Schaublin lathe spindle bearings: Part 2 - front bearing fitting and adjustment

Рет қаралды 3,278

Жыл бұрын

Fitting and adjusting NN type K double row bearings with tapered inners requires care and attention to cleanliness. Schaublin's instructions are inadequate and don't give enough detail on exactly how to proceed. Having fitted many of these bearings over the last 30 years or so, I've learnt from early mistakes and developed an approach which will hopefully be helpful to someone doing it just the once.
Apologies for the poor video quality in places.

Пікірлер: 18

@TheElderlyBiker Жыл бұрын

Glad to see the bed being used at last! Hope all is well...

@fuzzfacelogic789 Жыл бұрын

Thanks David, very helpful, although I imagine it would be even more of an adventure with a backgeared headstock

@davidsamways Жыл бұрын

There's certainly more disassembly involved in a backgeared headstock, but with all the backgearing components, pulley etc. removed the process is identical. Reassembly once adjusted is fiddly with a backgeared headstock.

@casimiriwaszkiewicz8962 Жыл бұрын

David, many thanks. As always, great detailed info about the “how to”. Also nice to see a short bed (single leg) 102 too.

@johnmaksim6279 7 ай бұрын

Mr. Samways, Thank you. I am conceptually following this procedure and to know when something is ‘good’ is difficult without the perspective of someone like you. I have a few questions - -supporting the rear of the spindle: are you describing a shop made bushing to support the rear of the spindle during this process or using one or both of the opposing rear bearings? -is the ‘oil ring’ you mentioned while pushing in the bearing sleeve the actual sleeve itself or something that lives inside the housing behind the sleeve, Or is it a part of the assembly that we are gradually tightening and tapping in this process? -and just to clarify, using the extension piece which overall length gives you some leverage, you are pulling ‘opposite’ the clock, towards you, without rotating, for the sake of applying that movement on the clock to the formula? Again, for the time you’ve taken to do these videos I appreciate you and it makes a difference for my approach and I’m sure saved me $ or peace of mind. Best, John.

@johnmaksim6279 7 ай бұрын

Mr.Samways, disregard the middle question. I see piece that must go in before the new sleeve and it has oil travel features. I am becoming more familiar with each of these parts. Best, John.

@davidsamways 7 ай бұрын

Hello John, I have the rear bearings in place - in this case it's the old bearings prior to replacement (adjusted so that there is no radial or axial play). As I say in the video, Schaublin do not specify what loads or how to apply them to the spindle. As we are only chasing a very small deflection measured by the DTI it's not necessary to pull away from the clock - the spindle should return to the centre. If you do pull away from the DTI then you would expect to see more or less the same reading. Rotating the spindle shouldn't make any difference, if it does then it suggests a problem with the spindle or the fitting of the bearing.

@cnxunuo Жыл бұрын

Great video! I was wondering if there is a good way to remove the outer race without risk of scratching the headstock bore?

@davidsamways Жыл бұрын

Removing the outer race is pretty straightforward. On some headstocks Schaublin provided two small holes at 180 degrees to each other and at the diameter of the bearing outer on the inside of the casting to aide removal. If these aren't present then the oil ring that sits in behind the bearing outer can be used to drive the it out. The oil ring has a threaded tubular extension which will need to be removed when the pulley is in place in order to fascilitate removal of the pulley. The tube can be screwed back in place and then used to drive out the outer of the bearing using a brass drift inserted through the appature for the rear bearings - the blows need to be evenly distributed of course. Alternatively, you could make up some kind of set-up with studding and tube to draw the outer race out, but it doesn't take much force to drive the outer race out as described.

@cnxunuo Жыл бұрын

@@davidsamways thanks a lot for the detailed explanation, i will certainly give it a go! I bought modern SKF for my 70, they come with plastic retainer ring, and i am going to grease fill it with modern grease, hopefully its not too sacrilegious!

@sjaakwanninkhof4872 Жыл бұрын

what is the adress of your website please ?

@davidsamways Жыл бұрын

www.anglo-swiss-tools.co.uk

@NskLabs Жыл бұрын

within 5 um? What are You gonna do, breathe on it? Factories manufactured their own mounting jigs for correct adjustment, I would just tighten it until there is no more chatter after reasonable warm up. Keep in mind if You assemble it in a very cold room You may not know if it going to bind and overheat or be too loose.

@davidsamways Жыл бұрын

If you listen carefully to what I say I'm echoing your sentiments exactly - one has to keep in mind that this is a lathe not a grinder. I've lost count of how many of these I've done and a practical approach is really the only approach worth taking.

@NskLabs Жыл бұрын

@@davidsamways You are right, I wasn't listening carefully, if at all, I just commented on "within 5 microns", which within my ca 7 years of tool making experience is more theoretical or a thing of feel rather than a measuring possibility.

@stevenrichardson7882 5 ай бұрын

Pure guess work and not the best way to do it? With the spindle vertical it’s best to tighten the locknut until the outer race just holds itself and I mean just holds itself… Then put the outer race in the headstock and assemble the spindle?

@davidsamways 5 ай бұрын

There probably are more accurate ways of doing it Steven. As I say, the Schaublin instructions do not provide a more accurate way of doing this and SKF's booklet on precision bearing adjustment would be a much better way of proceeding. However, it's a case of "horses for courses" - this is a bearing for a plain lathe not a grinding machine. With more than 25 years experience of fitting these bearings to these specific machines I've found this to be the easiest and most reliable method and produces the most pragmatic outcome. If you develop a better way of doing it then I'd be very interested to hear your experience - I'm always open-minded to better ways of doing things!