Member postings for old mart

To spread the load on the dovetail groove in the cross slide, I decided to use four bolts with longer bases than standard. For strength, they are one piece. They were as much bother to make as the rest of the repair put together. Not only are they dovetail, but they are also curved to match the circular groove. A friend of the museum made a custom tapered end mill on his cutter grinder. The rotary table played an important part making them, but I forget exactly how I did them. The picture looks like one of the old ones. The thickness of the bolted on repair can sometimes obstruct the tailstock.

Edited By old mart on 29/12/2019 19:45:06

Edited By old mart on 29/12/2019 19:49:01

I looked in Groups I O and found nothing.

I found this crack in the cross slide of the museum's Smart & Brown Model A, a few years ago. The crack is still there, but reinforced by a milled steel bolted on addition.

The Model A at the museum is certainly not a museum piece, All the modifications and repairs use metric threads as they are easier to get hold of. The only exception is a 3/8 BSF helicoil in the apron where only about 50% of the original thread was left. I even drilled a couple of 8mm jacking screw holes in the saddle as it was a pain to get the apron separated as the dowels are tight. The repairs to the cracked cross slide use 8 and 3mm threads. If I can find the photos for that repair, I will start a new thread on the subject. 

That pic of the screws reminds me of when I was a kid and broke a banjo bolt in the rocker oil feeds of my R E Constellation. It was miles from home in Kent. I took the broken bits to a local garage and the mechanic made me a new one in five minutes by just filing a flat on a bolt, easy when you have a practical mind.

Edited By old mart on 29/12/2019 13:43:49

Edited By old mart on 29/12/2019 13:49:47

Another reason for my buying a Schneider ATV 12 was the wattage lost to heat at maximum output. The unit is 0.75 kW and runs a 1 hp motor. The waste heat is equivalent to 44 watts which is as good, or better than the competition, the efficiency, hopefully, being the result of design and quality components.

It's such a shame that the Yahoo groups have just died a death, I would have put the question directly to them. I think it would be a good thing for everyone who has never seen a S & B lathe except in pictures to stop clouding the issue, and refrain from stirring things up. I'm surprised that nobody suggested metric threads, they made metric models.

Best wishes everybody, even the motorway signs on the M4 in Wales had seasons greetings on them.

I bought a Schneider 0.75 Kw for a 1 hp motor to power the R8 modified Tom Senior light vertical which we have at the museum. I chose it from the Inverter Drive Supermarket primarily because they publish a quick start guide for some of the inverters they sell. This makes wiring for remote control and programming a doddle. The quick start guide makes the extra outlay worth every penny. You won't need to be among the stream of people crying out for help when they run into problems with their cut price kit. 

https://inverterdrive.com/group/AC-Inverter-Drives-230V/Schneider-ATV12H075M2/

Edited By old mart on 25/12/2019 19:56:29

I have a recent copy of Linux Ubuntu and found it is quite easy to get on with, a lot of similarities with the Windows controls. The advantage is that it is free and more secure than most.

They came today, SGS brand, dangerously sharp on sides and ends with what looks like TIALN coating. The look like they are down about 0.1mm on original size, not that I could care less, not having a CNC mill.

That application will be better with a rough surface finish, the grip is better.

I think Duncan is probably right about the 2BA, it is much more likely to be used than 3/16 BSF, and pretty close in size. The model A has 2 and 4 BA, 1/4, 5/16 and 3/8 BSF threads in steel and cast iron. I don't remember if the headstock is held on to the bed with 3/8 or 1/2 SHCS.

Edited By old mart on 24/12/2019 14:29:31

A little oil in the holes in the wood will soak in and prevent the rusting. The tapers should be wiped with a clean rag or tissue before fitting them each time and never assume they are clean, however they are stored. 

We are in the fortunate position to have inherited a MT2 reamer at the museum, so producing the holes would not be hard for us. If the final bit of reaming was done by hand, the hole would end up bellmouthed and the tooling would be less likely to jam in place.

Edited By old mart on 24/12/2019 14:13:23

Welcome, Mitch, whatever question you have, there will be plenty of answers here, so keep them coming. The lathes UK website have lots of information of Myford and also sell manuals if you don't have one already. And thanks, Rockingdodge, for that useful website, which has been added to my favourites.

**LINK**

Edited By old mart on 24/12/2019 13:58:23

You would be best to turn the soft centre to get the alignment done, but putting a dead centre in the spindle taper and repeating the tests would be an excellent check of consistency. The freshly turned soft taper absolutely guarantees alignment with the spindle axis, until you remove of course. I keep the shank of a bolt for exactly this purpose, and reskim the taper before testing. When I bought the test bar, I made the mistake of using a live centre in the tailstock, and what I got was the runout of the centre. changing to a dead centre, and turning the test bar in it proved that the centre in the bar was good, I got zero detectable runout. The test bar in the advert is cheap enough and has the added advantage of having the Morse taper built in. It can also be used in the mill spindle and in the appropriate size collet for testing and alignment.

I have three lever type that get used regularly for checking runout, it doesn't matter what they read in that context. I also have plunger dti's which are intended for exact measurement, especially in conjunction with surface tables, they only get used once in a blue moon. They are intended to be used with the plunger vertical, horizontal use can occasionally cause errors because of friction being greater than the return spring strength.

I never expected such a long link, still, it works.

You will find an alignment bar to be of great usefulness. I have two of these with a MT2 one end and centres each end, one about 7" and the other 11" long. To check the tailstock, it can be used in two stages.

1 put a piece of 3/8" stock in the chuck projecting about 1/2" and turn a 60 degree taper on the end. Do not remove it from the chuck. Then put the test bar between the centre you have just produced and a DEAD centre in the tailstock. Mount a dti on the saddle and run it along the side of the bar to check the tailstock alignment. Adjust as required. Then run the dti along the top of the bar to check the height of the tailstock relative to the headstock.

2 fit the MT end of the bar in the tailstock, then you can check if the quill is in line. Try this over the full stroke of the quill.

As you have proved that the error is not with the headstock, most of the error will be in the tailstock, and if the bed was twisted, it would show up when you turned the 1" X 8" bar. 

https://www.ebay.co.uk/itm/2MT-Lathe-Alignment-Test-Bar-MT2-Alloy-Steel-Over-All-Length-283mm-11-1-8-Inch/174007649507?epid=19028343798&_trkparms=ispr%3D1&hash=item2883aa04e3:g:5vUAAOSwxBNcypvK&enc=AQAEAAACUBPxNw%2BVj6nta7CKEs3N0qULvMK1kOsJidtOIv6tvoFynHVpYAhNT3AO6m1jdy3yT6ga38eVq60l7SkJV3oAAhGC4p6bxn5N13yisHN7T%2FmhH08Ka4nZOK7nkZSqP9u1%2BPQ5EDPMjW4i1Lw0gLkB8s7oltqacLqMWcjuTqswwi2fceN3%2BuwiVXKGHyTPMYOZFZpn3%2BsIGRYVlwGzj8jgT%2FD%2Fhk4cD0wqthCN5PQ%2FhPPrM%2B0NSlCwhYZSdCbgTS62tgeq7srEeBukvIFsc73AfVBqhLtB%2BTWLTE1Exz9ogURD6K0dslLDct6qUf8FbPxyqanh1FGAoTL%2BJbK8kcMIWqdxVNRkPgqtBtjHbItmmCInuXJWTj%2Bjvg5L%2FHrxyzUJ35%2Fnq%2FOFeLF2QqTn%2F7g6Nwnbp1RQlUZiImzAc0PsMI13PQE%2F70xj%2F3urN9QcMu%2FSoHPH%2FLpFCpMa%2FmvOfnybmF9cyUpck1XGtlcNmIh6ik%2F7BFoyYHWOfO%2BMY62ZDL0%2FLSTWMTQiB0tKCb9bHzPa5q0AfpkkjZCjb%2BTEyltIpsbPItkv0xKASwasuwiJkWD1niHk3sia7p5A%2Bks3Z8omYcysh89rlDPHrhWRMEhZu2mevKMqKh2v7%2FFt1duVh6D9hcwu%2FRxMR%2ByX%2F2KekEBYA5xc0X54q2wGPJ%2BsxmiSlDrs4D17WNIBUyxnfGtqPKFdS956qg3p9KaGGo845%2FaPxxm3lIV7t0x0dD08Z09MS1Q3y%2BJyCNN%2B9uoORuWasywoQ4Yzuk%2FYwlxvx4QSvzNn%2Fkc%3D&checksum=17400764950763df7ac517714bffa2fafc72247dacd5&enc=AQAEAAACUBPxNw%2BVj6nta7CKEs3N0qULvMK1kOsJidtOIv6tvoFynHVpYAhNT3AO6m1jdy3yT6ga38eVq60l7SkJV3oAAhGC4p6bxn5N13yisHN7T%2FmhH08Ka4nZOK7nkZSqP9u1%2BPQ5EDPMjW4i1Lw0gLkB8s7oltqacLqMWcjuTqswwi2fceN3%2BuwiVXKGHyTPMYOZFZpn3%2BsIGRYVlwGzj8jgT%2FD%2Fhk4cD0wqthCN5PQ%2FhPPrM%2B0NSlCwhYZSdCbgTS62tgeq7srEeBukvIFsc73AfVBqhLtB%2BTWLTE1Exz9ogURD6K0dslLDct6qUf8FbPxyqanh1FGAoTL%2BJbK8kcMIWqdxVNRkPgqtBtjHbItmmCInuXJWTj%2Bjvg5L%2FHrxyzUJ35%2Fnq%2FOFeLF2QqTn%2F7g6Nwnbp1RQlUZiImzAc0PsMI13PQE%2F70xj%2F3urN9QcMu%2FSoHPH%2FLpFCpMa%2FmvOfnybmF9cyUpck1XGtlcNmIh6ik%2F7BFoyYHWOfO%2BMY62ZDL0%2FLSTWMTQiB0tKCb9bHzPa5q0AfpkkjZCjb%2BTEyltIpsbPItkv0xKASwasuwiJkWD1niHk3sia7p5A%2Bks3Z8omYcysh89rlDPHrhWRMEhZu2mevKMqKh2v7%2FFt1duVh6D9hcwu%2FRxMR%2ByX%2F2KekEBYA5xc0X54q2wGPJ%2BsxmiSlDrs4D17WNIBUyxnfGtqPKFdS956qg3p9KaGGo845%2FaPxxm3lIV7t0x0dD08Z09MS1Q3y%2BJyCNN%2B9uoORuWasywoQ4Yzuk%2FYwlxvx4QSvzNn%2Fkc%3D&checksum=17400764950763df7ac517714bffa2fafc72247dacd5

Edited By old mart on 23/12/2019 17:20:31

You try actually checking the difference between 38 and 38.5 tpi, I would not be able to without a shadowgraph.

4ba and 3/16 BSF repair coil kits are easily available as long as there is enough wall thickness around the hole for the oversize tapping. 

When measuring the od of a male thread, it is always smaller than the theoretical size.

Edited By old mart on 23/12/2019 16:53:00

You have 3/16 BSF screws if they measure 0.1825 and have 32tpi. And the 4BA looks good, too. Check out these thread charts from Motalia, they can be printed out;

**LINK**