Member postings for Dinosaur Engineer

2016 version still has the archaic out of date ACAD type command line format . If you have a 64 bit hard drive then the Solid Edge 2D package is much more user friendly.

Model/Workshop engineering ?

Edited By Dinosaur Engineer on 08/06/2016 10:55:01

Edited By Dinosaur Engineer on 08/06/2016 10:55:44

When cutting very course threads it is sometimes better to drive the leadscrew rather than the spindle.A leadscrew handle may be used for this purpose.

It's a sign of the times that quality HSS ( USA/ British) is often cheaper in the larger sizes than the small sizes. Most Industry now uses inserted tools and the larger HSS tool sections can be had at bargain prices.

Rebar steel "quality" can depend on the correct hot forming temperatures and hot forming reductions as well as the steel composition. The steel in service should never exceed the proof stress and a suitable high safety factor should be applied. There are many other factors involved and I wonder if all these factors are suitably applied at the design stage and are adequately monitored in the building stage.

One accident can wipe out all the cost saving of inferior cheap steel but we can't expect Politicians to understand that can we ? To allow accountants to make decisions on steel quality is the ultimate folly.

+ 1 to Lambton's comments..

A 3/8" boring in a 0.86" hole seems a little on the small side. The "stiffness" of a bar is proportional to D to 4 power. i.e. a 0.75" dia bar would be twice as big as a 3/8" dia bar and 16 times "stiffer" ( 2 to the 4th power). Thus it would have made sense to change the boring bar to a much larger one before getter too close to the finished size.

I agree that if you can get them solid carbide slips are much better than steel ones provided that you do not drop them or abuse them as they can chip a lot easier. The carbide slips last much longer than steel ones and take a better lapped finish. It's not long ago that a set of grade 1 or 2 slips cost over £1000.

I'm surprised that the method of "boxing in " the hole positions with a height gauge hasn't been mentioned. This entails the marking out with a height gauge ( with a sharp scriber) on a surface plate. The hole position is marked out with a square "box" around the central position . A plate with the required hole size is then positioned over the "box" so that that the mid point of each "box" sides can just be seen and the hole plate adjusted so that the hole plate hole is accurately positioned over the "box" and clamped into position with toolmakers clamps. The hole may then be drilled thro' the hole . The hole plate should be of sufficient thickness to guide the drill before the drill point contacts the plate to be drilled and ideally should have the hole reamed. Also the hole plate should have burrs ( no chamfers) removed on it's underside and may be hardened ( & ground on underside) if it likely to be used a large number of times. This was a common method of marking out holes used in the days of "yore" when access to milling machines/jig borers/ lathe was limited (and before DROs were invented !) & only drilling M/Cs were available. Most of the old toolmakers had a number of hardened drill plates for this purpose & in addition a set of toolmakers "buttons" for use in the lathe or drill press. With practice "hole boxing" would give hole positions within 0.003" & was quicker than the more accurate use of toolmakers buttons.

Edited By Dinosaur Engineer on 17/02/2016 22:37:56

Late Students are D1-4

The method will work with ordinary cloth but works better with fine to meduim emery cloth.

Edited By Dinosaur Engineer on 14/01/2016 15:44:52

This "trick" is as old as the hills. I was taught this by an old toolmaker in the mid 50's ! The emery cloth puts a small chamfer on the edge of the hole before the drill starts cutting and it stops the drill from biting too quickly. Also the cloth supports the drill between the 2 cutting points and minimises the drill wandering from the proper circular path. 3 flute drills are much better at drilling thin material as the drill is supported by 3 points and not 2. The method shown does result in a hole slightly bigger than the drill because of the extra material taken out by the emery. Clamping some thicker scrap material on top of the thin material to be drilled will give the drill better support and minimise any "wandering" by the drill and gives better hole dia. control..

Just an update for information purposes :-

The Hofmann UTH spindle has a 7deg 7min 30sec taper with 36h6 register dia at the chuck mounting face. This is the same angle that is used on camloc spindles but of course the dia is much smaller. Also has a M.T. #3 in the spindle bore.

Haven't seen MEW 237, but if the backplate holes are to be clearance on the screws then the old timers solution was to very lightly smear a very then coating of grease where the holes would approximately be and then sprinkle some chalk dust down the chuck holes and fit the backplate over the chuck. The assembly would then be turned over and given a sharp rap with a mallet/lead hammer. Upon separation the hole positions would be clearly shown with chalk circles. It is surprising how accurate this process is as the center-punching of the chalk circles by eye is quite easy . Ultimate precision is not required as the chuck should only be located by the backplate register and not the holes. The old timers didn't waste time in making precision holes where non was needed & making transfer punches but just got on with job.

Edited By Dinosaur Engineer on 08/01/2016 17:50:09

My inkjet printer runs on ASDA DIY refill inks . The cost works out at less than £2 total for a complete 5 cartridge refill. I can get more than 2 complete refills out of the £4 ASDA kit. The print quality is not quite as good as the Canon cartridges but is perfectly acceptable for non-photo use. I shall hang on to this printer for as long as I can as the later printers detect the non-propriety inks and refuse to work with them..

"Way back when" I did a 5 year mechanical engineering apprenticeship in a Co. that did lots of large iron casting machining . Without exception all the guys in the M/C shop ( millers , planers, vertical turning M/Cs, turners etc.) never wore any sort of gloves. Their hands, arms and faces showed extensive black C.I. ingrained dust that would not wash off despite using carbolic soap and vigorous scrubbing with brushes. Barrier creams were unheard of then. Despite this, none of the machinists had any visible hand injuries. On reflection I think this was due to the non-wearing of hand gloves.

As training mechanical engineers, we were given a very thorough training with 9 months full time at a local technical coll.and were expected to reach HND/HNC standard thro' day and evening courses We served about 6 months in each dept. and had many tales to tell ! Happy days!

Edited By Dinosaur Engineer on 06/01/2016 16:40:49

I too have the same problem as Pete (SPURY) reading rules with 1/2 mm markings. I find the same thing with 100ths & 1/64 ths. The length of the line engraving does have a bearing on this . The shorter length markings seem to be easier to read. Surely rule manufactures are aware of this problem ??

Eureka !! I have just discovered that my division plate is indeed double sided . Without this forum I would have never known this ! The latest instruction does not say where to fill the worm/wheel cavity with oil . I'll have to investigate this , maybe access is gained by removing some screw or stud fastening. Maybe there is a filling point on the underside of the pivoting section ?  My head spindle clamping is not hydraulic and is the same as Steve's. Seems only the later heads have hydraulic spindle clamping. Many thanks to all concerned re. the double sided plate.

Edited By Dinosaur Engineer on 18/12/2015 19:06:52

I,ve just received Hofmann's latest UTH dividing head operating instructions and as J.S. mentions, spindle clamping oil is specified as BP HLP 5. This is a pre ISO std. spec. but any hydraulic 32 viscosity would be suitable which is cheaply available ( about £5 per L). My head is the small non differential geared type similar to Steve's. This latest op.instruction is slightly different to my old head but the essentials are the same. Does anyone know what spec is the outside spindle taper fitting for chuck mounting ? I intend to make new chuck back plates. Seems that very early heads,the spindle lock was done by clamp ring and not by hydraulics.

These heads were only supplied as std. with 1 division plate (13-49 holes) with the 2nd plate, (51-99 holes), as optional extra. The std plate covers all divisions up to 50 and many above with the 2nd plate covering all divisions up to 100 and many above this.

I can well understand that a lifting eye is a desirable feature as even the small head is heavy, but at the expense of no spindle lock ?!! Maybe spindle locking on J.S.'s head is done by turning the eye bolt ?

Happy days .

.

Edited By Dinosaur Engineer on 16/12/2015 16:58:05

Edited By Dinosaur Engineer on 16/12/2015 17:00:01