Member postings for Chris Gunn

Jesse and Roy, do not get too depressed, we make the best aero engines in the world, Rolls Royce Jaguar and Bentley cars, export thousands of land rover, range rovers, minis and Toyotas, make a lot of Europe's Ford engines, leaders in Pharmaceuticals, DNA research, make most of the chips for the worlds mobile phones, world class engineering consultants building bridges, tunnels high rise buildings everywhere. yes we have lost a lot of metal bashing industries, but we are working smarter now, not harder. There is a big shortage of young engineers so that is one thing we need to sort out, and being more positive about what we can do well could encourage them.

Chris Gunn

Hamish, it may be a bit late if you have started, but I imagine your Student has a pad and holes for mounting a rear toolpost at the rear of the crosslide like my Bantam does. Maybe these could be utilised to mount a suitable plate and even give you a bit more room.

Chris Gunn

I run my Bantam from a static converter not an inverter, the coolant pump is the original, and has run for 28 years, but not all the time of course. It is always started after the main motor is up and running and switched off before the main motor.

Chris Gunn

Alan, that sounds like a plan, my only comment would be to still use the gear box a little, so that you keep the smaller motor running at a good speed, a) to keep the torque up, and b) to keep the motor cool. If one is working at a lower spindle speed. select a lowish gear and fine tune the speed with the inverter.

Chris Gunn

Bent spanner, If you want my bolt, I can probably find a piece of shim to take up the 6 thou or so on the diameter.

Chris Gunn

Al, Bob answered the original HP question as far as your 3HP motor, if the motor is the right voltage for an inverter, in my opinion it would not hurt to have some extra power, but do not overdo it and overload the machine when turning, as you could break something. The motor may be "free" but you would need a more expensive inverter to run it.

Chris Gunn

The original Bantam motor is a 2 speed motor, 1500 nom rpm in low speed, 3,000 nom rpm in high speed, if your original motor would only take the lathe up to 800rpm, it was probably a 1500 rpm motor, unless the pulleys were changed as well.

Chris Gunn

It seems there is a lot of head realignment going on out there, probably due to the design of the Chinese vertical millers on the market. I recall that when I was doing my apprentiship using a variety of vertical millers, most of these had a vertical head that bolted to the machine column. The turret head as we know it now had not been invented then. The head could only be misaligned in one plane provided it was assembled nice and clean, but to align the head in the vertical position, a taper pin was provided to press into a reamed tapered hole drilled through the bolting flange into the machine column. The head would be fitted, the bolts nipped up, and the pin tapped in before finally tightening the binding screws. This would align the head perfectly in 30 seconds. The taper pin was threaded and a nut and washer fitted so it could be extracted when the head was moved or removed. It is possible that other holes were provided 90 degrees either side of vertical.

I do not have access to one of these millers so can only suggest that if there is space for a taper pin somewhere in the head mounting flange(s), the head should be properly aligned using the device of your choice, then it would not be a big job to drill and ream a standard tapered hole with a 1 in 50 taper reamer, and fit a threaded taper pin to ensure repeatable alignment without the use of any head realigning tool. If the head swivels in 2 planes, 2 pins could be installed. I was able to find a source of ready made threaded metric taper pins made for this purpose, but not imperial ones. I would have thought that this would make a good project for MEW.

Chris Gunn

Michael, when I was working, if I was trammelling, I was drawing a big circle.

Chris Gunn

I know this will not help much but where did the phrase "out of tram" come from, surely the head or spindle is out of alignment or not square or not true?

Chris Gunn

Hi bentspanner, I have just had a rootle in my 1/2" BSW tin and found some bolts to your specification apart from the plain section diameter. All I have miked up come out at 2.5 to 3 thou down on the nominal 1/2" diameter. I would bet this is industry standard. I have some cap screws too, these are even less on the plain part. Could you make a shim steel sleeve to take up the slack, if any? It would be OK for hand operation surely.You are welcome to one, pm me with your details. Chris Gunn

Welcome to the hobby pgk, if I was setting up another workshop with a budget of £6K, I would buy the kit I have now, accumulated over many years of Model engineering.

Lathe, a 3Ph Colchester Bantam with as many accessories as you can get, Say £1,500.

Miller, a 3ph Bridgeport with variable speed head and horizontal spindle attachment, another £1,500, and a 1ph to 3ph Transwave converter to run them both, £500. 3ph machines are cheaper, and using a converter allows all original motors on both machines to be used, e.g. coolant and feed motors.

A Fobco bench drill, say £250, a circular cold saw or a bandsaw to cut up stock, another £250, a linisher and bench grinder, £150, a rotary table for the miller, £200, a couple of milling and drilling vices, £200, a set of used micrometers 0 to 6”, say £100, which comes to £4,650 or thereabouts.

This leaves £1,350 to buy a bench vice, a used surface plate, marking out equipment, other measuring equipment, drills, lathe tools and milling cutters and any other odds and ends. I would buy all good used equipment, and walking into any of the dealers with this sort of prospective order ought to result in a few goodies being thrown in.

If you are unsure then stick to a dealer and pay a bit more but have some where to go with any problems. If something good came up privately, you would need to take some advice on this perhaps. I think it is important to at least have some idea what you want to do, but the above kit is capable of building anything from a small Stuart Turner steam engine to a 5” gauge loco and almost everything for 6” scale traction engine.

I am afraid I do not buy into the “buy as big a lathe as possible as one can do small stuff on a big lathe but not big stuff on a small lathe school”, but if 95% of your work is small stuff, you will be making life harder for yourself for 95% of the time.

Most projects will involve many more “small” components than large ones, and there is always a way to get a larger item dealt with by getting it pre-machined by the supplier or using a large lathe at a friend’s or a local ME club.

The Bridgeport miller is very versatile, and will allow you to mill and drill both small and large parts, with the appropriate work holding equipment.

Good luck with your project.

Chris Gunn

Ray, if you do get to NZ, Motat in Auckland is well worth a visit, lots of stuff there, and close to the port if you go by ship to Auckland. If you cruise, lots of sea days, to see the most of NZ, in my opinion do a land based tour, very friendly helpful folk there, you can do what you like, or maybe a cruise and stay?

Chris Gunn

I wondered about that, but I have several pictures of full size engine springs, and they show no sign at all of holes or pins.

Chris Gunn

Jack, if the machine is single phase that makes life easier, each motor has its own starter built into the base, so you will just select what you need, for example the turret head and the feed motor if you want to engage that, or the coolant. The horizontal spindle has its own starter. I cannot answer the question regarding parts, I never needed any, but one does see used parts offered on this and other web sites. Cutter arbors for horizontal use should be available on the second hand market, it would not be too difficult to make an over arm and support. It is difficult to comment on the suitability of the mill to do what you do now, without having a little more information of what you do in the course of your wood turning.

Chris

Jack, I had one of these for at least 20 years, a very good machine, the turret head means you have plenty of clearance over the bed when using it as a vertical, much more than some other small millers. I had a Tom Senior before the Omnimill, and the Omnimill is a lot better. It is industrial quality too, I guess it may be 3Ph as mine was, so you may need a phase converter to run it so all 4 motors can be run at the same time. The price seems good too, much less than I sold mine for 4 or 5 years ago, check the overarm, all arbors and the steady is with it, and if you are lucky you may have a full set of feed change gears. I only sold mine as I brought a Bridgeport with DRO. Any other questions please ask. The lathe I have had for probably 25 years now is a Bantam, again streets ahead of most of the other lathes that find their way into the home workshop. I have built a lot of models on the Omnimill and the Bantam.

Chris Gunn

John, thanks for that, I must say I am pretty impressed by the collective knowledge on this forum and the speed at which it is dispensed

Chris Gunn

Can anyone identify the casting shown, it is thought to be railwayana, but I am not sure. It has 4" and the number 92 cast in the "front". the base is round, but has no mounting holes.

Chris Gunn

Jason, thanks for that link, needless to say since I wrote that piece I found out that the first 2 6" scale 4CD's were built with cast in spokes, and a few weeks ago saw a 6" Ruston with cast in spokes. I have mentioned the former in a later episode.

Thanks Chris Gunn

Tim, these folk do all types of leadscrews and nuts, you can check out the catalogue.

**LINK**

Chris Gunn