Member postings for Dinosaur Engineer

Try holding one end cap in a vice & twisting the other with a close fitting spanner and "wiggling" off. This worked on my Starrett.. FYI The Starrett vial cost was less than £8 incl. postage quite a few years ago

Vials for the Starrett 12" levels can be obtained from Starrett Jedburgh ( spelling ?) Scotland These may fit. The ends of the Vial cylinder are a press fit on my Starrett level. M/W may be the same.. They were easily removed when I fitted a new vial.

As an apprentice in the late 50's we had a competition between ourselves to see who could cut /make the longest piece of lathe swarf. The record was about 30 metres down the isle between the large lathes in the large machine shop.The M/C shop foreman found out and we apprentices were all gathered together and given a very firm warning- dismissal if done again). I suppose it was a stupid thing to do but at the time we thought it was fun. I'm sure that had it been just one guilty apprentice he would haven sacked but firing all the apprentices would have been a step too far.

Happy days !

Edited By Dinosaur Engineer on 31/07/2017 18:00:17

Edited By Dinosaur Engineer on 31/07/2017 18:00:49

"Tri" chrome process is copper, nickel then chrome. Be aware that copper will adhere to rusty surfaces whereas nickel will only adhere to sound clean surfaces.

Reamers (& drills) were commonly supplied with M.T. shanks as the early drill chucks were not that accurate. However as drill chuck accuracy improved ( e.g. Albrecht ) , then it has become quite common to use chucking reamers.. In the 50s & 60s most engineering use reamers and drills were supplied with M.T. shanks to guarantee accuracy . Straight shank drills at that time were primary used for hand drills and drill presses were accuracy was not that important.

Edited By Dinosaur Engineer on 17/06/2017 20:39:57

Short sighted people can see better at close distances than at long distances. Cataract replacement lenses are basically for long distances and don't enhance short distance vision. I've just had a cataract operation on one eye but am now awaiting the op for the other eye. In the meantime am using a 2.5 Dioptre hand lens .I do miss my shorted vision of yesterday year when I could see very clearly at close quarters. Marking out is now a pain ! Hopefully this will resolved after my 2nd cataract op and then can use reading glasses.

Were are the grinding companies that can grind 18" x 12" cast iron surface plates at a reasonable cost ?

"Square" centres were also used on hardened shafts to clean the hardening scaling off the previously centre drilled centres prior to grinding. After the "square" centres had been used, conventional cone centres would be used in the actual grinding operation.

Edited By Dinosaur Engineer on 02/05/2017 18:48:07

Very similar to a "Wolly" (Wohlhaupter - german)

Ah , the smell of hot Castrol R !

The best type of contact breaker had a hole in the middle of the contacts. This prevented a "pip" and hollow from forming in the middle of the contact. Smaller "pips" and hollows formed around the periphery of the contacts and thus the contacts lasted much longer as the pips/hollows followed around the circular path instead of just forming in the middle You couldn't just keep filing the pips down because by this time the "heel" of the cam follower also became severely worn and the dwell angle became compromised..

If you can reduce the weight to equal or less than 1500Kg then a tail lift truck can move your lathe. . If you put it on a pallet and strap it down to the pallet then there are a number of pallet moving companies who will move it for you at a considerable reduction in cost compared to a Hiab lift ( and less likely to get damaged). This is assuming that the lathe can be moved with a pallet truck to the truck tail lift. 2000Kg pallet trucks can be hired reasonably cheaply.

I notice on mecman's post link that Presto states all reamers are now made to H7 tol. What happened to the H6 grade ?

Edited By Dinosaur Engineer on 04/02/2017 19:14:54

Edited By Dinosaur Engineer on 04/02/2017 19:15:25

Edited By Dinosaur Engineer on 04/02/2017 19:15:49

thin part vice.

It all depends on how accurate you want to measure. The 3 point bore mikes are quite accurate but expensive. Telescopic and small ( split ball type) are perfectly accurate for most users not wanting to go to the last "tenth" of a thou. Vernier and electronic calipers suffer from the flats on the the inside jaws not being sharp points and the general accuracy not being as good as a "mike". Slip gauges with the accessory ( rounded ends) are quite accurate but time consuming to use and expensive. For any precision hole requirement it's quite easy to make your own plug gauge ( With steps if you want some warning of approaching the size). The taper pins are quite good for very small holes.

Industrial standard Hardened & ground dowels are meant to be a light drive fit. Dowels are made marginally oversize to achieve this ( a few " tenths" ) . Sliding fit dowels will not give a precise location as there will be some clearance involved. The use of H7 class reamers will also give additional unwanted clearance. H6 reamers should be used. How hard is it to drive the dowels out ? 0.025mm clearance will give quite a loose fit. Knock out holes should be provided. It is better to drive the dowels out rather than have plates becoming canted over and jamming and damaging the holes. Normally H7 holes will give loose dowels. All the old time toolmakers had worn H6 reamers to give a nice drive fit and they guarded these with their lives ! It all depends on your application - you choose ! An old dodge to give a tighter dowel is to tap a ball ( from ball bearing) over the hole - This would be frowned on in professional quarters as repeated dismantling would give a loose dowel and poor location. If the toolroom foreman saw this someone would be in big trouble !

Edited By Dinosaur Engineer on 06/12/2016 00:12:57

Edited By Dinosaur Engineer on 06/12/2016 00:13:23

The stiffness of a round bar is proportional to the 4th power of its diameter. Thus if a bar diameter is increased by a factor of 2 then the stiffness is increased by a factor of 16. ( 2 to the power of 4). This should be born in mind when choosing boring bars as well as indicator bars. But of course the weight of a solid bar also increases proportional to its radius squared. The weight can be reduced by using hollow tubes instead of solid bars.

What happened to the metalwork & eng. drawing classes at schools ? . All the workshop equipt. sold and only now is it realised that that the previous classes were needed. How to solder a resistor or glue a piece of wood/plastic is no basis for basic engineering appreciation/skills. How did we allow this change to take place ? There should have been a major protest from Engrg co.s.

Edited By Dinosaur Engineer on 14/10/2016 03:29:14

If a thin washer is "dished" with a close fitting hole then when the bolt/washer is fitted, the washer flattens and is held capitive.

I've used both for many Years and and much prefer the Solid Edge version . John should try it before making comments. The S.D. version doesn't have Icons but has text boxes to fill in . If a line is drawn in SD the user has a number of helpful boxes such as length , angle , etc ( which move in real time when cursor is moved) to define the parameters of the line- much quicker and easier than typing on a command line.