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form_change
03-19-2011, 05:35 PM
In the flurry of activity that has engulfed me of late I cleaned and painted the lathe tailstock. I've always though that some graduations would be good and the cleaning has reveled some very faint etched markings on the back end of the tailstock ram.
However 50+ years has rendered them next to useless, with the most used section (the front) unreadable and the rear section only just visible.
My first thought on making these usable again was to machine a shallow groove in the ram (this should be possible because a previous owner has filed marks in the ram, so it's not dead hard) and then embed a trimmed down section of steel rule in the ram. The existing scale markings only extend for 3 1/2", so I'd be replacing with something around this long. (Official travel according to the lathe specs is 4").
My question is how best to secure the new scale onto the ram. I had thought of easy-drive pins as they are used quite a lot to hold thin metal like this (eg name plates and threading charts) although even smallest size would require the heads to be modified to fit within the ram profile.
The ram is oil lubricated so any adhesive would need to (effectively) withstand being soaked in oil. Welding seems a little extreme. Any other ways that people have seen or can think of?
The ram diameter is 1 1/4", the existing flat for the scale is 5/16" wide and the ram is bored for MT2, so there is roughly 1/4 of depth to play with.

Michael

EddyCurr
03-19-2011, 06:39 PM
What about removing the ram and reengraving measurements on the ram?

As an alternative to embedding a rule in the ram, is it feasible to add a
pointer to the ram and mount a rule on the tailstock for the pointer to
indicate against?

.

form_change
03-19-2011, 07:29 PM
I thought about re-engraving the graduations but most of the engraving shops we have around here have a poor understanding of accuracy - it would look the part but may not measure correctly, and that would annoy the heck out of me. They also don't seem to be able to do anything without 'art work'. I had a small label made up a couple of months ago that cost me $10 but the artwork to prepare it was another $30. I could possibly take it to a tool room and get it done accurately but that would cost hundreds.

Mounting an external pointer (or even a digital scale) is possible, but I'm trying to avoid cluttering up the machine. There is a graduated dial next to the handwheel but I find direct reading is more convenient in some cases. Because of oil points and handles on the top surface of the tailstock, it would have to be something hanging in space - hard to get it looking like it was always there. In this case augmenting the original design intent has much more appeal.

Michael

rohart
03-19-2011, 08:08 PM
I'm in a similar position. My ram either never had any scale, or had etched markings that have long since disappeared.

I plan to mount the ram in another lathe and use a threading type tool to mark the scale. I do have worm driven indexing on this lathe. For a 10cm scale it would mean 100 or so lines, but it's a once off, so it wouldn't be too arduous.

I wouldn't get any numerals that way, and I don't have a punch positioning jig yet, so that'll have to wait.

becksmachine
03-19-2011, 08:34 PM
Take the quill out and mill a shallow slot that will allow you to glue in a steel rule. I could show a photo if interested.

Dave

Toolguy
03-19-2011, 09:26 PM
You could machine a shallow slot a few thou. deeper on the edges than the thickness of the scale, a thou. or 2 wider than the scale, lay the scale in the slot and lightly peen the top and bottom of the slot to retain the scale. I would put the scale at a 30 to 45 degree angle around the ram, rather than on top to make it easier to see the markings.

Pete Burne
03-19-2011, 09:54 PM
Becksmachine: Dave

Your suggestion is exactally what I did a few years ago. Looks good & works good.

Quick and easy if the quill is not hardened.

Pete

lazarus
03-19-2011, 10:01 PM
You could pull the quill, put a blank arbor in it and chuck it in the lathe. Put a sleeve over the screw that lets it go half way into the quill, and put it in a steady. Use your carriage to mark it where you want. Roll the chuck by hand to make the marks.

If you can index on your spindle, you can use that to limit and alter the lengths of the marks. If not, you can make stops to clamp to the bed to limit the chuck travel. 2 pipes on a piece of flat with a nut welded on top and all thread with lock nuts will let you lengthen travel on preferred marks after all are scribed.

A 4jaw would work best for this as the two side jaws would hit the stops square.

Tool profile will determine size and depth(your choice)

A lot of set-up for a half hour work(as always), but it could be put back like original if you know what that was.

Guaranteed never to fall off.

Ben

justanengineer
03-19-2011, 10:36 PM
I would simply remark it yourself by either using a flycutter on the mill or a shaper to get very accurate marks, then either take it to the engravers or simply use a stamp set to carefully mark it. If youre concerned about originality for the future, its not too difficult to make a new ram.

chipmaker4130
03-19-2011, 10:44 PM
The ram is oil lubricated so any adhesive would need to (effectively) withstand being soaked in oil.
I used 'bearing retaining compound' to secure some .045 brass strips in a .020 deep slot in steel. So far none have come loose. My slot width was such that the strips fit snugly. I suspect such a compound would work for you too.

philbur
03-20-2011, 08:47 AM
Rather than use easy-drive pins you could put a shallow counter sunk hole in the top face of the rule and preen a plain pin into the counter sunk recess. Kinda standard riveting practice.

Phil:)

John Stevenson
03-20-2011, 09:01 AM
Or a version of this to suit your layout.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/tailstockdro.jpg

djc
03-20-2011, 09:29 AM
My question is how best to secure the new scale onto the ram.

The 'Swiss craftsman' way to do it would be to make the slot a dovetail and the scale similarly. To stop it sliding along the axis of the tailstock, a shallow countersink/dimple in the back of the scale which mates with a spring and ball bearing in a shallow hole in the ram.

form_change
03-26-2011, 03:11 AM
In a spare moment today I decided to do something. I used a high contrast 6" rule graduated in tenth's that I bought a while ago that I thought would be good for the light conditions. The act of cutting it to size with an abrasive disc was enough to burn the black off, so it's now just a normal looking engraved rule. I would have thought the black would be more durable than that but? The original marking was in 16th's but I thought that tenth's would be a little easier as most of the things I do are in decimal

http://i1140.photobucket.com/albums/n574/form_change/P1010087Small.jpg

I carefully trammed the mill up and then lined up the existing flat so that I was on top of it. An interesting idea for others to try. I have one of those cheap digital angle indicators. I zero'd it on the mill table and then used that to ensure the flat on the ram was the same angle as the mill table. According to the instructions it should have been within 0.1 of a degree.

Earlier I reported that the ram had some file marks in it so was not particularly hard. True, but I still munched up a couple of HSS cutters before deciding to dig out a carbide cutter. It may have been case hardened perhaps. Anyway, a 1/4" carbide was up to the job although it needed a couple of passes to get the target 5/16th width. The flat to the right of my cut is the original level

http://i1140.photobucket.com/albums/n574/form_change/P1010085Small.jpg

I put a groove in so that the cut down rule was just (a thou or two) under the profile of the ram. I roughed up the back of the new scale, chamfered the rear edges and following chipmaker's suggestion used bearing lock compound to hold the scale in. This is the finished result -

http://i1140.photobucket.com/albums/n574/form_change/P1010093Small.jpg

Thanks to all those who made suggestions.

Michael

gary350
03-26-2011, 10:00 AM
Buy a Black paint stick and rub it on the scale. Wipe off with a rag all the black in the grooves will stay.

McMaster Carr and WW Grainger both sell paint sticks.

A black wax pencil might work I have never tried that.

George_Race
03-26-2011, 07:33 PM
You could be really different and mount a Digital Read Out on your tailstock. It really works sweet! Check out my pictures at the following link:

http://www.mrrace.com/Mini_Lathe_DROs/

George

Black_Moons
03-26-2011, 07:39 PM
This sounds like a good excuse to work on that spring loaded engraving tool you allways had on your project list, Then mark it in the mill, And take it to engravers for the numbering (if its even needed. Just a good |....|....| scale is all you really need)

Toolguy
03-26-2011, 08:03 PM
You could be really different and mount a Digital Read Out on your tailstock. It really works sweet! Check out my pictures at the following link:

http://www.mrrace.com/Mini_Lathe_DROs/

George

That's a well done project George. Thanks for the pictures. Welcome to the Forum!:)

form_change
03-27-2011, 04:12 AM
George, the external digital display was suggested but for a whole bunch of reasons revitalising the ram as I did had the most appeal to me. Some people like them but I wanted to keep the lines of the lathe as clean as I could. I'm also mean enough that I don't like buying batteries for these things all the time - you should hear my thoughts when the light in my welding helmet starts flashing. Still, horses for courses and your adaptation looks neat.

Gary, since taking that picture I've used a laquer-stick to blacken the numbers. Because the etch is a nice deep one, the contrast was good enough to pick out without it but the black does help. It will be interesting to see if it stays there with the oil that is present in the tailstock.

Black_Moons, the engraving may be closer than you think! The next mill is a universal type that can drive a dividing head to create helical gears. However, I've been told that if you hand crank them you can drive back through the table and use them as a dividing engine for precise scale marking. (The scale is fixed to the table - the dividing head is used purely to provide a gearing down for fine divisions) I have a high speed head so with a carbide engraving bit I may be able to do linear scales soon myself. Something else to try

Michael