
|Thread: Magnetised tools|
Although it is not my own idea I recommend making a demagnetiser out of an old central heating water pump.
The most suitable type of pump has a thin stainless steel plate between the two halves of its construction. One part (the wet side) contains the inlet and outlet ports, and the impellor, whilst and the other half has the electrical bits. The impellor is driven by the magnetic field being transmitted through the SS shim.
Throw the wet half away, fix the SS plate securely to form the working surface, ft a suitable switch and cable (Dont forget the earth lead!) and you have a useful tool.
I discovered thet its best not to leave it on for too long as without 'seeing' the rotor the windingtend to get hot after 15 minutes.
|Thread: Blown X1 Mill speed control|
As far as I know and assuming that all the 'X1' mills are the same then the motor is a permanent magnet brushed motor.
I found the motor/controller/and whole drive mechanism in general a bit lacking and have ditched the whole lot and converted my X1 to belt drive with a brushless servo motor (because I had to find some use for it!). I also modified the existing spindle to create a 'quill' arrangement.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.