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Okay now the next problem my controller will only accept 12.4 or 12.5 not enough digits to put in 12.452 but there is another setting for cone ratio that overrides other settings but I don’t have the first idea how to get the cone ratio, a google search didn’t help anyway not sure it would help without trying anyone know how to work out the cone ratio ?

Dell

Thanks for replies the 1.725 was a typing error I don’t know how the 2 got in there, will blame it on my age anyway I have just found a calculator online and the taper length should be as Mike said 12.4mm giving a taper degree of 8.033 so that’s where I was going wrong , it just goes to show that it’s worth doing something that we have never done before using a bit of scrap, anyway I will cut another bit of scrap aluminium again tomorrow just to be sure.

Many thanks Dell

I am hoping someone on here can help me , I have the soft blank to make an ER11 collet chuck for my Pultra and I am unsure about the internal taper, according to google search the included angle should be 16deg but when I cut the taper in a bit of aluminium using Rocketronics, large end 11mm and 7.5mm small end overall length of 17mm so putting -Z17 and -X1.725 being half the difference between 11 and 7.5 I get 5deg ( so 10deg included) and not 8deg ( 16deg included) what am I doing wrong ?

I want to get this sorted out before I do it on the proper arbor.

I did get the thread name wrong

**LINK**

I restore torsion clocks and mostly they use BA threads from about 1915 to mid 50’s when they are mostly metric , before approximately 1915 they are Thury or lorence ( think I spelt it correct) but as every thing there are exceptions, I can’t see using metric as a problem modern clocks modern threads.

Dell

i did get name wrong it’s Lowenherz

Edited By Dell on 01/10/2023 08:25:31

Been getting my head around the Rocketronics Els today because I wanted to make a graver rest for the Pultra 17/70 I am restoring, it could have been a bit better but I am relatively pleased, I would have liked to have less curve but I couldn’t work out what parameters to put into control so if anyone has the same bit of kit and could enlighten me that would be great.

As i already had a base I made for my graver sharpener I decided to use it so it will do both jobs, just the clamp and clamp bolt to make.

Dell

That’s quick and good news thanks for your replies.

Dell

Hi all

It may be just me but I find all the permutations of indexable tool holders and inserts very confusing ( may be my age ), I need to make something quite large well large for me anyway out of brass , I usually only make brass parts using the hand graver but as the part is to large and I have the Myford equipped with the Rocketronics ELS I thought I may as well use it because the part I need to make is a radius, anyway the problem is I have been using a glanze SCLCR holder with

CCMT060204 inserts and been getting brilliant results on steel and stainless but I need an insert with negative rake for brass and I think aluminium, can I get an insert with negative rake to go into the holder or do I have to buy a different holder.I had been using eccentric engineering tool but I found that although it was good for most things when using the ELS it was okay for the first few cuts when it started getting more than 2 mm of shoulder it would jam and stop the lathe also damaging the part in the process so I sold them and I don’t get any problems with the above tool and getting a superb finish.

Just purchased a Pultra 17/70 with leaver tailstock and 160 collets yes 160 it had been used from new just to make fishing floats so you can imagine how much wood dust there was, I have stripped it to give it a good clean and revamp and to my surprise it has roller bearings, I didn’t think they made them like that , I know when Smart & Brown took over they made them with roller bearings but they didn’t have oil sight glasses and this one has oil sight glasses, oil cups and grease nipples so the only thing I can think is it was made during the change over period from Pultra to S&B, I am going to order some new Timkin bearings because the old ones are very dry so may be worn.

I have all the conflex collets soaking in Evaporust and will do the others later they are not conflex but they are a good fit and correct thread so will have to look in book to see if I can find maker.

Dell

It wasn’t along its length it was is the side to side that dished ,as I say it’s not a problem with this part , I was just wondering for future reference when something more critical in size is needed, I have since measured and the slot I cut in first 8.6mm wide now measured 8.67, although it is less the further in towards the closed end but that would make sense as more material there. so not a great amount but if it was some critical part 0.07mm could make a difference between fit and not .

Dell

As I said in the original post , I squared it off meaning I milled all four sides and both ends but it looks as though I didn’t milk enough off both sides to release the stresses.

Dell

Thanks for all the replies, so next time ( if there is a next time ) I will coat in borax and heat to red then let cool.

Dell

I have just got rid of my Mercedes/ Renault because if you go to buy a Mercedes you don’t want 1/2 a Renault, anyway I now have a Lexus hybrid was told not to misplace the key fob because a replacement is £599 including coding.

Dell

I am in the process of making a copy of Levin’s diamond watchmaker graver sharpener ( see first picture), I started by making the arbor to mount the diamond wheel to my Pultra then moved onto the base that fits onto the mounting point where the tool rest goes.

I started by milling the steel square ( or should that be oblong ), then cut a slot 4.8mm deep X 8.6mm wide then to cut the T slot I had to use a woodruff cutter because I couldn’t get a T slot cutter small enough, very slow going on my very small Warco WM12 , as I am going to nickel plate to guard against rust I needed to sand to remove tool marks but when I offered it up to the sander it only sanded the edges not the centre it’s not a problem with this part because it’s only the base but for future reference it would be nice to know if cutting the T slot was the cause.

I haven’t been able to find anyone with the tool to be able to get measurements so I am having to do it best I can.

Dell

Dell

Edited By Dell on 03/08/2023 17:16:15

Thanks for all the replies and suggestions,The tool holder is less than 6 months old and I put the finished part in to chuck so I could take a picture of it with tool up against the shoulder and I can see I have more clearance one side and not much near the shoulder.

Dell

The readout goes to 40mm every time that tool bit has a radius corner so should I use a sharp corner ?

This is the tool setup.

This is what I was making.

I have a problem that I’m hoping someone has an answer or suggestion, on my Myford 10 while using the Rocketronics els when my tool bit gets to a shoulder it jams, EG for example say I have a length of 25mm mild bright steel that I want to turn down to 10mm say over a length of 40mm, in the control I I input-40mm for Z and - 7.5mm for X , using a eccentric engineering tool the first few cuts are fine although I can hear the extra cutting up against the shoulder and with each cut the extra cut seems to get louder and the last 1mm or so before the shoulder is very rough and a Matt finish but it’s when the part is getting towards the 10mm it jams , I have checked to make sure the tool is square to headstock .
Thanks in advance Dell.

I know this is an old thread but if anyone needs a wiring diagram to convert a jack industrial sewing machine motor to a potentiometer including what resistors and pot to use I have it, I fitted one on my Pultra 17/70 under the bench and it was the best thing I did torque amazing even very slow, I even used the cast box to put the pot in just make sure it and everything is earthed.

Dell