Member postings for old mart

Tom Senior use Whitworth, BSF and BA threads.

I have three boring head tools which take the simple single sided triangular inserts, but they are nowhere near long enough to reach 2 1/2" They use a clamping screw about 5mm size. My smallest inserted tooling is a Garant 6mm solid carbide boring bar for lathes which uses 1.8mm screws.

I would like one of those, I have a hand held Brother label printer, but the USB PC connected type looks much better.

I have a redundant SKY+ box with a 1.5 terrabyte drive in it. The 300 Gb drive out of my older SKY box is in the pc that we have in the workshop at the museum, 30000 hours and still in pristine working order according to Crystal disk info. I dont use spinning hard drives at home any more and SATA SSD's are also old hat now that M2's rule.

Edited By old mart on 05/04/2023 20:41:41

I have been making a mill boring head bar in 1/2" diameter Densimet to use DCMT 07 inserts. It will be long enough to reach 2 1/2". The screws which hold the inserts are also 2.5mm. The threading is the last operation as the hole for the screw has to be offset slightly to hold the insert tightly in its pocket. I used the first tap in the drill chuck part way, but as it is difficult to turn in the Tom Senior, I opted to finish by hand. I managed to break the tap and spent some time drilling the tap remains with 2mm solid carbide drills and endmills. The last part came out with a little persuasion with a micro drift and a toffee hammer. Tomorrow I will be attempting to tap the remaining length of thread. The bar will be the first of several intended to be superior to those aweful brazed carbide things that the heads come with.

I also have milling cutters with APHT 11 which have the smaller size screws which match the insert size and only an ideot would take the same cuts as the APHT 16 inserted cutters are capable of. As Andrew says, the insert is supported and is not totally reliant on the screw.

Thanks, Jason, I was beginning beginning to suspect something like that had happened.

Those photos that I saved from the forum album were totally unusable. They were put in as the lowest resolution that the camera, a Pentax K5D would manage, equivalent to full HD and when I had got them back on the hard disc they were just pixelated rubbish, only 5Kb each, just thumbnails. I don't know how that happened, they look ok in the album.

Edited By old mart on 04/04/2023 19:57:57

Edited By old mart on 04/04/2023 19:58:48

That new Sealey bench could be stiffened with some bolted on diagonal bracing at very little additional cost and effort. If you are concerned about the top strength, then a couple of layers of 19mm thick plywood added would hold a couple of tons. If the existing top can be removed, the plywood could go underneath.

Molybdenum disulfide is good for plain bearings as it chemically changes the surface giving a lower coefficient of friction. This makes the surface layer slightly more brittle which is not a problem with plain bearings, but not so good with rolling contact bearings where the loading is constantly changing.

I have a tin of Comma lithium grease which is 3 or 4 years old which looks exactly the same as when I bought it. In the past, (60's onward) I always bought Castrol LM for motorcycle and car bearings and it always separated fairly rapidly, the layer of oil on top could be easily skimmed off to reach usable grease.

My best boxes for instruments are made from cedar. That wood has better rot proofing than most other woods because of its natural oil content, which may also help when housing steel parts.

If the rpm is critical, then 7075 T6 would be strongest easily available. But the 6082 would be far superior to those ancient Picador cast ones.

I'm surprised that caster oil is still used for anything. We used it back in the 70's cart racing with the 9E4 class and had regular engine failures even with 16:1 ratios. Then in the 80's a whole season was run without any noticable wear using BelRay synthetic oil at 50:1 in a Suzuki 250 scrambler with 40 hp.

Any of the 6---- or 7---- series would do they are much better to machine than the pure stuff.

Riser blocks have two common purposes, to get the height to a comfortable user position, of great value as you get older, and it makes cleaning up the swarf underneath easier. Thats why you might have to make special ones. We raised the 12 x 24 Atlas up on 40 mm thick aluminium at the headstock end so that "leveling" screw adjustment could be used at the tailstock end. At the museum, we lifted the whole 3/4 ton Smart & Brown model A up with the forklift and put a 45mm thick wood frame under the base to ease my old back.

Every one a con, still it will impress the people with lower IQ's.

As already mentioned, MT1 is a very small diameter to hold the larger sizes of er heads, even my little 7 x 12 lathe has MT3, so a plate type to fit on a chuck backplate would be much better. Getting one lined up should only take a couple of minutes with a lever indicator on a magnetic stand.

I use high temperature lithium grease, available from any car parts dealer for wheel bearings. When you pack the bearings, be sure to leave at least 50% air space or the grease will churn as the bearings rotate and get very hot.

Edited By old mart on 02/04/2023 14:13:21

Try googling belt/toothedbelt drive calculator, here is the first one I found, it will probably work for you:

**LINK**

Do they have to be genuine Myford? A couple of metal plates of the same thickness with some fixing holes in them would work, as thick as you like, to get the lathe at a comfortable height.

If you have a choice and it fits, go for the 9", if you ever get something that is marginal for a 7" , you will be kicking yourself. Measure the rad between the spindle centre and the nearest part of the bed, it should be over 4.5" The Smart & Brown model A takes 9" faceplates and the first part of the bed that anything sticking out 1/2" would hit is at the back.

Edited By old mart on 01/04/2023 19:17:19