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Member postings for David Taylor

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

Thread: best machine tools for lathe
13/03/2018 10:45:02

Neil's point would explain my experience with the only brazed carbide tip tool I ever bought.

13/03/2018 04:04:31

I used the grinding jig that comes with the tangential toolholder so I assume the angles are ok.

I just seem to get better results with a normal HSS tool ground to 'about right' shape. I can also easily use a no top rake tool for cast iron and non-ferrous metal.

Re putting the upside down parting tool holder behind the work, yes that will work too but if you've made a rear tool post I assumed you wouldn't need the tool holder.

Another thing I'd recommend is a quick change tool holder. I ignored them years figuring they couldn't be that useful but bought myself one as a birthday present a few years ago and it's great. So easy to adjust the tool height to get it on center so easy to swap between tools. I never even bought more holders because I'm cheap but I'd like more than the 3 or 4 I have.

Boring bars for replacable carbide tips are another thing I've come to love. I got sick of grinding HSS boring tools (which I find much more difficult than a normal outside tool) and the little bars are great.

Thread: What did you do Today 2018
13/03/2018 01:18:36

David S has it right. We're getting solar panels so have to get a single phase or 3-phase meter put on - we have an obsolete 2-phase one at present that must be replaced. So I decided to get 3-phase and will send it up to the new workshop if it ever gets built... a process that is taking forever to get started.

The leads on the lathe caps are soldered on so I'm assuming the connection is okay. The milling machine has eyes on the end of the leads so I can't see how they were ever good connections because they were not screwed into the caps, more like staked on. One of the eyes was burned right through.

The replacement caps will have spades so I need to put the appropriate female connectors on the wires.

I'm worried I've just made the lathe motor problem worse during the pointless disassembly by crimping or squeezing a wire somewhere. The new cap is $60 AUD... perhaps I should get a cheap one, see if the sparking goes away, and replace it with a good one if the sparking is fixed.

12/03/2018 04:35:22

Got 3 phase supply hooked up to the house in anticipation of getting it into the new workshop if it ever gets built.

Took the capacitors off the lathe and milling machine motors so I can order some new ones.

Thread: best machine tools for lathe
12/03/2018 04:32:27

I bought a tangential tool holder but never really got enthusiastic about it. The upside down parting tool holder on the other hand, I love it. I recommend it if your chuck doesn't screw on.

I used HSS tools for at least 5 years (and continue to use them mostly) and only bought a set of carbide tips late last year. My lathe might be strong enough for them but I do hear the motor slowing down when I use a decent depth of cut and high speed where I assume there is less torque available. But the finish is pretty ordinary if you use them like you would HSS.

Grinding a HSS tool that cuts isn't that hard. Perhaps grinding one that gives the finish you want isn't quite so easy. I'm a very unskilled amateur and seem to be getting away with it.

Thread: Top slide std positioning
12/03/2018 04:24:35

I almost always use the carriage rather than the top slide. I know the carriage is parallel with the work whereas the topslide may not be spot on.

As John mentioned it also helps keep the topslide out of the way of the tailstock.

Thread: New Stuff You've Never Used
11/03/2018 21:07:07

I haven't used the dividing plates I bought with my rotary table yet. About 6 years on. I'll make some gears one day!

Thread: Single phase motor capacitors
11/03/2018 10:04:38

The milling machine one could have been gone for a long time - I never heard any sparking from it and only noticed because I thought I had to remove the terminal box to remove the motor from the top of the gearbox.

I’m surprised the lathe one looks so ‘normal’ but perhaps it hasn’t had time to get scarred up yet. I don’t often run at top speed which is when it arcs most.

It doesn’t sound like anyone suspects the centrifugal switch so I’ll get some new caps and see what happens.

Thanks for the advice guys.

Thread: What did you do Today 2018
11/03/2018 09:12:45

Took my lathe motor apart, put it back together, no clue or improvement except lots of sparking/arcing from a capacitor. At least I know how it comes apart and what it looks like in there now! I also can't figure out how the fan has any effect... it is on one end of the shaft but both ends of the motor are enclosed so I can't see where the fan would draw air from inside.

Thread: Single phase motor capacitors
11/03/2018 09:05:26

Hi all,

About a month ago I noticed the sound of arcing coming from my lathes motor when I started it. I took it off today and couldn't see any scorch marks around the centrifugal switch plate where the contact is.

I checked the capacitors and neither of them seemed to have loose or eroded terminals but they did show signs of heating on the insulating sleeve around the terminals.

Put it back together and onto the lathe, still arcing. I tried the slowest and fastest speeds. Little bit of arcing on the slowest speed and lots on the fastest on startup. On fastest speed I could easily smell the problem too.

I looked over the bed at the motor and noticed flashes seemed to be coming from the smaller (physical size) capacitor.

I assume I wouldn't see arcing from the centrifugal switch as it is totally enclosed.

Is the arcing because the capacitor is failing, or could it be caused by the centrifugal switch making the capacitor arc?

Can I just remove the capacitor and short the leads or something to see if the arcing goes away before replacing it?

Interestingly (to me) the milling machine motor ALSO has a problem with a capacitor. In its case the arcing has burnt through the eye terminal so it is a C section and can be loose, probably making the problem even worse.

Both machines are about 6 years old and both motors are dual capacitor motors. On the lathe I assume the starting capacitor is the problem. Is this normal?

Regards, David.

Thread: What did you do Today 2018
10/03/2018 22:47:46

While waiting for my old steel double garage to get replaced with a new purpose built workshop (luxury, I'm not ashamed) I'm giving my hobby 'quality' lathe and milling machine a work over.

With the milling machine exploded all over the bench I decided to disassemble and cleane the lathe compound slide and replaced the 3 oilers on it so they have the same sized balls (gotta look neat) and the balls actually seat home so grit doesn't fall in through them.

Things I noticed:

1. The tapered jib has a nicely finished side and a rough side. The rough side is the sliding surface that is against the dovetail :-\

2. I didn't understand what I was doing when I made the big t-nut for the quick change tool post. The way I did things the tool post is only held steady by the stud bearing on the compound slide - ie the stud screws all the way through the t-nut. I put a couple of pop marks in the bottom of the t-nut thread to stop the stud going all the way through but now the tool post just slides around because the top the t-nut flanges are not clamping properly so I need to shave .5mm off the top the nut. Which would be a job of minutes if the milling machine were together.

Thread: Getting valves to seal.
10/03/2018 22:25:50

My guess is different valves from the same supplier will be behave differently depending on how good the cutting tool was at the time etc. So a review might get a particularly good or bad example.

Given so many people have problems with them I'm guessing you just need to keep making them until you find a technique that works for you and your equipment.

I'm tempted to try the tophat/o-ring style. They sound easier to make.

Edited By David Taylor on 10/03/2018 22:26:05

Edited By David Taylor on 10/03/2018 22:26:29

Thread: Fitting new bearings to gear shafts in milling machine head
09/03/2018 10:26:24

Hi Paul,

The site I gave the address of above has a good photo that I’ll use for reference when I put mine back together.

If you’re having trouble with sticky gear changes then when you rework it take the sliding gears off the shifts and clean the key ways. Mine were burred and this caused the gear cluster to get jammed.

I’ll try to take some photos as I go. Or perhaps larneyin will post his.

Regards, David.

08/03/2018 21:30:43

Thanks larneyin. How did you clean out the gearbox?

Good to know the work is worth doing and bottom up is the way to go.

I have left the gearbox on the column. Seemed a lot of trouble to take it off and move it around.

08/03/2018 10:10:34

Will the paint and oil seals survive the heating? There is an oil seal around where the motor shaft enters the gearbox.

I might just get the shafts and bearings into the bottom then screw the lid down over the top bearings.

I meant to ask about freezing the shaft to get it into the bearing but I guess your point still stands - 20deg probably won't make a noticeable difference.

When I'm tapping a bearing into a housing do I tap around the outer part of the bearing or the inner part? I'm guessing the outer part.

Thanks for all the advice guys.

08/03/2018 08:40:20

I wouldn't say they're loose, I couldn't press them in with my fingers or anything. Would putting the gear shafts in the freezer for hours? a day? do anything without heating the bearings? I really don't want to heat the bearings - I'm sure I'd stuff it up.

The gearbox is cast iron, the pockets the bearings fit into in the bottom are like top hats turned out of steel and glued or pressed into holes in the cast iron. On the top the bearings just push into the cast iron up to a circlip stop.

My guess is when it was manufactured the bottom bearings were pressed into the steel pockets which were then put into the cast iron. There is a lot of goop around to stop leaks.

I didn't think about the shielded bearings until after I'd ordered the new ones. It could be because the manufacturer knew they were not doing a great job clearing the casting sand and filings out so safer to just use shielded bearings to get it through the warranty period.

My particular example is really poor. Burrs on the keyways stopping the gears sliding on the shafts to change speed, a bind in the fine feed mechanism, a tight spot when lowering the quill...

The 'manual' doesn't even have part numbers for spare parts or specifications for the bearings. All of them are just listed as 'bearing'. Seals are the same - they're all 'oil seal'.

08/03/2018 04:30:01

Hi all,

The time has come to refurbish my RF-45 clone. I have removed the old bearings and ordered better quality replacements. To see what I'm looking at see http://www.graetech.com/index_files/Page975.htm - I'm doing the same thing.

But I don't know the best way to fit the replacements.

Each gear shaft has a bearing at each end. The bearings are press fits onto the shaft and into their pockets in the gearbox castings. The pockets in the bottom of the gearbox are blind, the top are open.

When I lifted the gearbox lid off the shafts and their bearings came with it which makes me think the lid bearings are a tighter fit than the bottom bearings.

But I don't think putting it back together that way will be easy because there is no way to align the bottom bearings with their pockets because they're going into blind holes

The only way I can think to go is to press the bearings onto the shafts first. Then press the shafts into the bottom pockets in the gearbox. Then fit the lid and tighten it down onto the bearings, aligning them through the holes in the top.

Or should I press the bottom bearings into their pockets first, and then the shafts into them?

Either way it seems to me I'll be putting stress on the bearings.

Regards, David.

Thread: Intel PCs to be reduced in speed by up to 30%
07/01/2018 22:54:29
Posted by Ady1 on 07/01/2018 11:59:18:

Intruiging to watch society being manipulated by semi truths and wild exaggeration though

They're a difficult couple of bugs to explain and I guess no media organisation wants to open themselves up to "you said it was a storm in a teacup".

I think said media organisations are enjoying having a sky is falling story to report on, especially in a slow early January. They haven't had it this good since Y2K.

I'm annoyed about how much extra power the fix is going to cost though. Given all the other ways people have found to get into our computers, and the generally insecure state of OSs and application software, exploiting these bugs looks like doing things the hard way.

07/01/2018 22:48:33
Posted by SillyOldDuffer on 06/01/2018 18:33:53:

Tracy Kidder's 'Soul of a New Machine' is a thoroughly readable book about developing a bleeding edge 32-bit processor circa 1980. As I recall it's good at explaining Microcode.

That's a brilliant book. I read it years ago and always wanted to revisit, then one day I looked in the books at the tip recycling shop and there it was!

No idea why a copy was out here in regional NSW but my gain. smiley

07/01/2018 06:00:05

The chance of most people being affected by either bug is pretty slim and the press coverage around it is cataclysmic.

The cure is probably worse than the disease in this case - the overhead incurred in large data centres after the fixes are applied - as compared to people browsing the web or watching movies - could use a lot of extra power for the same workload.

With this and the Management Extension stuff last year Intel is having a hard time of it. Not that I feel sorry for them.

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