Member postings for Martin Connelly

We used tapered female threads for gas pipe bosses where I worked. We had to have a suitable thread gauge for them before they were welded onto the pipe as too small or too large would produce a scrap part as the matching male part would either not go in far enough or too far, both were not good outcomes for gas pipes. We used a suitable sealant on assembly.

Martin C

Probably because the original bed design will accept used or after market parts such as fixed steadies.

Martin C

I would want a very well written data sheet for the board to read before I bought it. There are a number of different resolution encoder chips and I would want to make sure it had a fine enough resolution to match the motor and purpose it was to be used for and also that it was compatible with what you have already. If you have a 1.8° (200 PPR) stepper and a 1.4° (64 PPR, 256 edge, 8 bit) encoder chip will that cause problems?

If this is a new problem on an old system then what has changed?

Consider dumping the parallel port if you can. How do you know that this very old piece of technology is still putting out good enough signals to be sure it is not the source of the missed steps. Some of them were a bit close to the acceptable voltage limits even when new. It doesn't take much to interfere with the pulse signals from a parallel port. They were not designed for CNC signals after all. Also if you use these boards then there will be options for detecting lost steps or the magnet falling off the shaft. Do you have enough inputs on a parallel port system to respond to these error signals to stop Mach3 from carrying on as if nothing has gone wrong?

I would be wary of spending money on these boards before checking everything else in the system first. Start with the mechanical setup as suggested by John. Have you got an alternative computer to drive the parallel port for the purposes of checking if that improves the system? Can you decrease the acceleration and top speed of the axes in Mach 3 without causing problems. Could you upgrade to a well proven setup such as a Smooth Stepper? Could you use a gearbox on the stepper output to improve torque at the machine. What about the cost of matched closed loop motors and drivers compared to mixing and matching bits from different manufacturers in the hope they will cure the problem. Lots of things to consider before spending on these boards. I can just imagine having a problem and the board supplier saying speak to the manufacturer and the board manufacturer saying not our board that is the problem, speak to the motor manufacturer. What if one of them says it was not designed to be used the way you are using it? Bit of a minefield that you are going into as you may become the research and development department for other people and we all know they are an expensive part of any group. Have you found anyone else who has gone along this path?

You have mentioned cutting and 3 axes so CNC milling seems a likely use. Are you using climb milling or conventional milling. Conventional requires more torque from the axis motors but requires ball screws for low backlash. Something to consider is that if you use larger diameter tools, tougher material or higher material removal rates than the original machine design was meant for the higher the torque required from the motors. Have you put a larger vice or rotary table on the machine. These increase inertia and friction. Have you changed from sharp HSS or carbide to relatively blunt insert cutters? These increase the required torque from the stepper motors. Have you adjusted the gibs recently and set them too tight? Is there enough lubrication?

Martin C

Howard, you can grind the threads off a short length of the jacking screws as well to push on the bottom of the hole where you have drilled into the chuck.

Martin C

I have a Ø160 chuck that only had outside jaws with it when I bought it used. I found some soft jaws and inside jaws for it on the WWW. I put the inside jaws on the chuck and did a check and there was excessive runout but I knew the scroll and main body were good. I jammed the jaws tight with spacers between the parallel faces between the jaws. I then bored the jaws with a large boring bar and some **GT inserts taking off 0.15mm in 0.05mm steps from just touching the high spot to cleaning off all the marker pen I put on the contact faces. No runout issues now. I have machined HSS with these inserts so I had no worries with using them on hard chuck jaws.

So there is a quick and simple alternative option to grinding the jaw faces if the scroll and chuck body are good but runout is unacceptable.

Martin C

I used to buy in RS Ø3 coated stub drills for the pipe fitters at work to make pilot holes using a hand drill in 316L stainless pipe. Stainless is notorious for finding drills that are worn or sub-standard but the RS ones were dependable. RS probably sourced them from a quality manufacturer but there was nothing to tell you who made them on the drills or generic boxes. The pilot holes were usually for the pilot pin of a mini Rotabroach cutter also used in a hand drill and they were also dependable when cutting holes in the stainless pipe.

Martin C

I don't like any digital callipers, my go to is a 150mm vernier calliper with fine adjustment (one is no name the other is Mitutoyo). Linear tools, for example, do a 145mm one for about £23. I have micrometers for both metric and imperial measurement up to 100mm/4" but find the vernier callipers give the same reading as micrometers. I certainly don't trust the digital ones without absolute readings, it's too easy to accidently set the zero at the wrong point.

Martin C

Click on the black camera icon in the reply window to insert a photo from an album.

Martin C

In the RAF we had two specially bent screwdrivers for the screws on the alternator connector cover. They were straight slotted screws and you could only turn them 90° at a time before swapping to the other screw driver and doing another 90°.

Chopping and modifying spanners/wrenches was a regular occurrence when I was at work. Heating and curving 27mm combination wrenches to fit around pipes for tightening flange nuts was a frequent request of the welders with access to oxy-acetylene. We also made curved tooling to fit on the end of spigotted torque wrenches for similar reasons. We set the torque value for these tools on a calibrated torque meter. There were quite a few half spanners welded at 90° on a long bar to reach where other tools could not go.

I think making and modifying tools is a standard engineering role.

Martin C

I've got a saphora (Sun King) in my garden that is covered in yellow flowers for about 6 weeks from mid march onwards. It attracts lots of bumble bees every year. Later on in summer the very much not yellow hardy fuchsias (Lady's Eardrops?) attract honey bees.

Martin C

I mentioned in a recent post about ending up with 3 monitors on my desk at work to improve workflow, swapping between different programs on one screen is very clunky. Designing a tool/jig in CAD on one with one or two views of a part drawing on the other screens is a common example of where it becomes so useful, even if one screen is a 14" laptop screen.

Martin C

Mike, 3 jaw self centering with freshly bored soft jaws at the required diameter or a Griptru adjustable chuck.

Martin C

Dave, I think you are correct that this is an approach that is based on past technology and cutter material. I think that trying to follow this rule of 5° above centre would result in a lot of tool height setting unless you are only working on a small range of diameters. This makes me think it was aimed at a production line where someone may have had a large batch of one part to work on at a time. It would cause problems if you are trying to work with the dials or with a DRO to achieve a dimension, with CNC or where overall dimensions may change from bar stock size to finished size at one setup as you are only making a one off part (like a lot of us on this forum are likely doing).

Martin C

There are a lot of older screw on chuck standards (so not really standard) that make it unprofitable for a chuck supplier to stock all possible combinations of thread form and tpi/pitch, diameter and length. Separate backplates is the normal situation for most people with an older lathe and one of the things that many people end up doing after buying a new chuck is making a backplate to suit. You can buy chucks that fit directly on to some lathes but they cost a lot more as a result of being for a relatively niche market. One of the advantages of making a backplate is it can be tailored to suit the lathe and chuck it is to be used with for a better final mate up of chuck to lathe.

Due to the demand for chucks that can be fitted without having to make a backplate and the premium put on the Myford name by some people it makes some fiscal sense for the chucks to be sold separately from the lathe when selling a used Myford lathe. I don't think this happens with many other makes of used lathes.

If you had found this site before you spent any money you would have found plenty of people willing to give free advice, sometimes a few contrary views but usually all amicable. In the case of your mill if you had asked about a "round column mill" you will find plenty of information both here and on the WWW. I often suggest people find the equivalent machine supplied by Grizzly in the USA and look at their manuals as they rewrite them for an English speaking customer base and include a lot more detail than the original manufacturer feels it is necessary to supply. A quick internet search for Grizzly round column mill identifies a machine with a manual that can be downloaded here. Grizzly G0705 manual Search YouTube for "round column mill" and you should find plenty of useful videos.

Martin C

Edited By Martin Connelly on 21/04/2023 13:16:24

Drag engraving or vinyl cutting maybe?

Martin C

It is hard to find hard and fast figures for this and it is based on current technology. The break even point for the green credentials of an EV is a far greater mileage than I will do in 15 years since I no longer commute to work 5 days a week. Since it seems likely that the battery will need replacing if it gets wet or damaged in that 15 years the true eco-friendly cross over point of an EV is probably greater than claimed. Estimated lifetime of the batteries is turning out to be optimistic. Insurers are writing off EVs with damaged batteries because they are too costly to replace.

My conclusion is that it makes little sense for a driver doing low annual mileage to be forced to buy and use a vehicle whose production using current technology causes such damage to the planet over and above current ICE vehicles before they have left the showroom. Where I live is poorly catered for by public transport so a car is pretty much essential. I was recently asked to go to for routine check-up at a local hospital 39 miles away.

Back to infrastructure matters, I remember reading that if all cars are driving down the centre of traffic lanes under the control of a self driving vehicle computer then the road will rapidly become rutted as wear is not distributed over the whole area of that lane. I was reminded of this recently when driving in lane 1 of a motorway that had obvious ruts from HGV wheels. Heavy EVs will also add to this damage.

Perhaps we need a small, lightweight, high mpg class of ICE vehicle for people who only do a low annual mileage as an alternative to being pushed into a heavy EV with a high, upfront, carbon footprint.

Martin C

Edited By Martin Connelly on 19/04/2023 08:42:51

Where I worked the drawings were almost all on coated polyester film when I started there (up to A0). These were also photographed/scanned and positive 35mm film images were put into aperture cards for everyday viewing and printing. When networked computers became a normal desk top item the aperture cards were all scanned as tiff images available over the network. As CAD became the normal method of producing designs and drawings the images were saved directly to the network. By the time I retired I had three monitors on my desk. For some work I did I needed one for looking at drawings, one for a spreadsheet and one for the program I was working on to produce my work output. Without three monitors the paperless office was always going to be impossible.

I suspect the future will be all digital.

I still drew up full sized layouts on polyester film (using coloured marker pens) for pipe fabrications but getting the polyester film was getting harder by the time I retired. 1500mm wide film was the first to disappear.

Martin C

Edited By Martin Connelly on 18/04/2023 18:58:16

I do not have the gap in the base of either of my milling vices, so no good for me.

Martin C

RDG sell a range of aluminium V pulleys. Probably other suppliers as well.

Martin C

It was the comment about the really nice finish that made me think ferritic stainless was a possibility. Ferritic stainless is the type often used for cutlery as it is better described as stain resistant but can be produced with a good finish to look nice on a table. the best way to tell it from mild steel is the rate of corrosion on the surface. A polished piece of mild steel will not corrode very fast but if you get some fresh filings off a block of steel and drop them in a bit of warm salty water you will soon tell if it is mild steel or a stain resistant alloy.

Martin C