Member postings for Peter Wood 5

Why bother with a tacho?

A number of reasons, and respecting contrary opinions, they come down to personal preferences.

I use the tacho on my mill all the time. I have developed a mental picture of what speed to start with for any particular combination of tool, metal or task. I felt I was lacking that info on the lathe.

However, and primarily, I fancied the project.

But back to my main question - how critical is the balance hole on the large pulley.

Peter

As with several of the previous posts I have fitted an inverter to my Myford S7 but wanted a read out of RPM. So I purchased the cheap tachometer off eBay used by others.

The Hall sensor provided is far too big to fit anywhere in the belt drive housing so I replaced it with an A3144 chip housed in a short strip of carbon tube.

I noticed that the large belt pulley had a small hole drilled opposite the oiling nipple so I used this to hold a small magnet (about 8mm diam). The thin carbon tube holding the sensor is fixed to the housing adjacent to the pulley with a small clamp. All works fine.

But I am having second thoughts!!

How critical is that small hole to the balance of the spindle assembly? Am I likely to put undue stresses on the rear bearings?

Any views?

Peter

I have spoken to the friend who gave me the tools and he confirmed what Bill posted. They were used for cutting very accurate keyways.

Apparently a conventional spiral fluted slot drill produces a slightly v shaped slot as the spiral pulls the tool sideways, removing a bit more metal near the top of the slot

Thanks for the replies.

I was told that many of the tools I was given had been reground several times so it would explain why old style tools were in the collection.

I will probably touch them up on my new Acute Tool Grinder before testing them on some scrap.

I have been given an assorted collection of end mills and slot drills from a closed engineering works.

Amongst them are some slot drills with straight flutes.

Can anyone tell me what they are used for and why.

Finished fitting a DRO from EMS on my Myford as detailed in a recent issue of MEW.

Making the read head mounting brackets was time consuming and fiddly especially as I cannot easily access the rear of the bench mounted lathe.

However the biggest problem came when I tried to refit the dismantled cross slide which would only go on about 1" before hitting an obstruction. Eventually discovered that the groove in the feed screw had to engage with a pin on the power cross feed. I learnt a lot about the lathe construction in this project.

There was a project in the Oct 2012 edition. ' A Universal Device for Cutting Radii on the Mill '.

A very elegant solution but as you said probably not worth it for just a couple of items.

Just cut my first matching internal and external threads which mated perfectly. Well pleased. Now for the threads on the lantern chuck.

Thanks for all your help.

I have also just made my first attempts at screw cutting with limited success.

However when working out how to use the QC gearbox on my S7b I recalled that the lathe came with a loose set of gears. There are eight in total numbered 30, 35, 38, 40, 45, 50, 55, and 60.

Can anyone tell me what they are for?

Jason and Jim

Thanks for the advice. That is exactly what I needed to know. I will use the metric tips at 16 tpi.

I will test first on some scrap ali bar.

For info here is a photo of the tools showing the sizes.

Peter

Despite owning an S7b with QC gearbox for 8 years I have never attempted to cut a screw thread. The Lantern Chuck project seemed like a good opportunity to start.

It calls for a metric ( M30) 1.5 mm pitch thread, internal and external. So at Warwick I purchased 8mm indexable internal and external cutting tools with metric and imperial tips.

However having got home and examined the tool bits it looks like the maximum thread depth I can obtain is about 1.4 mm with the metric tool.

So the question is what TPI should I select on my imperial Myford

Eric and Nick.

Thanks for your replies. By trial and error I found that a 2 BA oil nipple fitted perfectly. The 2nd change gear stud is also fitted with an oil nipple.

The bolt was probably used instead of a nipple as it locks the retaining lever for the second gear. Anyway I will contact Myford to see if they do spares.

Thanks again.

Peter

I have broken the hollow bolt which retains the 1st stud gear on my Myford Super 7.

Can anyone advise me what sort of thread it is so that I can fabricate a replacement.

Thanks.

Peter

Edited By Peter Wood 5 on 17/10/2017 21:51:48

My second hand Myford S7 came with a Dickson type toolholder. I have since bought quite a few toolholders from Soba, Chronos etc but all have the limitation that I can only use 8mm tooling. When such tools are used there is less than 2mm horizontal clearance between the toolpost flat on the compound slide and the bottom of the toolholder. This means that it is impossible to get 10mm tool on centre height.

I did inherit a parting tool holder which has a rebate across the toolholder base presumably because of this limitation but all my other holders are far too hard for this treatment.

Has anyone found a solution to this problem?

Michael & Neil

Thanks for the info. In the event Neil's reference to adaptors gave me an idea. I had a couple of air brush gas canister fittings which I would never need and I was able to pull out the the threaded brass hose coupling from the plastic. This has exactly the correct diam to solder it into the copper pipe feed to the valve chest. Problem solved!

Once again thanks.

Peter

I have just completed a Stuart Half Beam and would like to run it from my small airbrush compressor. The hosepipe to my air brushes, such as Badger, has a common coupling. Can anyone tell me what the tread is so that I can make a coupling to the model input gland.

Thanks.

Peter

Maurice

Thanks for the suggestion. However I completed the task in January using the chain drilling, fretsaw, and mini-file technique. Nevertheless it is a an approach I will bear in mind for future projects.

Presumably you cut the slots before making the bearing housings on the end of the crankshaft and also before milling out the tuning fork?

I think I made the slots as the last step in the crankshaft fabrication.

After a long break during the summer, when the prospect of making the Watt regulator put me off, the model is nearing completion. Just a few minor parts to produce (including the regulator butterfly valve.

Peter

Mick

I also bought a couple of these when they were on offer a couple of years ago and I think they are excellent. I also use the IKEA lights and find the gooseneck far to limp - especially near to the vibration of my mill.

The only problem I have encountered is that they are very hot and I managed to melt one of the rubber grips on my mill when the light got too close. If the new ones are fitted with LED's then I will cerainly buy another pair.

Peter

Success. I have just made a perfect trial slot in about 15 mins.

I adopted Jo's approach. I chain drilled a series of 3/64'' holes and then joined them using a piercing saw. I then swapped the blade for a larger size, more like a fretsaw and opened the slot until I could just fit one of the tiny files I bought at Ally Pally. Five minutes careful filing and I had a perfectly rectangular slot.

No setting up the mill with a tiny cutter and no stress as I waited for it to break.

Suddenly that con rod does not look half as intimidating.

Thanks for all the suggestions.

Peter

I am now back from Ally Pally with a considerably depleted bank balance. However I did find some really tiny needle files which are less than 1 mm thick and some piercing saw blades. I don't think they are particularly good quality but they might just do the job. Also got some 3/64 silver steel rod so I can also try the D-bit approach.

If I have no success on a trial piece then the search for 1mm screw end slot mills will have to continue.