Member postings for Nige

Today has been about getting machines in the work shop broken down into more easily movable 'lumps' ready for the move to Peterborough. Floor mounted pillar drill and the big Record band saw plus the Record wood turning lathe and the ML4. Taken the Axminster Jet dust extractor off the ceiling. The process of getting everything else collected together and into containers is still ongoing

As the workshop is in the garage which is leasehold I am having to put it back to its original state so the extra mains sockets I put in have had to come out: shame really as the new people would probably have welcomed the additional sockets but Ho hum.

Can you change to a smaller nozzle at an appropriate point to print finer detail ?

Mmm, I hadn't considered that the design might not stand up to the increase in speed. Ill stick to sharp tools

Thanks Ady1: doing the calculations I can get 800 rpm if I put a 6.8 inch pulley on the countershaft. Have to work out how I would either change belts or tension the existing belt that would be too long on the smaller countershaft pulley. The motor pulley is a twin so moving the belt across and tensioning is likely to be easier.

Thanks Clive. I would have to do something with the countershaft pulley gearing to get up to 800 RPM but it is doable as there is easily room on the countershaft for another pulley.

Having measured the diameters of the pulleys on the Myford ML4 I have used an online calculator to find the mandrel RPM in each of the 3 'gears' available. RPM range appears to be from approx 500 to 200 RPM. Does that sound like the likely range for this machine ?

HillClimber: BSF nuts available from KBN Fastners. Just got 5 x 1/4 BSF for £1.20 delivered. No connection to firm other than satisfied custometr etc.

BIG glider competition starting at Lasham, possibly today and over next few days Andrew.

In another thread I highlighted a minor problem in adjusting the compound slide. The hex head of the clamping bolt is rounded off because of its proximity to the slide which also necessitates the use of a small diameter washer. Wear on the the slot means the washer quickly becomes cup shaped! You can see the problem!

First thing was to change the hex bolt for a cap head bolt, then sort out a washer. The washer needs to be thick enough to resist squashing into the slot irregularities and fit up close to the edge of the slide at one end of the slot while still being wide enough to span as much of the slot as possible and give enough support to the bolt. I made some measurements and decided an eccentric washer would do the trick.

I didn't have a piece of steel bar of sufficient diameter but I do have some large coach bolts the heads of which make a good start. I turned down the square behind the head, then faced off the dome of the head and put a chamfer on what would become the 'top' of the washer. At this point I removed the 'head' of the bolt with a hacksaw as I'm not confident enough to part this off at the moment.

The washer needed to have a clearance hole for 1/4"BSF bored into it but it needed to be closer to one edge than the other, eccentric in other words. I measured and marked the position of the hole and mounted the piece in the 4 jaw, centre drilled it then opened it out with a smaller drill and finally with a 1/4" drill.

I then faced off the washer to clean up the hacksaw marks and reduce its thickness. It was really close to the chuck jaws on the final cut.

Fits a treat, Jobs a goodun

Very pleased with this. Although it is a relatively simple task it allowed me to put a few techniques together to make my first useful article and improve the lathe a little.

From concept and donor bolt to finished article; two or three happy hours in the workshop

ega: Yes enjoying the book once I got past all the technical stuff that takes up the first 116 pages. Not a complaint as I can see info there that will be useful in the not too distant future. Glad I bought it and I am re reading sections that are currently of use to me. Martin Cleeve does seem obsessed with the time it might take to do something but his background seems to be a production one with lots of items having to be made economically; again not a complaint as that environment generates good ideas which he has the talent and experience to exploit. Hurry is not what I am about

By coincidence I came across this yesterday while reading "Screw Cutting In The Lathe" by Martin Cleeve. No mention of bar tensioning effects or anything other than locking the tool bit in the end of the holder. Hope it's ok to post this picture. INSERTED BIT TOOLS...para refers.

Wow, didn't realise I would set of such a train of comments! Having managed to cut a very poor thread by the 'suck it and see' method I resorted to a Tubal Cain video where he says that 29 degrees is actually the correct angle, for reasons he isn't going in to on an introductory video I guess. I'll not argue with him or you guys about that.

My further investigations show that I got several process's wrong in my first attempt. I had wondered how to get the tool back to the beginning of the thread without it losing 'register' with the thread and my thought process had lead me to bless the existence of the tumbler reverse as that was an easy way to get the carriage back to the beginning without disengaging the half nuts at all! I had to read through 70 plus pages of Martin Cleave's 'Screw Cutting In The Lathe', which was delivered today, to find out that this is a big 'No No' ! I am still trying to work out the reasons why in my head but I'll get there eventually. Looks like a reason too source a motor reversing switch though.

I am waiting on the delivery of a thread gauge as I suspect my MK 1 eyeball method for aligning the tool at 90 degrees to the work may leave something to be desired as tubal Cain makes much of the need for precision in that process.

The dials on the cross slide and compound are not easy to read and are not of the resetable variety and I think I am going to have to write down the value on the cross slide every time before I back it out as I just know I will forget it. Also glad I fitted a thread dial indicator a little while back.

On the thread dial indicator: when I try to engage the half nuts on a particular number the indicator always runs a little past the number and by the same amount. I believe it is possible adjust this out by inserting washers on the stud the indicator is mounted on, I suppose to change its linear relationship to the leadscrew.....does that sound likely?

Trying to get to grips with thread cutting on the ML4. The compound slide has no protractor markings so setting angles is problematic. My solution was to use the combination square to measure the angle between the edges of the cross slide and the compound. Unfortunately the design of the combination doesn't allow me to get it against both the relevant edges at the same time.

I was able to fit a pair of parallels against the edges so I set an angle of 29 degrees on the combination square the put the parallels against the edges and clamped them with a tool makers clamp,

this allowed me to set them against the cross slide and compound edges.

The compound is barely to rotate a full 30 degrees and clamping it down is difficult as the hex headed bolt has it s flats right against the casting which accounts for the rounded corners! Changing it for a socket headed cap screw is the next move.

Today I bit the bullet and tackled cutting my first thread. It was to be 1/4 BSF. Another thread relates how I sorted out getting the gearing right with a bit of help from my friends. I don't have any 1/4" stock but I do have some odd bolts of a larger diameter so I set about turning one of them down to .250" I think I have discovered that .258 is too big, I'm not sure what the tolerances are for max OD of a thread but I think .258" is a no go.

In turning the diameter down I also discovered that my turning is producing a smalller diameter closer to the chuck, about .0015" over 2" so need to revisit the headstock alignment at some point, but Hey, I'm cutting metal😊 Having got my stock down to a nominal 1/4" I went looking for a thread cutting tool......What's the angle of a BSF thread mmmm book says 55 degrees and the only thing I have to measure angles is a Starrett combination square with an adjustable angle wotsit. I marked two 27.5 degree lines on the rest on my grinder and odified a tool in a piece of HSS. The faces all sloped slightly down and back from the tip so I reckoned I probably had enough clearances.

I know there is a method for cutting threads by setting up half the angle on the compound slide and feeding on the cut from there but a) my compound slide doesn't have a protractor engraved on it (though I could have used the combination square) and b) I couldn't remember what the technique was. So I stuck with mounting the tool at 90 degrees to the bar and feeding the cut using the cross slide.

Then along came all the fun of working out the best way to use the half nut and the TDI...Oh yes, isn't a tumbler reverse useful 😀 Anyway, I started removing metal and it started looking like a thread but as the cut got deeper the cut started sounding decidedly "graunchy" and despite only winding on a couple of thou at a time the thread started looking worse. I have no idea what sort of steel the donor bolt was and maybe cutting a thread on 1/4" stock 2.5" from the chuck was more flex than there should be but let's just say that looking at it it was only something a mother could love 😳 Of course,, when it came to trying to see if it would fit the only 1/4 BSF nuts I have are holding the head stock down! A 1/4" die struggled to get on which is why I started thinking the oversize diameter might be problem.

Well, all that learning took me about 3.5 hours and I have had great fun, exercised my brain more than I have in a good while, learned a lot about my lathe and about the techniques I need to go back and investigate again but more to the point, I finally got on and cut something, thank you everybody that has helped me get this far 😀👍

Edited By Nige on 10/08/2017 22:08:09

A bit of confusion introduced by referring to the ML7 Handbook as it says I would need an 'Idle 70 wheel' which suggests the need for a 70 tooth gear which I don't have. The table from the ML4 booklet only refers to an 'Idle Wheel'. I finally phoned Tony Griffiths of lathes.co.uk asking what the equivalent gear is on the ML4 and he explained that in this instance the 'idle gear' can be any spare gear I have that I can adjust to fit in the space between the driver and the driven gears. back to the lathe after tea

JasonB: Thank you, only just seen your post which will do the job as well

Edited By Nige on 10/08/2017 18:02:40

Thanks Jon: It looks as if the gear they term 'Mandrel' is the interchangeable gear on the end of shaft that also carries the Tumbler reverse gear. Those diagrams in the ML7 handbook make things a bit clearer its a shame they didn't do that level of information in the ML4 booklet which is where the Screw cutting table comes from. Ill go and have a look see.

Russell: Thank you. As mentioned above the table comes from Myford sales booklet for the ML4 which is very short on other useful info! Fortunately it looks like the ML7 Handbook is similar enough to get me where I need to be

Help please! I am trying to set the ML4 up to cut 26 TPI (1/4 BSF) I have the screw cutting table, photo below, but I am confused in identifying the various wheels under the column headings. I'm not sure which is the Mandrel gear, I'm guessing it is the one with a 25 tooth gear shown in the second photo below.

The first stud I believe is the one that currently has a 50 and 20 tooth gear on it and the 2nd stud has the 55 tooth with a 20 tooth behind? The only thing I am sure of is the 65 tooth lead screw gear which is the correct one anyway.

I believe the 'idle wheel' needed on the 1st stud (from the table) is a 20 tooth gear but 1st stud has two gears on it at the moment one of which is a 20 tooth, what do I replace the 50 tooth on that stud with? For the 2nd stud the table is blank, does that mean the 2nd stud has nothing on it? I am completely at a loss as to what is going to go where !!!

EDITED...Deleted post. Georgeneer made my point and did it first and with a picture

Edited By Nige on 09/08/2017 20:40:50

Andrew: What sort of steel do you use to make your studs please?

JasonB: Thanks but I don't have any 1/4" stock. As I would have to order it in I might as well order studs. I would make my own if I had stock but with the lathe in bits I didn't fancy risking the wobbly thread syndrome

Jon: Thanks, I have looked at those guys already and they don't do studs with the right amount of thread on each end.

Might have to order studs too long and continue threads down,