Member postings for paul sims

Dear All,

I have noticed a typo in my report with the pictures, The wire thickness is 6mm square not 60, as this is a stupid dimension I am sure every body realized my error, sorry!

Many thanks for the handy feedback, I am sure that anybody else that wants to cut Polystyrene will find all the advice and suggestions in this post very helpful.

Regards, Paul.

Dear Circlip (Ian) and Jon, The polystyrene being cut is part of the interior wall construction and therefore is non-moveable and the best that can be done is to ensure plenty of windows and doors are open and to limit the time of cutting.

Regards Paul.

Dear Jon and Emgee,

Thanks for the Vidaflex Sleeving supplier info and the important health warning.

best regards,

Paul.

Dear All,

I have finished my Polystyrene cutter and tested it on some scrap pieces, The building extension has been postponed until the spring of 2018 so it has not done any proper jobs as yet.

It has two handed operation to ensure accuracy of cuts and arm fatigue, the thumb of either hand can hold down the ON button, it heats and cools very quickly, there is a red neon to show when it is heating, the width and depth of cut is adjustable, it has two cutting wires one for the fitting of conduit and the other for the box for the sockets.

The Voltage output is 1.4 volts, the cutting wire is 14 guage Ni-Chrome, I found this the best for cleaning after using, the residue scraped off with a finger nail, other metals required the use of a tool. The secondry winding was eventually 7 turns of 60mm square wire that is normally used as earth cabling ie green/yellow.

A Tip is that after dismantling the original TX secondry windings and reassembled the laminations it is possible to feed and wrap the new wire round the former, this makes it easy to experiment with different turns and you can get more on.

Hopefully some pictures will now appear!

Dear Michael,

Thanks for this site info, it is very helpful, I have chosen to use Ni-Chrome 14 Guage wire I assume it is "C" type the supplier did not state, the site that you supplied sugested that there was very little difference. I am making progress with the Sled that will guide the wire, but I am a very slow worker, but I expect that I will get there in the end!

Best regards, Paul.

Paul Here,

I have wound some cable 4 times round this time, I wanted 4mm dia but settled for 3mm dia the 4 mm insulation was too thick and touched the laminations, it gives me one volt off load and 0.95V with the 2mm Ni-Chrome, it cuts just right even with 6" of wire bent into a "U" shape, even leaving it switched on for five minutes the TX does not get warm.

That is the easy bit done, now I must make it into a safe handheld tool, it will also require a sledge to maintain the depth of cut.

Many thanks to you all, each reply to my plea for help helped me to think sideways a bit and understand a lot more, with regards to the temperature I should imagine it is about 400* F because it just melts solder.

Thanks and Bye.

Dear Les,

Thanks for this, I have tested my transformer and the output was 0.4 volts which heated my 2mm Ni-Chrome wire but only stuck to the polystyrene and not cutting it, I then altered my 10 strands by putting half of them in series with the other five , this gave me 0.8 volts which did cut the polystyrene but did stick a bit, I have pulled the TX to bits again and will wind 4 turns of 4mm ish diam wire, your 2.8mm dia wire would probably not suit my 2mm Ni-Chrome wire that I have chosen because of its rigidity and use in a builders envoronment, thanks again and I will report back later.

Paul.

Thanks for this Les, I have re-assembled my transformer, I have used ten 1 mm strands of copper wire, wound flat one and three quarter turns, and I will join the strands at each end forming a flat single wire, I will test another day, I just thought that I would respond to your message, The Windsreen wiper Stainles steel was a brilliant idea, I could even of used it to make the secondry winding, if my ten strands do not work I may do that.

I will give a up-date after testing. ( but Wednesday is Housework day and that must come first ! ).

Paul.

I have been doing some testing using my Arc Welder as suggested and a "H" frame. I started with a 2mm copper wire of 150mm length with The Welder set at 30Amps, result it would stick to the polystyrene but not cut, I increased to 50 Amps and it cut slowly but still sticking a bit. I then tried 60 Amps and that was just right the Voltage at 60 Amps was 0.23 volts.

I then tried 2mm Brazing rod 150mm length, it cut sticky at 30 Amps and cut right at 50 Amps and Voltage 0.24 Volts.

I then tried a steel Bicycle spoke of 2.5mm 150mm length. it cut right at 30 Amps (my lowest available setting) and the Voltage was 1.3 Volts.

I then tried 2mm NiChrome wire 150mm length, it cut possibly too well at 30 Amps the Voltage was 1.7 Volts and after several seconds started glowing red!

I have been modifying a Transformer from a 4 Amp 12 Volt battery charger,I had ealier tried to remove the laminations from a larger Transformer but they were stuck too fast and I turned to the Battery charger. I have removed the laminations and the secondry coil and intend to wind 2 turns of a heavy guage wire to it. as demonstrated on a web site, I am trying to obtain some fiberglass sleeving. I thought I must make some sort of report back before you all loose interest, I will report on my final result when finished.

Thank you all again for your help.

Paul.

I will be having a house extension that will be built with ICF Insulated Concrete Forms, when the electrician wants to run conduit in the 50mm deep polystyrene insulation they use a hot knife cutter that can cut-out U channels of various depths, these cost from £140 to £400 they are of 150 watts to 200 watts AC mains or battery supplies, the blade would have to be 10 guage or more and heat to 600 degrees, I have investigated and found that NiChrome wire of 10 guage will require 23.3 Amps to heat to 600 degrees and if of 6 inches in length will have resistance of 0.03124 Ohms.This to me means a very low voltage is required. The cutters on the market are quite small and I can not see how they can make them so small.

My questions are what metal do they use in the heating cutter, replacements appear to cost £20 to £40. I want to make one that is sturdy enough to survive a building site and not be dangerous.

Many thanks to anyone who may have experience of these.

Paul Sims.

Dear Helpers,

Thanks for the help supplied, this all helped me to understand in my own head what the options were.

I attended the Guildford model engineering society Rally at Stoke Park Guildford, on Sunday and a very nice man on the Home and Workshop Machinery stand looked through his stock of taps and found a 1/4" NPT tappered Tap, how good was that! Therefore I decided to Tap rather than turn the thread in the Lathe, thank you Andrew for your suggestion. Hopper suggested that I buy a Plug/Bung from my local Plumbers merchants, I visited two Trade suppliers and neither could supply a Iron or Steel Plug/Bung, they had Brass ones but these had very little meat in them to Tap a thread, I then sorted through all my plumbing stuff and found a brass Plug/Bung with ten mm of meat.

What drill to use? I found some data suggesting 7/16" for a 1/4" NPT tappered Tap, this I tried but got only one thread into it, I then tried 11.5mm drill and got nearly three threads, I then tried a 12mm drill and this was just right as Goldilocks said to the three bears.

So I ended-up with the Rusty Plug/Bung supplied by my friend Tapped to take the drain tap, plus a Brass one if the rusty one is beyond use.

Will I ever use the lathe to make Tappered threads? well with the suggestions you have all made I probably would!

Many thanks again,

Paul

My friend has given me a iron Bung removed from a liquid holding engine and wants me to tap/cut a thread through it to fit a drain tap, that he has supplied.

The bung has a 3/4" NPT thread 14 TPI (which is very rusty and I will most likely have to make a new one).

The tap has a 1/4" NPT thread 18TPI.

So I want to drill and thread the Bung to fit the Tap.

I have searched the Web and found lots of Data but nothing to explain how to go about cutting these threads in a lathe.

Any help much appreciated.

Paul

Dear Neil,

For the tests when the bar was laying horizontal in the vice I started with 0.1mm cuts then my largest was 0.3mm, the cutter was nearly new and was taking long swarf off, sugesting cutting was good! but even after say six traverses you could still hear contact in both directions. When mounted verticaly in the V blocks i only did several 0.1mm cuts with single passes at each cut.

Paul

Dear All,

I am overwhelmed at the good advice that I have received especially Neil Wyatt for the pre-Load info. I am not a scholar or very experienced engineer and therefore really appreciate the advise that I have received. I will try to Sum-Up my conclusions.

To-day I mounted a 150mm long 25mm square bar in the 4 jaw, (before doing this I draw filed all over to take out any dings etc and faced it, removed it and cleaned off all burrs, I checked it with three of my squares all having the cut-out mentioned earlier and was quite happy with it on all sides. I then mounted my precision 4 inch Pin type Vice accross the table of the mill so that the end of the bar was was facing me and all tapped down, I used a 12mm 4 flute end mill and slowly traversed the bar 6 times forward 6 times return, The vertical error was the same as when the Vice was conventionaly mounted, I then repeated with a half inch 4 flute endmill (i know it is only 0.7 mm larger but it was a much sturdier looking tool and things improved.

This Vice which is new has a vertical V niche in the Vertical and Horizontal direction in the moving jaw, I mounted the bar vertically and milled using the half inch endmill with just one pass for each of the three widths required,

The squareness was comparable with the 4 jaw result with the usual slight wavy ness caused by the cutter, I then used a V block in the vice and obtained the same result, I then mounted direct to the Table my Keats angle plate that incorporates a V block and again ended with a square end.

I conclude that MY errors are probably due to Flexing of the End-mill and possibly play in quill and associated parts ( I did always keep the quill barely extended from the head) if I should attempt to face the end of a largish bar in the mill in future then I should use say a 20mm endmill and make many many many passes, (one of my next purchases will be a 20 mm End-mill), or use one of the V-block ways, or stick to the 4 jaw.

Many thanks again

Paul

Dear Mick Henshall,

Thanks for the above. I have spent a couple of hours to-day checking the mill and found all tests well within the limits I have found on the Internet, it really is a very accurate machine I have also Squared off in the four jaw a a square piece of 25mm bright steel about 130 mm long ( I will accurately measure this before testing) then I will try all the ways suggested above, I also have a Keats Adj Angle Plate that incorporates a V Block that I will mount on the table.

Best regards

Paul

Many thanks for your further feedback, It will probably be a few days before I will be able to exhaust all your suggestions and reply as to my results.

Further history: When I had the problem with the Warco, I did not find a reason and was never happy with the results, so I continued to use the lathe, but when I changed to the X3 I thought I would try again but with no improvement, I used the same procedure suggested by Neil, I am not sure what the PRE-LOAD is that Neil mentioned.

I suppose I am lazy and find that protecting the job from jaw marks and then trying to measure the job in situe I am never confident of the resultant measurement My Chuck and spindle would have no problem accomodating said job.

My Vice is the largest of the Arc Euro precision type and is new and unmarked.

Thanks again,

Paul

Dear all that replied to my plea for help, many thanks and you have given me things to check out, I have trammed the vice and mill in X and Y directions and no errors found, I was /am using a RC32 Collet chuck with a 4 flute 12mm endmill, I will first turn the vice 90 dgrees and try in the X direction, I do have a face cutter with carbide tips that might cut on the side, but I have never thought of using it in that way, I could stick with the four jaw in the lathe but measuring the stock whilst in situe I find difficult, OOps another problem!

Many thanks again

Paul.

I have difficulty, no failure, in attempting to square off the end of say a 100mm x 20mm x 20mm in the precision vice in my Arc Euro trade Super X3 mill, I mount the bar horizontaly in the vice and then using the side of an endmill and the Y feed make many passes but the cut is never vertical, I had the sames trouble with my previous mill a Warco GH universal, I do not like using the Four Jaw in the Lathe due to the intermittant cutting forces.

Any Ideas anyone

Paul

Many thanks to you all for your feedback, I have been inspired to make my own.

Thanks again,

Paul

I have purchased a new Sieg Super X3 Mill, and will soon want to add a power drive to the table, Arc Euro say it can be done but will not reccomend any manufacturer, the American wesites list them, but I want to buy in this Country, My question is does anyone know of a UK supplier of a suitable power Feed.

Many thanks in anticipation, Paul