Member postings for old mart

The video maker said that the tubes were bored with a 0.005" taper, can anyone tell me how he did it, was it magic?

Some more pics of the progress. I fitted the rubber swarf guard which Mike has made. It is a rather poor design which has to be moved up and down when the knee and Y axis are moved, there is really no alternative. The other one has the spindle speeds, please tilt your heads to view.

I recon all the chips were being expelled forward, the coolant leaking back was free of them, and there were turnings at the chuck end. I noticed the hole in the tube was not round, or was eccentric with the OD, the cut varied from 1/8" to 3/8" which was another reason for the wooden damper. Also, I would guess that the boring was carried out in one pass, although it was odd to see an area at each end turned for using the steady, maybe the boring was done from both ends due to the length of the tube. Checking out the video again, I realised that two lengths of tube featured, the short ones did not need turning around.

Edited By old mart on 25/10/2019 19:49:24

If the bushes were Oilite, the drill would not have any difficulty, it drills very easily.

You will have to make a fixture to hold the reamer dead straight, and buy a proper spiral fluted reamer. There is not much of a chamfer on the hole to keep the bush in place after staking. Does the reamed bush get inspected before fitting the bearing? Could you get away with lapping the bush? I have fitted lots of these type and the variation where the bearing fits directly in the hole and has a grooved edge which is staked. Roller staking was used.

You may be able to get away with careful measuring and only ending up with about 0.05mm undersize, then use the reamer to rub out the rest.

Edited By old mart on 25/10/2019 19:12:03

I have a set of imperial ones, they have seen better days, not one would pass inspection, I had to scrape the rust off most of them. But for my purposes they are as useful as a brand new set. It is unlikely that I would ever need to measure less than 0.0005", and even a stack of half a dozen would be only that half thou down.                                   My firms inspection department had a box of slip cages, and I said, what a wonderful thing. The chief inspector replied that they are better than nothing when you are desperate.

Edited By old mart on 25/10/2019 17:33:45

I would use a four jaw independent chuck for a thin walled bush, and bore it to finished size. You need a couple of thou clearance when in use in the car, no reaming needed.

I bought one of the Indian made Soba 6" h/v ones, and found it was not very secure when vertical. It now has a couple of threaded holes in the base which allow a tiny angle plate to be attached which allows additional clamping to the bed.

Do you have a manual drawbar? I looked for the split collets on ebay UK and there were none, but I noticed some er32 ones like this which were shorter than your er16, there may have been other er sizes available.

**LINK**

Unfortunately, the wall thickness of your nuts is too thin for simply replacing the thread by bushing, I think the complete nut assembly will have to be replaced. The pictures do not enable a guess at the actual size of the thread. What is the thread pitch, there seems to be a choice of 1mm, 40 tpi or 20 tpi.

Lidl have recently had two of these for sale, one battery and one mains, I bought the mains one, it was £14.99, I think the battery one was more. The mains one has 1500 lumens@ 20W and is intended for a security light, it comes with a remote control programmer. I intend to use it as a light for the mill, on an adjustable arm.

Those 18650 lithium cells are easy to get hold of if you need some.

Edited By old mart on 24/10/2019 22:18:34

For potential fitting of a Myford backplate onto the spindle, there is a shoulder just below the spanner flats. You could make a tubular collar for the backplate to tighten onto. Unfortunately the backplate will have to be machined in situ on the mill for it to run true, an easy job if you think of a vertical lathe and hold a lathe tool in the milling vise. Expecting the backplate/ collet chuck to run true if you were to fit it on the lathe is very long odds against. The mill and the lathe would each have to have their own backplates, but could share the collet plate.

I bought a 9" faceplate on ebay very cheap, for the Smart & Brown model A. I knew what it was by the casting number on the rear. I cleaned everything and set up a tool to skim it on the lathe, and something got into my head that I should check it first. It ran 0.0005" tir, so the skim was cancelled.

The RDG collet chuck and backplate is a very good buy, and as mentioned, more compact than my link.

The Tom Senior Light Vertical mill which we have been working on has been converted from MT2 to R8, it came with their version of a Clarkson Autolock for screwed shank tooling, it has a threaded collar at the top which is tightened against the end of the spindle. This stiffens up the rather flexible MT2. I wasn't happy to use MT2 which was why I converted it to R8, also to use all the R8 tooling that we have.

Edited By old mart on 24/10/2019 21:22:33

That peak 4 suggestion sounds promising regarding the spindle nose threads.

**LINK**

As for the lack of enough metal in that collet holder, it is the only one I could measure. There may be others with greater lengths, but it would be a lottery whether they would work, I will see if my R8 ones have that 0.733" bore in them.

Edited By old mart on 24/10/2019 19:45:48

I set up one of the jaws of my Toolmex light 6" chuck, which is in almost new condition in a similar fashion except for having a cylindrical surface for the tip to bear against. The ground surface if the jaw tip is not flat, it has a radius. The jaw is exactly 16mm wide, so I used the shank of a 16mm endmill. The measured slope is much less than yours at 0.0005", 0.0127mm over approximately 40% of the length of your jaw.

I have some dimensions of the MT2 er25 collet holder that I have. It is one of the cheap Chinese ones from ebay. The 0.7" large end could be compared with that same diameter on your Clarkson to get a reasonable idea of how deep it will seat. There is some scope for adding flats, although the milling might require carbide cutters. I used solid carbide endmills to put spanner flats on both of the R8 er25 collet holders that I bought before it was common to include the flats from new.

Edited By old mart on 24/10/2019 19:00:03

The forces on the insert are mostly down through the toolholder, as mentioned, the screw does not have to be super tight or strong. It is more important to ensure there is no swarf stuck between the insert and the toolholder when it is fitted. I do, however, have a Ceratizit shell mill with 5 round inserts which is rated for 11000 rpm. It stresses that if the maximum speed is used, then the screws are changed at the same time as the inserts, which can index 8 places before discarding.

It looks like a miniature version of a DUKW

Hi Jerry, there will be lots of old vehicle buffs on this forum, lets hope the workshop has some nice tools in it.

Too much bother, you could sell the Clarkson and get a MT2 er25 which goes to 16mm. It should not need the locking flats. Only buying one and fitting it will allow you to find out if it is viable. It wouldn't cost much to prove it one way or the other:

**LINK**

 I have an er25 MT2 which I could measure to give some idea if adding those drive flats would be feasible, but it is difficult to judge exactly how deep the tool goes into the spindle. Hopefully, I will remember to measure it tomorrow (Thursday).                                                                                                                                                                          Your Autolock is a rare bird, and may have been made in this form just for that one make/ type of mill.

Edited By old mart on 23/10/2019 20:42:01

Edited By old mart on 23/10/2019 20:44:34

Making a four leaf clover tensioner seems like so much bother, and it only fits one size of jaw. That's why I drilled the jaws with a carbide drill and use any of several rings of different sizes bought cheaply on ebay. The rings are primarily for use with the serrated jaw chuck which requires tensioning every time the jaws are bored.