Member postings for old mart

An impressive undertaking, DG, you must be very proud. And correct in preempting any comments about the chuck key.

I would sell it and put the proceeds towards a chuck more suited to your lathe. ARC have a range and backplates for Myford.

Regular draining may or may not help with internal corrosion, but always helps with reducing the water in the lines which can make spray painting difficult. The compressor at the museum is in a lean to outside the building, and to make the job of draining the reciever easy without getting too technical, I removed the drain cock and connected a length of hose. The hose passes through the wall to an inline valve on the wall and then back out to discharge on the ground. Being easy to reach, the water is drained each time the compressor is shut down. Otherwise somebody would have to go outside, unlock the compressor house door and reach underneath to drain it. I don't see that happening very often. Funny how these threads bounce back and forth across the pond.

Don't forget, when you bore the taper in the chuck, be sure to set the tool height exactly on the centre line.

I always recommend the inverter drive supermarket for VFD's as they have their own "quick start guides" for many of their products. This link is for the one that I bought to run a 1hp motor. The prices get higher as the power requirement gets higher. The quick start guides can be printed out and make the programming and wiring very easy. So many people end up in great difficulties when they cannot understand the instructions that come with many VFD's. You would have to check your motor plate for its horsepower, (1hp is approximately 760W), and whether it can be run in delta to suit the common type of VFD.

**LINK**

Edited By old mart on 23/01/2021 15:41:33

We have one of the base castings at the museum, I had an idea what it was, but have never seen the whole thing. Our one has a tee slot rather than a vee. To make ours more useful, I milled the rads at the base square so it could be clamped down to the mill bed. I also drilled three holes through the slot to use bolts to hold it down. We already have some tee nuts which fit, I cannot remember what size they are.

I hope I would not be tempted to publish a photo like that. It would have not taken much time to pack out the clamps so the serrations were in use.

Be aware that reputable makes have a date stamped in the metal boss. This is the expiry date for the discs, there are plenty on sale which are out of date. One of the volunteers at the museum brought this to my attention and I ended up destroying most of the supply of 4 1/2" and 7" discs.

I would be very surprised if there was any damage to the spindle. A chuck using a backplate is preferable to a direct fitting chuck. This is because you can fit the backplate on its own and skim the front perfectly true before fitting the chuck. A Myford spindle is a very strong design and you would have to hit it with a sledgehammer to cause any bad damage.

The 6 and 3mm collets came from ebay, they look alright and the bores are ground and they were very cheap.

I got one of the bearing type er25 nuts from Rotagrip and it is very nice to use.

That steel will be perfectly good for hobby use, get a nut and use it for gauging the thread. The nut would not be easy to make due to the eccentric collet holder. There are plenty of drawings on line for the er range of holders.

I bought one of the Silverline extended nose air die grinders and have been very pleased with it. I believe the extended shank is 3/4" diameter, just a little bit bigger than the chuck at the end. It comes with 1/4" ans 1/8" collets and I have just got 6mm and 3mm collets through the post today.

The spindle bearings in the S head, which is probably the same mechanically are 1" x 2" x 0.591", top and bottom. Code number 07100s/07210x taper roller. The split nut which adjusts the spindle bearings has a left hand thread.The nut is locked by a SHCS reachable through a hole near the top of the quill.

That 500w/ mile could be per mph, then 500 X 60 = 30000w. That would be 30Kw at 60 mph.

pgk pgk's Tesla at 70mph in ideal conditions would require 21000w, about 28hp at the wheels. The car should be pretty aerodynamic and the figures are feasible.

Edited By old mart on 19/01/2021 17:21:07

Edited By old mart on 19/01/2021 17:21:34

Seconds of arc may be beyond the capabilities of your table, my 6" Soba only goes to the nearest minute.

Although you will be using a 16mm bar for a depth of 90mm, plus a bit more probably for clearance, the forces on the bar will be minimised with small depth of cuts and the soft material. The inserts for aluminium are very sharp, allowing depths of cut easily down to 0.012mm, 0.0005". Take your time and you may find it safer to do the boring away from the chuck. If you have a stop for the saddle, use it.

Nice result. There are a couple of things to consider when doing a mod like this. The stainless steel can catch you out when drilling and tapping, it is prone to workhardening. I would recommend sharp drills, slow rpm and good feed rate to minimise the danger. Make any holes to be tapped on the loose side, not tight. With a self extracting quill taper, make sure there is going to be a conflict when clamping on a bracket to the end.

I had trouble drilling one of these hardened stainless readouts and had no option but to resort to a solid carbide drill to finish the hole.

A lot of people get by without the tennons and just use a dti to get the jaws parallel each time.

If you bolt down a block or straight piece of material to the bed aligned with the X. axis, you can fit the vise inverted and skim the tennons. After skimming, and removing the vise, it is advisable to recheck the alignment of the block just in case it has moved. I would only skim the rear face of the tennons as it is easier to push the vise away from you when tightening the tee bolts.

Any stainless steel will rust if the conditions are right, it is the chromium oxide on the surface that helps to reduce corrosion. Look up passivating of stainless steel, its only a google away.