Milling a 45 degree ‘v’ slot

[Lee Jones 6Participant @leejones6]

Going okay so far, but it's such a faff.

I still like the idea of a repeatable sine table based setup with stops, but I just can't picture what that would d look like without purchasing some kind of tilting table.

[JasonBModerator @jasonb]

lee, have you worked out how to remove the pin from the post so that you can offer up the post to your holder at this stage for test fitting?

[Lee Jones 6Participant @leejones6]

Doesn't quite work like that I'm afraid.

[thaiguzziParticipant @thaiguzzi]

Posted by Lee Jones 6 on 21/05/2020 11:00:12:

That's my plan, although I'm limited to 4 at a time with my set-up.

It's okay, I was only jesting.

My plan is to make say 4 or 8 of my own and buy some from knock-offs when they come back in stock.

Yours look amazing by the way. Are they T1s or T2s?

Edited By Lee Jones 6 on 21/05/2020 11:00:48

Thank you.

Er, T1 ish (?).

73mm long rings a bell, 35mm high, stock a 16mm tool slot/capacity.

Originally sold for Boxfords/Bantams etc.

[John BaronParticipant @johnbaron31275]

Hi Guys,

Ooo bringing back all the memories of why I got rid of my QCTP.

[Howard LewisParticipant @howardlewis46836]

Again, many examples of how ingenious members are in finding solutions to a particular problem.

Me? I either clamp the work in a vee Block in the milling vice, (Usually square material, or use my small three way tilting vice, instead of a tilting table.

Occasionally prop up the work with a centering square, an angle plate, or set it with a digital angle gauge.

But having said that, I am not very adventurous (and come to grief when I am ).

Howard

[JasonBModerator @jasonb]

Posted by Lee Jones 6 on 21/05/2020 14:58:11:

Doesn't quite work like that I'm afraid.

Forgot about that bit in the middle may be worth doing the tee slot first on the others?

[Lee Jones 6Participant @leejones6]

So I just trammed the head back to 0° (vertical).

How does 0.1mm over 480mm sound? So 1mm over 4800mm (4.8m).

[Lee Jones 6Participant @leejones6]

I fear this thread may get off topic pretty quickly.

If you'd like to follow progress or get involved in further discussions, I started a thread over at:

[Project 3] Dickson T1 Tool Holder

[Martin ConnellyParticipant @martinconnelly55370]

Lee I can't comment on what are good or bad figures for tramming, I have never had to do my mill as it does not tilt and it has always cut the correct circular pattern when using a flycutter. I know I'm probably lucky with this but it was a second hand machine and I don't know if it was done before I got it. Anyway I digress, the thing I was going to suggest is a nice piece of glass to put over the tee slots for the purpose of tramming. It will allow you to sweep the arm around without having to lift it over the slots. Modern float glass is pretty flat and of uniform thickness. If the tram is checked and then the glass is rotated 180 degrees and the tram re-checked it will show up any error in the glass. You may be able to use some from a picture frame but it may be a bit thin and so fragile.

Martin C

[Clive FosterParticipant @clivefoster55965]

Really accurate tramming is a complete PIA job. Especially when you don't have a reliable, backlash free, screw controlled adjustment. Most home shop machines tend to be push'n hope adjustment so success is down to how many cycles of "nearly right, one more push, darn too far" you can cope with.

Bridgeports et al have a worm drive which is less effective than one might hope due to backlash and weight. Doesn't help that when set up in the usual manner Bridgeports, and other mill heads, tend to be in or close to balance when trammed. The motor assembly on Bridgeport style machines can be swivelled to one side allowing you to bias the weight significantly one way so you are always working against a stabilising load.

With the common ME size machines I'd be sorely tempted to hang a weight a foot or so out to one side on a suitable framework to bias things one way. Perhaps add a jack screw so you have positive control of the movement, or just arrange things so you have anice long lever to pull on. If nothing else a screw jack means you can let go without things moving on you. When I had a squarehead, Chester Lux style mill, I found it hard to hold the head steady whilst simultaneously tightening the bolts. Not enough arm joints methinks.

I'm inclined to think that a stout post with flat foot exactly at right angles grasped in a collet or, better, held in the spindle taper would be a quick way to produce tramming accuracy acceptable for most practical purposes. Basically bring the head down so the plate sits flat on the table. With the head bolts suitably loosened all should come close to aligned. I guess 6" or so diameter would do for the foot, bigger being better of course, so getting post and base mutually perpendicular is a simple lathe job well within the capability of most ME size machines.

Handy for taking the head off if need be too.

Alternatively perhaps a pin 'n slot pivot on a similar style post working in a bracket bolted to the table would give decent screw controlled movement.

Clive

Edited By Clive Foster on 22/05/2020 13:33:57

[not done it yetParticipant @notdoneityet]

I have a large brake disc which I am going try at some point (when tramming becomes an issue). First thing will be to try by measuring in one position while rotating the disc, for a test. Any comments before I go to the trouble?

[Dave SParticipant @daves59043]

When I made this one:

I nodded the head, rather than tilt it.
Retramming on my TOS is simple, if heavy. It has a pair of ground taper pins that locate square, one for tilt and one for nod. Within a thou over 12” takes as long as winding the screw back to get the pin to fit.

Dave

[Lee Jones 6Participant @leejones6]

No nod in my machine unfortunately, else I would do that.

[John BaronParticipant @johnbaron31275]

Posted by not done it yet on 22/05/2020 15:55:41:

I have a large brake disc which I am going try at some point (when tramming becomes an issue). First thing will be to try by measuring in one position while rotating the disc, for a test. Any comments before I go to the trouble?

Brake discs are about as flat as you can get ! If you think about it if they weren't the brakes would judder something awful. So no point in rotating it and checking unless its an old one and its warped.

The swinging arm and a dial gauge will tell you all you want to get the head back in tram !

[Oily RagParticipant @oilyrag]

Buy a shaper! This sort of job is what they excell at.

[peak4Participant @peak4]

This is my tramming gizmo, made broadly to a John Moore, "Bogstandard", design.
I actually made it with an MT2 shank, to go directly in the spindle, rather than a parallel stub to fit a cutter chuck, as John described. Both my mills are MT2, so it's usable in either.
I just reasoned that missing out the chuck was one less item to throw the accuracy.

The advantage of this design, is that the plane of the two flats at the bottom is exactly perpendicular to the axis of the morse taper arbor.
The length of the bottom arm was governed by the maximum I could spin in the Myford gap bed.
It means you can just sit the base on a level surface and zero the dual gauges.
Then fit the device to the mill spindle and bring the table up to suit. As soon as the gauges start to read, it becomes obvious if the head isn't perpendicular to the table, and easy to adjust accordingly, with an immediate direct readout.

It also show wear on the slides and of the table is tilting at either end; mine does unfortunately, due to the weight of the non-standard table drive motor on the Centec; The Westbury is OK.

The clocks were £4.50 each off ebay, yes cheap and nasty, but still accurate, and work fine for this application.

Bill

 

Edited By peak4 on 25/05/2020 23:49:22

[Lee Jones 6Participant @leejones6]

Thanks Bill.

I did consider making one of these (and might still yet), but I already have a 'healthy' list.

Edited By Lee Jones 6 on 26/05/2020 07:52:46

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