Precision Tool From Scrap

[Blogwitch]

Another transfer over topic, this time a dead easy precision tool you can make.


Grab yourself a bit of old steel tube.

Mount it up in the lathe and clean up the outside for whatever length you want, I made mine about 3" long.

Very gently, lock up your saddle, and carefully face the end.

Deburr the inside and very gently remove the outer sharp edge with a bit of emery cloth or W&D.

Part off the bit.

Turn the new part around and lightly grip it in your chuck, gently face the end and give it a good clean up. I put a large outside chamfer on it, to save this end being confused with the other, which is the working end.

You have just made yourself a perfect tube square that can be used almost anywhere a normal cheapo Chinese square can be used. They are very good for setting things upright in your vice jaws because they can be wider than a normal engineers square, and don't want to fall down into the gap.

Make up various lengths and diameters, you will find a use for them all, eventually. Big chamfer to the top whilst in use.

Another hint, you have to make sure your lathe turns perfectly parallel, otherwise they will not be square.



John

 

[seagar]

I like that and sooo simple even I could and will make one .Thank you. :bow:

Ian (seagar)

 

[mklotz]

John,

Excellent write-up. I've made numerous cylinder squares over the years. They're extremely handy. One serious advantage is the ability to make up very short, squatty ones to use in setups where a normal square simply wouldn't fit.

I remember reading, many years ago, a construction article for a cylinder square that incorporated a central rod used as a distorting device to fine tune the squareness. It may have been in Model Engineer before it turned into a railroad rag; my aging memory can't recall. Are you (or any other of our readers) familiar with such a device? I don't recall the details of operation and I would like to add it to my mental design notebook.

 

[Herbiev]

Ingenious. Many thanks plus a KP

 

[steamer]

The error can be quantified with a reversal ...a very neat feature of a cylindrical square.

Dave

 

[Blogwitch]

You are quite right Dave, and as Marv says, they are easy enough to make, even for a one off job.


Just to answer Marv.

I have never come across that article, but would sure like to see it.

I do suppose the idea must be in one of my old e-books somewhere, but finding it is the problem.


John

 

[Kerrin Galvin]

Hi Guys,
Marv / John I'll have to check but if memory serves (getting older so its anybodys guess) Guy Lautard shows a build in one of his Bedside readers

Cheers Kerrin

 

[Blogwitch]

Hi Kerrin,

On your say so, I looked through all three indexes of the bedside readers, and the only mention I came across was how to make a tube square, that was in book 2, and basically very similar to how I showed my version.


John

 

[moconnor]

Hello All,

What Marv and Kerrin may be thinking of is an article in Guy Lautard's 'The Machinist's Second Bedside Reader' titled: "AN ULTRA SENSITIVE DIAL INDICATOR BASE" (pp 83-84) which uses a cantilevered beam inside a thin walled tube. Not a precision square, but a very fine adjustable surface plate stand for a .0001" dial test indicator (or similar). That Bedside Reader also has a great article on how to make and check a master reference square, although not a cylindrical one like John made.

The very best article that I have read about making a cylindrical square was in Model Engineer's Workshop No.37 (Sept/Oct '96) by Bill Morris titled: "How Square Is My Square". He documents how to build your own cylindrical square to a very high standard. He is one of the very best contributors to MEW and I can highly recommend every one of his articles.

Incidentally, if you subscribe to MEW or ME you can view back issues online and print off any drawings or articles that you want. MEW goes all the way back to issue No.1 and ME currently goes back to 2001 (Vol.187 No.4153). This alone is more than worth the price of the subscription as having access to this while traveling or visiting relatives out of town is priceless.

Regards,
Mike

 

[Kerrin Galvin]

Hi John,
Well I did say I was getting old . I'm at work so couldnt check the bedside reader's, sorry. Looks like Mike found the article though.
Cheers Kerrin

 

[mklotz]

Mike,

Yes, you've nailed it. I checked my MBRII and that's what I was remembering, though, in my aging brain it turned into a cylinder square. Sorry if I caused any confusion.

 

[moconnor]

Hey Guys,

When I read your post earlier Marv, I thought the same thing and went searching through my files trying to find the article. I am glad that I found it though before I tore through all of my files.

Regards,
Mike

 

[ttrikalin]

I remember reading, many years ago, a construction article for a cylinder square that incorporated a central rod used as a distorting device to fine tune the squareness. It may have been in Model Engineer before it turned into a railroad rag; my aging memory can't recall. Are you (or any other of our readers) familiar with such a device? I don't recall the details of operation and I would like to add it to my mental design notebook.

This is in one of guy leotards books.

I will try to unearth them to give a page reference, but not this weekend.

 

[mklotz]

This is in one of guy leotards books.

I will try to unearth them to give a page reference, but not this weekend.

Tom,

Before you spend a lot of time on the search, better read post #8 in this thread.

BTW, I don't think Guy Lautard is going to appreciate the new last name you've given him.

 

[Captain Jerry]

Very useful topic and a very useful device. I made a pair a few years ago and the first thing they were used for was testing the squareness of the lathe (ways parallel to the spindle axis), which also verifies the accuracy of the squares. By placing two cylinders together on a flat surface with a bright light behind, any out of square is clearly visible. The error angle is doubled.

If there is any difference in the brightness of the gap, the cylinders are not square and neither is the lathe. Mine were not absolutely perfect but for my purposes, they were close enough. I keep this infinitesimal error in mind if it might effect the job at hand and it never does. Some of you, with better equipment and more demanding work might take corrective action.

Jerry

 

[f350ca]

I've been pondering this and don't think it matters if the spindle is parallel to the ways. The cut will always be square to the stock if the jaws of the chuck or collet is parallel to the spindle.
If we take it to the extreme, say the spindle was at 45 deg to the ways, you'd get a chamfer on the stock but the cut would still be square to the stock.
If the stock was canted in the chuck (not parallel to the spindle) then the end would not be square to the stock.
Jerry would the error your seeing be the jaws of your chuck not parallel to its axis?
Does this make any sense or am I not visualizing the operation correctly.
Greg

 

[MachineTom]

It would not matter if the jaws were out by .050", you have turned the OD concentric with the spindle. What would matter is the loosenes of the spindle bearings, as that would allow random movement of the spindle and the OD would likely not be very round, which would kill the angle to the face. Any wear on the ways that could lead to taper would also hurt the accuracy of this piece.

The issue I see is that the surface finish of a material like black pipe, does not lead to real accurate gaging, much better than an eyeball, but less than a well made machinest square. If it were ground round, and faced it would be much better from an accuracy point of view.

 

[Captain Jerry]

Greg

Any error in the chuck jaws is resolved when the cylinder is turned it will be concentric with the spindle axis and the facing cut will be perpendicular to the spindle axis, HOWEVER, if the spindle axis is katywumpus (not parallel) to the ways, the turned cylinder will be very slightly cone shaped and the surface will not be square to the base.

When I looked at what it would take to square up my headstock on my 9x20, I gave up. The headstock has V grooves that sit on the Inverted V ways. Non- adjustable as far as I could see. But on some lathes this alignment is adjustable. I once owned and used a Unimat SL and every time the headstock was changed from lathe to mill and back, it had to be realigned.

I don't have any experience with other machines but I suspect that there are lathes that allow this adjustment.

Jerry

 

[Blogwitch]

Goodness me Tom, you are like death in an overcoat when it comes to replying to a post. Do you always look for 'what if' faults?

I showed a very easy way to obtain, with a little care, a tool that could be used with confidence to set something up square, ideal for a beginner to tackle and get a perfectly acceptable result to use in their workshop for lots of jobs. OK surface finish does need to be reasonable, and of course the end needs to be square to what has been turned.
I have used mine frequently, and I haven't ruined a single piece I have used them on, and so far the sky hasn't fallen in on me, yet. So what is wrong with them?

Not everyone can afford grinders for their lathe, or to buy multi hundred buck tooling as you suggest needs to be done.

Please remember, this is a site that TEACHES more than it makes, and replies, if possible, should be geared towards that goal, not drag things down at every opportunity you can get.


John

 

[f350ca]

Jerry and Tom, that makes sense, Hadn't looked at turning the dia, that corrects for misalignment in the jaws, but if the axis is off you will as you said make a cone.
Thanks this is what I like about forums.
The headstock was way off on the old Colchester I picked up a few years ago. Its set up as I remember with only one corner doweled so that you can swing it straight.