Member postings for old mart

The prime minister has made some strange comments about care homes recently. The care home that my sister works at as an RGN has kept free of coronavirus so far. The owners of the home used to accept patients from hospital at short notice until the beginning of March. There were tests at that time, but the NHS refused to test prospective transfers to the home before sending them. It seems that the homes owners made the right decision to stop transfers.

Edited By old mart on 10/07/2020 20:10:43

Edited By old mart on 10/07/2020 20:12:03

They have a well deserved reputation for excellence.

To eliminate the possibility of saddle rotation some tests with a DTI could be tried. With a piece of straight metal in the toolpost, get it parallel with the axis of the bed when moving the saddle right to left. Then see if there is any deflection when reversing the direction. With flat ways of Myford design, there is a possibility of rotation which would be less with prismatic ways in other bed types.

To get the best out of a tiny cutter like 2mm, would take about four times the speed your mill is capable of. So you will have to treat them with great care, 0.5mm depth of cut and very slow feeds in steel. HSS must be lubricated in steel and aluminium and carbide in aluminium.

The Tom Senior R8 conversion has room in the spindle bore to accept a self extracting drawbar, which works well, but when I was making the spindle, I put flats on the spindle to make using the drawbar easier. An advantage is not having to strike the loosened drawbar to break the taper.

Another thing to take into consideration is that not all R8 tooling has a 7/16 UNF thread in it. I have a few with 12mm threads, and there is also a MT2 arbor for slitting saw blades which fits into a MT2-R8 adaptor which uses 10mm threads.

I would like to put that video on The home Shop Machinist, but it would get deleted by the moderator instantly. $199 for a Covid 19 test makes you so glad we have a NHS despite its problems.

Having minimum backlash is a huge advantage, and while the mill is in bits, it would be worth seeing if there is room to incorporate backlash adjustment. Also, if fitting DRO's is a likelyhood, then the actual pitch wont matter as you will never be looking at mechanical scales.

No, an 8mm thread is smaller than 10mm. The core diameter is smaller, 8mm is 6.466mm diameter, and the 10mm is 8.16mm diameter.

By the way, welcome to the forum, Paul.

If you are replacing both leadscrews, check to see if they are right and lefthanded. If they are and you want to save money by buying one length of leadscrew, you will have to decide which axis will turn in the opposite direction to before choosing. I fitted a 3mm pitch leadscrew to the Smart & Brown model A at the museum to replace the worn out 8tpi one, and made a dial with 118 divisions on it instead of the original 125. This was because the rest of the lathe was imperial. With both leadscrews on your mill metric, you might just as well go with 120 divisoins, for 0.025mm steps.

If you end up with 4mm pitch screws, then dials with 160 divisions would give the 0.025mm steps.

Edited By old mart on 08/07/2020 13:15:16

As I mentioned earlier, removing the pin should not be considered until you have had much more experiance with the mill. I also said that we have one mill at the museum that has two pins in the spindle bore, and I'm in ne rush to remove them. One advantage of not having pins is being able to use an ISO30 spindle wiper to clean the taper part of the spindle. I did notice the step between the drawbar hole and the upper part of the spindle bore in your mill. I took advantage of that and the space between the end of the tool shank and the step, to make a self extracting drawbar for the TS.

I got a cheap ARC readout for the lathe cross slide and it fitted completely out of sight, but I never managed to get it reliable enough because of the emp when the lathe was switched on and off. Even shielding the cable for the readout was not enough. The type was similar to the scale on a digital caliper which I believe is capacitive.

There are two basic variables, how much is the budget, and how much space do you have?

Welcome Adrian, you will feel at home with the Myford boys being the most prolific lathe users on the forum.

With a tool shank of 12mm, you are limited to 11 ER & NR, and 16 ER & NR laydown inserts. The thread pitches overlap the two sizes of toolholder available to you in both internal and external types. A good source of inserts which are available singly is APT which are very good and not too expensive.

It will get deleted when Neil stops laughing.

Boiling the wheels after soldering would help to remove the corrosive flux.

You could have an excellent timekeeper at that rate.

Some pictures would help.

The bed of the Tom Senior at the museum had milling scars left by some ideot, and I milled the surface down about 1.5mm, and it took months of rubbing on the surface table to get it true again. About 90% of the marks were removed.

Edited By old mart on 07/07/2020 16:26:03

It reminds me of the old AOL promises of a months free trial which was difficult to cancel.

Bet you can't get DT saying that while wearing a mask.

What are the relative coefficients of expension of the common pendulum rods?