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Member postings for Pete Rimmer

Here is a list of all the postings Pete Rimmer has made in our forums. Click on a thread name to jump to the thread.

Thread: Wandering mill table
25/10/2021 18:35:55
Posted by Steve355 on 24/10/2021 23:08:18:

Thanks Pete

I’ve examined the lead screw and it isn’t obviously bent, but I will take another look.

there is a stiffness in the handle that always occurs in the same place in the turn. I think that whoever is causing it, is related to that,

cheers

Steve

That can only be a bent or poorly manufactured screw.

24/10/2021 22:29:41

If the table is rotating simply from turning the handle either the ways are worn or the leadscrew is bent. It's also possible that the leadscrew nut is machined slightly too tall and the bed is riding on the leadscrew somewhat. Check for a bent leadscrew by turning it slowly by gripping the wheel not the handle. If it's bent it will move your dial regardless of how it's turned.

Thread: Hi all, newbie with first lathe, rare one i think.
22/10/2021 20:27:20

The bearings and shafts are all gallery fed which are filled by spalsh lubrication so the most important thing is that there is at least the right amount of oil in there or in any case enough so that the splash system works. If in doubt I always go for ISO32 hydraulic oil.

19/10/2021 19:02:56

What gears are on the machine Wayne? The 25, 42,46 and 64 aren't part of the original set but you shoud have a pair of 50's and a pair of 20's.

19/10/2021 12:30:01
Posted by Michael Gilligan on 19/10/2021 10:45:09:

A decent photo of the Gewindesschneide Tabelle would help … but [to me] it looks likely that the leadscrew is Englisch

.

3bff08f6-f871-418c-b9ef-4234f6c66f1a.jpeg

.

Credit: **LINK**

http://www.lathes.co.uk/union-werk/

MichaelG.

Edited By Michael Gilligan on 19/10/2021 10:46:47

4 tpi leadscrew on that lathe Michael.

Thread: Painted granite surface plate
19/10/2021 10:40:00

I have the coarse brown scotchbrite and have use it on adly gummed up granite. I couldn't raise any appreciable amount of dust with it. When I'm cutting a plate however it gets everywhere.

They do wear, that's a fact, but not from a single scotchbrite cleanup. Not so much that you could easily measure.

Thread: What taper does this mill use
18/10/2021 20:56:34

Good result Stan yes

Thread: Painted granite surface plate
18/10/2021 19:13:38

You won't affect the accuracy with a quick go-over of scotchbrite especially if it's the whole surface. I sometimes recondition granite plates and to remove 10 microns generates a lot of dust. You would certainly notice.

My experience is that the Chinese plates tend to be pretty damn good, certainly exceeding their certification. Much less risky than buying a used plate of any grade.Even the last 'in calibration' plate I bought was nowhere near spec.

Thread: cutting spur gears on a mill
11/10/2021 18:39:07
Posted by Andrew Johnston on 11/10/2021 11:04:15:
Posted by Pete Rimmer on 10/10/2021 21:20:16:

It produces facets it just doesn't produce flat ones......

Unfortunately that is mathematically incorrect. A facet is a feature of a polyhedron, generally of one dimension less than the original object. Assuming that we're discussing 3D Euclidian geometry then a facet will be 2D. By definition that means it exists on a plane and so will be planar, ie, flat.

Here's a thought experiment. Let's assume we hob a spur gear of zero width, so the hob teeth only cut when they cross the plane of the blank. As the hob enters the plane of the blank, and exits the other side, it will cut a reproduction of its shape, ie, straight sided. Since the blank is of zero thickness the cut time is also zero, so there is no rotation of the blank during the cut to consider. What will the resultant shape of the cut space be; a series of straight lines, or a smooth curve?

Andrew

I don't do theroetical debate very well I see it as wasted energy. I take your point about the use of the term 'facet' but it's the most fitting terminology I could come up with.

Basically my hobber when it's feeding has very little infeed in fact the feed handle moves like clock's minute hand. Almost all of the 'movement' is the hob teeth passing the blank whilst the blank is constantly rolling so whilst a zero-thickness blank might theoretically receive a flat facet cut ANY thickness of blank will be cut via a simultaeneous action of helical-motion teeth passing through the part whilst it's rolling. It will generate a curve, not a flat.

10/10/2021 21:20:16

It produces facets it just doesn't produce flat ones. In a similar vein who would argue that a lathe can't produce a smooth round finish even though it's using a tool that inherently cuts a helix?

It's all a matter of degree.

10/10/2021 20:08:35

The gear blank does not stop rotating for each hob tooth to make a cut, so each cut is made not with a flat facet but with a slight rolling action.

Think of it as analogous to filing a curved face in a part. The file is flat but you generate the curve by rolling the file as you push. Hobbing is similar.

Edited By Pete Rimmer on 10/10/2021 20:09:44

Thread: What taper does this mill use
07/10/2021 19:04:29

Mine was done in 2009 by John. I did have the details on email but they have long gone. I think he used EN40 for the end slug, he machined a parallel pocket in my spindle end, pressed in the slug then machined it to size for the R8 collet. When I fitted it up there was a tiny bit of runout so I tilted the head over to the R8 taper angle, put a lathe tool in the mill chuck and took a skim cut to make the taper run dead true.

https://bbs.homeshopmachinist.net/forum/general/35047-herbert-mill-spindle-r8-conversion

Worth noting that the Herbert spindle through-hole does not quite have the clearance for the R8 drawbar but it's only a few thou so he made a slightly undersized one for me and it's been in use for 12 yrs now. I have to say I can thoroughly recommend it as a modification it opens up a wide range of usefulness being able to use the R8 tooling.

Edited By Pete Rimmer on 07/10/2021 19:04:50

06/10/2021 18:27:20
Posted by Stan Tomson on 05/10/2021 10:56:37:

Hello everyone,

I have a 0V mill with 6 original collets and would like to fit an Clarkson Auto lock. As far as I know my mill does not have the Herbert Easy Taper. I purchased a Clarkson Easy taper auto lock some time ago but it does not fit. The machine is very well made and in excellent condition so I do not want to get rid of it.

Hope that someone can offer some information.

Hello Stan,

I also have an 0V and it also came with the 6 collets in a wooden block. I could not find any other collets or informatio on the taper type and came to the conclusion that they must be particular to the machine.

John Stevenson modified my spindle so it now takes R8 collets which are plentiful. It involved pressing a slug of steel into a recess that he cut into the end and machining the R8 taper into it. I'm very happy with the result and have been using it for quite a few years

I considered adapting another chuck like an autolock to it but decided agaist it to give as much z-height as possible and also keep things as rigid as I could. I think it was a good choice and woud suggest you consider the same.

Does your machine have one Tee slot in the bed or three?

Regards

Pete.

Thread: Unwanted Taper
04/10/2021 20:08:34

Well done Steve it;s nice to see people thinking about and tackling a problem themselves without having to have their hand held all the way.

03/10/2021 14:42:32
Posted by Steve355 on 03/10/2021 14:38:44:

Thanks for all the comments

when I remeasured my work this morning the taper was back 😢 no idea how but it clearly is

So I thought I would try what several have suggested and turn a new piece of brass rod without tail support and try shimming the tail end to get it parallel. So I did that…

my first measurement was 935 at the headstock and 961 at the far end. I added shims tightened it back up and took several more cuts and measurements.

now I have quite a lot of shim (about 030) and my level (love it or hate it) indicates a significant amount of twist that wasn’t there before. Headstock:

aaae370c-c058-4a59-9949-1b604dc427a0.jpeg

tailstock:

d23d304f-7c1f-4d03-8121-dbd673af3d59.jpeg

shims :

9dc3a77a-32b2-4332-b69e-59d8eae67c4d.jpeg

my latest measurement is 908 at the headstock end and 920 at the tail end, so quite a lot better but nothing like close enough. I am starting to think this is nonsense, because I seem to be adding twist to try to reduce taper. In addition the finish is bad at the far end of the bar, which is what one would expect I believe, and probably enough to account for the taper.

basically it doesn’t seem to be working. I’m worried too I could damage the lathe.

arghhhh!

Steve

Steve you might well damage your lathe If you keep that up. You don't say what lathe is actually is. It could be that your bed is level but the headstock is not pointing straight down it.

Thread: Crankshaft Factory
03/10/2021 10:50:08

The packaging says steel crankshaft but the chips and sparks say iron

Thread: Unwanted Taper
03/10/2021 10:46:40
Posted by Tony Pratt 1 on 03/10/2021 10:25:00:

I've always used the method as advised in the Myford handbook where you actually turn a piece of metal & shim the tail stock feet to get parallel. Loads of threads about this subject on here & on the net. Last time I saw a machinists level was 2 years ago & yes it was gathering dust in a cupboard.

Tony

That should be plenty good enough for most bench lathes.

If you have a machine with 2 pedestals like a Bantam, the first thing to do sould be to level the bed and fix the feet to the floor, with shims of required to achieve level. I rebuilt a Bantam and as an exercise I put a dial gauge on the saddle and against a part in the spindle, then I moved it about on my workshop slab - the dial gauge swung all over the place just from the variations in floor level and the lathe stood normally on it, and my floor isn't bad at all. It was quite the eye-opener.

03/10/2021 10:12:02
Posted by Steve355 on 02/10/2021 22:17:10:

Ok, you are right, it’s all me. I did that and it’s very close to parallel - about 1 thou out. I checked again with the micrometer and got the about .5 thou. Luckily this is the “beginners” forum so I am allowed to be an idiot.

Why did it give me an incorrect reading on the other side then?

7cf8a1fd-97b7-465d-a86f-2f6592175cf3.jpeg

20b96b3d-dbd4-4904-b1a1-97ad13689d0f.jpeg

45027214-d329-4cf1-b986-ab410a526d17.jpeg

e4342679-72df-431c-9ef6-a44bf62032c6.jpeg

Hard to describe in words coherently but easy enough to show.

Your dial is not actually measuring taper as such, I mean it MIGHT be or there might be a taper when it's showing no movement. To measure taper with a dial you'd use a comparator stand.

With the dial on the front and mounted on the saddle it is following the same path that the tool took when it did the cutting. It should therefore give the same reading all along the length. If there is any wear or twist in the bed then where the tool was caused to move away from the centreline of the part, so would the dial point. It would show no change.

With the dial on the opposite side of the part if there was wear or twist causing the tool to move away from the centreline of the part then the same wear or twist would cause the dial to move TOWARDS the centreline which would give a rising reading.

02/10/2021 21:10:42

Put the mag base for the dial gauge on the front of the saddle and do your measurement again. That way the dial gauge will be following the path of the tool and should read zero all the way.

That gauge setup is a poor way to check for taper if that's what you're doing Steve. You should be using a micrometer to take measurements at each end of your cylinder. The dial gauge reading can be affected by twist or wear in the bedway.

Thread: cutting spur gears on a mill
02/10/2021 12:19:19
Posted by brian jones 11 on 02/10/2021 10:29:40:

Caustic commentators on this thread must remember its Title "Spur Gears - a rogue method"

If you want to pursue the conventional route on this topic by making precision standard gears then this thread is definitely not for you - it has nothing to offer that mindset, walk away.

With respect Brian you only started the thread, you don't get to dictate who may contribute or how. If that's what you want, write a blog. This is a community and participation is encouraged.

If there is an obvious flaw in the concept, the application or the result then it absolutely should be pointed out so that those who come across this thread in the future don't assume that a poor practice is perfectly acceptable just because it's gone unchallenged.

Edited By Pete Rimmer on 02/10/2021 12:19:52

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