Member postings for old mart

Welding would risk warping and or cracking the bed. If you can clean up the holes, it would be much safer to glue, or screw in plugs which can be carefully brought down level. D G's method is excellent, as long as the holes are not near an edge. You can get a Devcon metal repair putty in cast iron which would match the colour.

Edited By old mart on 06/07/2020 21:33:26

I have bought several of both types of step collets for the museum's model A, including one from this firm, they had two, but they were both the same size.

**LINK**

I had a similar problem when I was using Clarkson Autolock screwed shank cutters. Included were some special Weldon adaptors for 6mm plain shank endmills. These adaptors had a 12mm screwed shank which fitted the Autolock in the normal way. I tried and failed to get 6mm solid carbide endmills into these adaptors. Because the adaptors were case hardened with exactly 6mm holes, the 6mm cutters would not fit. There has to be a certain clearance. I believe the adaptors were intended for use with the 6mm throwaway cutters which were common at the time which must have had shanks in the region of 5.99mm.

I have bought lots of milling cutters and twist drills from cnc poorboy.

Edited By old mart on 06/07/2020 18:40:21

What about the inspector Bonapart series?

You might just be able to reach the scores with your middle finger. How far up do the collets go before getting tight? Normally, when the arbor is almost right in, it should be possible to rotate it a tiny bit which proves the pin is not tight in the milled keyway. Removing the key should not be top of your list of priorities, but an option when you have got used to the mill. A needle file with a safe edge could be used to make the pin narrower, and a 3/4" stick, or bar with a bit of 400 paper stuck on the end with double sided tape could smooth any burrs inside the top of the spindle. Just a few strokes after carefully aligning it would do.

Better than the collets would be an arbor with er 25 or 32 and collets in 6, 8, 10, 12 and 16mm for the commonest sizes of end mills. We have er25, because going above 16mm in end mills gets expensive, especially solid carbide and replaceable insert and shell mills are much better value. The only time that I find collets are useful is if there is a shortage of Z axis height. We have a full set of collets from 2 to 20mm and some imperial ones as well, they rarely get used.

https://www.practicalmachinist.com/vb/general/r8-collet-spindle-internal-construction-question-303406/

Edited By old mart on 05/07/2020 19:21:47

When we got our first mill at the museum, a large drill mill with R8, the spindle had to come out to replace the lower taper roller bearing. Thic particular spindle had two screwed in pins and I kept them, not knowing any better. The mill still has them in the spindle. Some of the bought tooling was reluctant to fit, and I found that the cause was the milled slot was too narrow for the pin diameters. Only widening the slot slightly enabled the tooling to fit easily. When I did the Tom Senior light vertical MT2 TO R8 conversion, I did without the pins. The pins only use is to stop something like a collet from spinning when the drawbar is being tightened and after the taper is broken, but before the drawbar is finally unscrewed. Collets are the most likely to spin as there is nothing to get hold of. To minimise this problem, I have run a 7/16 UNF tap up the tooling and lubricated the threads with moly grease. If the drawbar is free running into the tooling, there is very little likelyhood of having problems with tooling.

Try all your tooling in the spindle, and check whether the tight ones have a narrower slot. Also check the parallel diameter at the top end for variations in size. Use a light and mirror to inspect the inside of the spindle.

Should you decide to remove the pin, then a Dremel would be best to take the pin down flush without dismantling the whole spindle.

Normal lathe design is for the cross slide leadscrew to have a left hand thread. You turn the wheel clockwise to cut deeper.

I think you should ditch the milling attachment, you have a proper mill sitting next to the lathe.

I take it that you have googled Hoover washing machine spares and trawled the hits. I managed to find an old part for a TV from a firm like them.

Nice to know that the bearings can be fine tuned. My comments on the general setting up still stand, its best to start very slightly slack, which was why I mentioned 0.001" movement, you should be able to get it a bit tighter than that before things start to heat up. The spindle should be easy to turn by hand using the chuck. I overdid the model A front bearing, it was getting hot after about 5 minutes. The bearings in that are bronze and tapered on the OD with nuts either side to adjust them. I havn't needed to touch them in the last couple of years. Now I know how, I can remove the spindle in ten minutes.

Edited By old mart on 03/07/2020 21:31:58

I'm glad I don't have a backward dial, I like to see directly the ammount of cut I'm taking. And I prefer to be reading the exact movement of the top slide.

If it is the common type of mill drill, the top front pulley has a large nut on the top. This nut has a left hand thread and the pulley is set on a taper. I took the pulley off the museum's drill mill and it was difficult. We put a puller on it and then applied heat to the pulley, and some time later there was a bang and the taper broke. It was a waste of time removing the pulley, as the bearings it ran in were perfectly sound. Leaving the pulley in place did not prevent the quill from being removed together with the spindle.

Sorry,I thought that the bearings were similar to the model A ones. Are yours in halves with shimmed caps holding them?

When you fit the front and rear main bearings, there should be small pins to locate them and stop them from rotating. And to adjust them, the only way to be sure is with plenty of oil and run the machine at top speed to feel the temperature rise in the headstock casting where the bearings fit. You should start off so that there is about 0.001" movement when you lift each end in turn. Then very slowly tighten the bearings, and test the temperature. The temperature to aim for is just luke warm after 15-20 minutes running. Once the bearings have been adjusted, there should be no reason to touch them. The spindle can be removed without disturbing them. The museum's model A has been happy with semi synthetic 5W30 for years now, it gets oiled every day it is used.

When you fit the front and rear main bearings, there should be small pins to locate them and stop them from rotating. And to adjust them, the only way to be sure is with plenty of oil and run the machine at top speed to feel the temperature rise in the headstock casting where the bearings fit. You should start off so that there is about 0.001" movement when you lift each end in turn. Then very slowly tighten the bearings, and test the temperature. The temperature to aim for is just luke warm after 15-20 minutes running. Once the bearings have been adjusted, there should be no reason to touch them. The spindle can be removed without disturbing them. The museum's model A has been happy with semi synthetic 5W30 for years now, it gets oiled every day it is used.

I can't say what your howling error is, but hold fire on getting the thread in the nut any looser. The most used part of the leadscrew will be much looser on the nut, assuming that it can be screwed right on to find out.

There are a couple of faceplates I just noticed on ebay, they might be the right size for your lathe. 303607680392

Back on topic, my 6 foot flourescent tube in the ceiling of the garage failed the other day, most likely the starter because the ends of the tube were looking good. Nevertheless, I bought a LED replacement which also came with the proper starter (which just says fuse on it). It works ok and I thought I would see if the lathe chuck would strobe. The lathe is a little Warco 7 X 12 with two gears and variable speed to 2500rpm. I had the four jaw chuck on and despite trying all available speeds, I couldn't get it to strobe.

Have you measured the shanks?

ARC provide the footprints of all their machines, try their site.