Member postings for Hopper

If you do want to work out the size, O rings are usually sized by the ID and the thickness of the ring.

So, you can measure the diameter of the groove to get the O ring ID, then measure the diameter of the hole the O-ring goes into and work out the thickness of the O-ring needed to make the difference, plus a little bit for interference/compresssion.

The groove is usually wider than the ring so not a reliable indicator of the ring's thickness.

I have found that some older taps seem to take different sized o-rings from what is supplied in the hardware store kits today and have had to measure them up and go to a good hardware store to buy the o ring by specific size.

It is not really practical to use a screwcutting tool sharpened to a true point. The end of the point invariably breaks off under load. This is one reason (among several) that thread profiles use a small flat or radius in the root.

The depth of thread formulas as given in places such as Machinery's Handbook usually take into account the radius or flat on the end of the screwcutting tool. And the flat on the crest, achieved by turning the OD slightly undersized to make it meet the thread spec.

In practice in the home workshop, a HSS toolbit is usually sharpened to a point at the correct angle and then the tip rounded off by rubbing on a bench oil stone. It may not be the exact radius the standards specify, but as Howard says above, crests and roots are clearance areas with no contact with the other thread so it is not ultra critical. Good carbide inserts of course come correctly proportioned out of the box.

Also in practice on home hobby type machines, you will be hard pressed to achieve exact thread depthing repeatably to a perfect accuracy, due to lack of rigidity in machines etc etc. Even in commercial jobbing shops, the final fit of the thread is mostly done by "try and cut" with a test nut (Or bolt). Relying solely on theoretical depths etc is not considered reliable in reality.

Modern commercial ultra-rigid CNC machine centres are a different story, using precision insert tooling under very controlled conditions. And mass produced commercial threads are deliberately made with much looser clearances than model engineers like to use so that any nut will fit on to any bolt out of the 100,000s made that day or the millions that year. The thread depth could be all over the place within a very large tolerance, but the generous clearance between the male and female threads will allow for it.

So don't make the mistake of mixing up the specified ISO or BS Standard dimensions with the actual mass produced dimensions or even the practical home hobby dimensions.

Edited By Hopper on 25/05/2023 08:55:31

Edited By Hopper on 25/05/2023 08:57:31

Looks like you have done a lovely job. It looks good in the green.

You have the most important guard, the one near your face and left sleeve over the step pulleys. The other one is well out of the way and lots of people run without it. It is handy to be able to grab the (stationary!) large pulley to rotate the chuck when using taps and dies in the lathe. I have thought about removing mine on my ML7 for that reason, having grown used to it on my unguarded old Drummond. But in the end made a spindle crank handle instead, which works even better.

Sheet metal, even thicker variety, is not suitable for weight bearing on shelves. It needs an underlying framework etc to support the weight with the sheet metal on top to form the flat surface.

Framework can be as simple as some pieces of sheet metal bent into angle "iron" and attached to the top to reinforce it. Or it can be heavier angle or square tubing or wood etc.

Supermarket shelves are a good example. They are about the size you need, made from about 1.5mm thick sheet steel. But the sheet steel is bent over into a 25mm square all the way around the edges and there are several reinforcing pieces of sheet-metal-angle spot welded across the shelf on the underside to take the weight in the middle. If you can buy old ones from the scrapyard they make excellent workshop shelves.

The gear on the end of your spindle may possibly be like some Myfords and have a tiny grub screw fitted into a threaded hole drilled and tapped in the very end of the spindle, lengthways, half in the gear and half in the spindle. You have to remove the screw from the very end of the spindle before the gear can be removed. Post a few pics from different angles would be helpful if that does not work.

Someone has done a nice job on grooving the pulleys for Poly V belts. Are you sure the belt needs replacing already? Seems a shame to disturb it all unless absolutely necessary.

Edited By Hopper on 24/05/2023 09:10:17

Thanks Dave. Yes, being blind in one eye and unable to see out of the other, the clearer graduations and numbers are a great bonus for me too.

The MEW article includes details of how I made a spring-loaded indexing detent from a piece of hacksaw blade to engage with the change gears for rapid indexing. And a holder for the number punches that attaches to the vertical slide so it is all lined up and consistent.

Only problem was the el cheapo number punches do not always have the digit evenly or straightly aligned with the square shank of the punch so the zeros came out a little cock-eyed. But you don't notice it in use in the heat of battle. But it might pay to check with a light stamp on a piece of masking tape wrapped around the job before committing to a full hammer blow.

The 3/32" (2.5mm) numbers are much easier to read than Myfords tiny and not "crisp" ones on the old diecast dials.

I am sure you can adapt the simple design to your shaper with no problems. Post some pics when its done.

And an excellent article it is too, if I say so myself .

I made the graduated part of the dial 1.500" diameter. The knurled part was 1.580" diam. This matches the diameter of the original Myford rubbish dial and the fiducial mark it has to line up with. Thread in the hub is 1/4 BSF.

Very simple design of two parts, with simple wave washer in between to provide friction, and a circlip to hold it together. Full drawings are included in the article, along with "words and music" in the latest MEW issue, 328. The same dial fits ML7 cross slide, top slide and vertical milling slide and is easily adapted to any other lathe by varying the thread size in hub or perhaps the OD of the dial to suit your fiducial mark location.

Edited By Hopper on 23/05/2023 11:39:47

Delage, Delarge. What's an "r" between friends?

Unless you are a pirate.

Edited By Hopper on 19/05/2023 11:41:14

Beautiful little machine and even more amazing accessories. Look at that capstan tailstock. Serious bit of kit. Rather odd in having the capstan handle on the back of the tailstock but I am sure they knew what they were doing.

There was a thread on here a while back about the death of Tee Publishing's driving force Chris Deith. I think his family were taking over the business, so there may be some disruption. Perhaps try phoning them. Email inboxes tend to get full and ignored.

Edited By Hopper on 16/05/2023 13:20:41

Haven''t seen the grubscrews but if your lathe has them in place, that is a good way to go.

Some lathes have a threaded collar going into the raising blocks and then long studs that pass through the collars into the the bench. You can adjust the collars on these via their hex heads, after slackening off the top nuts on the studs.

I might add too that the principle shown in Fig 19 above about checking the lathe is not twisted when bolted down, also can apply to when you bolt the feet of the bench to the floor. Any gap there needs to be shimmed rather than the bench pulled down under bolt pressure to close it up.

Edited By Hopper on 16/05/2023 09:41:32

Putting new meaning into a "DIY magazine". Percival Marshall would be proud of you.

Me too. I don't have a mill but for milling in the lathe on the vertical slide and for drilling on my drill press I often use HSS blanks as parallels.The little 1/8" ones are ideal for the tiny Myford milling vice, and can be stacked if needed.

I also often use pieces of key steel as parallels. It comes precision machined to size, square and parallel so ideal. And in a pinch you can drill or mill right through into it as a sacrificial parallel. Available from bearing suppliers. And it comes zinc plated too so never rusts.

And throw it away after 30 years, you will desperately need it for sure after 30 years and 3 days.

No need to spend money on jacking bolts. Shimming works perfectly. And arguably provides a more solid mounting. Cut your shim into a U shape and slide it under the foot around the loosened bolt without removing it.

Bit of info from the ML7 User Manual on how to do a turning test and which foot to shim to bring it into line here. The part about bolting the lathe down without distorting it before attempting to level it or turning test it is well worth noting.

As a rule of thumb on the turning test, if the test piece has taper of 2 thou, I start with a shim of 4 thou under the relevant foot at the tailstock end. The final tiny bit of adjustment can be done by tightening down the relevant bolt without changing the shim. You seem to get a last little bit of movement of the bed that way. You can dial it in dead nuts on this way.

Edited By Hopper on 16/05/2023 09:13:45

The printing press and subsequent machinery to cut, fold, collate and staple the magazine would make an interesting article for MEW. Quite a process to behold, and all happening at a million miles an hour. When things go wrong, they can go really wrong! As has obviously happened. Some printer is about to get his derriere kicked.

Edited By Hopper on 15/05/2023 12:02:42

He does say at about minute 13.00 that if he were making just one part, he would not make the jig. But he says because he has two of the same part to make and he does not feel like messing around with them, he "went overboard" and made the jig.

Even for two parts it is somewhat overboard as he says, but nonetheless a good demonstration of how to make a simple jig that could be used on other harder to hold items.

(Before the purists point out it's a fixture if it does not guide the tool, for some reason in the auto industry they are all referred to as jigs on the shop floor so it is habit for me, even if it is a bad one!. )

As with most jigs/fixtures it looks like making the jig/fixture took much longer than making the part, so definitely overboard. Perhaps Joe is thinking of mass producing the S10?

Edited By Hopper on 15/05/2023 11:45:37

Edited By Hopper on 15/05/2023 11:53:39

I've owned and ridden various bikes with twin leading shoe front brakes over the years and never experienced any failure to work while rolling backwards on a hill etc. And that included a BMW R75/5 and sidecar ridden over some 10,000 foot mountain passes in the Rocky Mountains USA. Pulled over several times on the steeper sections to let faster traffic go by and never had the rig roll backwards or any noticeable problem with the front brake.

Just went out in my shed this morning to double check and my latest Featherbed Norton special with a Norton twin leader front brake cannot be pushed backwards while the brake is applied. Simply will not budge.

Yes, you won't get full braking power out of what becomes a twin-trailing-shoe brake when used in reverse direction, but certainly enough to stop the bike rolling down a hill from a standstill, in my experience. A trailing shoe still has considerable braking power.

Other bikes I have owned with TLS front brake included a '69 BSA 650, a brace of Nortons, a '69 BSA Rocket 3 and a couple of 1971-72 Rocket 3s. Never noticed a problem with any of them re the front brake on reverse slopes either.

Edited By Hopper on 15/05/2023 01:03:26

I would use a butt weld rather than brazing. For critical safety items like that I take it to a professional and get it TIG welded. I don't trust my life to my own bird-droppings welding skills. Recently on shortening a Norton brake pedal for rearsets, the welder at my local light aircraft field did a lovely job of it in return for a few beer tokens.

Thanks. That makes sense.

Less faff that I have been doing with a digital inclinometer on the freshly milled flat. It gets you there but can be fiddly on the small stuff. The bigger hex on the Rose index looks easier.