Member postings for old mart

Good point, MC.

Left hand threads are nicer to produce as you are threading away from the chuck, and that is safer. You have plenty of time to stop things going to the right. A saddle stop would be a great advantage with lefthand threads as your starting point can be fixed.

As you have exhausted all of the possibilities, I think its time to put a soft pad under the quill, and use an aluminium drift to gently tap the end of the spindle. I would measure as you progress to see if the tapping does move it. There is no great danger from the tapping as the quill is being removed to overhaul things, ie, new bearings. When the quill is out, the nuts on the spindle are left hand thread.

I have tee nuts with studding screwed into them specifically for use with vises. The studding is locked into the tee nuts and is just underflush of the bottom of each tee nut. Using studding means that the nut will always tighten down and never hit the end of the thread. The length of studding is made to be lower than any work sitting in the vise.

Remove the plate from the front of the head, 4 small screws.

You should check whether the seat could be modified to accept a similar, but more easily available insert. It would need a small solid carbide endmill.

You have picked a fortunate size of thread to practice on, at least you can easily see what is going on. If you can produce both male and female threads yourself, they can be whatever you like. When I modified a Tom Senior mill spindle to change it from MT2 to R8, using a bottom half from Arc Eurotrade and the original top half from the mill, I screwed them together with a thread that was no particular size, but the dimensions were worked out from the thread depth according to the pitch selected.

The tapered pulley hub does not affect the removal of the spindle/quill assembly. The drill mill I worked on has never had the pully hub removed. You did not mention whether you had pushed the quill up as far as it would go to inspect the end of the spindle. The splines should run right to the end without any circlips, or screwed on parts, such as might be required for a captive drawbar. The drawbar should be removed before dropping the quill.

Hopefully, the cutters you have will have their sizes marked on them. The metric ones require the metric collets and the inch/fraction ones, the inch size collets. The same rule applies to the Osborn Titanic type of collets.

There are many proprietry sizes and shapes of insert which will only fit that manufacturers toolholders.

Push the quill up as far as it will go, and examine the top of the spindle to see if there is anything stopping the splines from passing through the drive that the pulleys were on.

This link to a Grizzly manual might help, these drill mills are of very similar design.

**LINK**

Your photo shows the depth stop still in place, have you removed the adjuster screws? Also, the fine feed for the Zaxis is still in place (2 socket head cap screws), I removed that on a similar mill, although that may be clutching at straws. Removing the pulleys would, as far as I remember, have no affect, as the centre part with the female splines would still be in place.Your spindle is empty, I presume?

Edited By old mart on 04/08/2021 21:37:24

You didn't mention the depth stop, but it's so obvious that it would be a very long shot. The other thing would be to use a mirror to look down at the top of the front pulley to see the splined end of the spindle which should pass through the centre of the splines in the pulley as the quill is lowered. A captive drawbar would certainly stop that happening.

Good result, and lucky to be able to get hold of a tap.

This picture shows the front of the museum's drill mill. If the depth stop mechanism and the plate behind it are removed, access for the preload of the spindle bearings is available. And also a view of the inside of the quill bore in the head. Your machine may be similar and there is a possibility that you might be able to see something causing the jam. Does it stop dead, or just get tighter and tighter?

The main shortcoming of a 4 jaw scroll chuck is that it requires perfect material to hold, and even if the material is perfect, there is always a large chance that all of the the jaws are not always the same distance from the spindle axis. A three jaw scroll always clamps on the workpiece even if not accurately. The 4 jaw independent takes more time and effort but can hold the work in any position you would desire.

There will be a length of rack gears cut into the side of the quill and if the gears are not cut right to the top of the quill, and the meshing gear is still in place, that would stop the removal.

The only thing that matters is whether the lathe turns metal well enough for your purposes. I doubt whether 5% of lathe owners have ever leveled their lathe.

The difference in the surface finish either side of the step, and cutting off part of the laser etched characters makes me suspect it has been modified for a special job. I think they started life as normal end mills. Having both drill and mill characteristics makes them very versatile for home use.

Edited By old mart on 01/08/2021 15:53:08

I bought one similar to the Axminster one, I forget the name, the spare parts make it better value. A line of oil should be run along the cut line, or the parts will wear quickly. You can rotate the heads and lock them quickly to make the direction of feed easier.