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View Full Version : Tramming My Mills Head - THANKS



debequem
03-06-2004, 01:51 PM
I don't remember who, but someone suggested using a plate of glass on the mills table as a surface to tram the mills head.

Just finished my Bridgeport' tramming and that idea worked great.

Thanks, whoever it was.

One Bridgeport ready to rock!

Marv

spope14
03-07-2004, 09:41 PM
Sounds like a great idea, I will have to try it sometime. I personally use four 1" gauge blocks to do this (bought them as individuals, all the same "type" / class" and brand.

I also use the same for tool clearance and checking offsets, and i have bad hands (carpel) all said and done, thus a plate of glass would probably have a limited lifespan in my shop.

Forrest Addy
03-07-2004, 10:56 PM
A guy's a damn fool to use glass as a routine shop tool merely to avoid tripping the indicator on the T slots. Think of the breakage hazard. Glass is only flat enough to see through without annoying distortion. That's not flat in machine shop terms.

I've only been tramming mill heads for 40 years and I've never found an improvement on the "movable block" method. Any parallel block tall enough to get you there will do. Smooth radiuses on the corners help the indicator to ride up the the reference face without disturbing the sweep.

Thrud
03-08-2004, 01:11 AM
I would suggest that as a safer alternate to plate glass that you consider a trip down to your friend local neigborhod heavy equipment dealer and ask the shop forman to save you some big honking timkin cups of the next repairs they do. . They are big, round, and ground parallel. and if you want a wider surface, grind it down more on a surface grinder. Cheap, it works, and it will freak your buddies out.

Timkin does make ground spacers, but these are a bitch to find and real expensive in larger sizes.

[This message has been edited by Thrud (edited 03-08-2004).]

debequem
03-08-2004, 07:22 AM
Forrest,

Moving a block is a good idea, but I will defend the practice of glass.

1) I don't need to tram the head on a redgular basis.

2) I tested my glass for flatness and it was within 1/2 thousands, which is the best resolution my indicator has.

Given I can only measure down to 1/2 thousands, the glass was a quick, easy, and effective tool,

However, to your point, there are always better ways to do something.

Marv

Forrest Addy
03-08-2004, 10:35 AM
Sorry Marv. Nothing personal I hope you know but the point you raised sets my safety alarms jangling. I'm against glass as a shop tool in everything but optical flats for the reasons I stated plus more.

Glass shatters; its a safety hazard because when used as a flat it's in harm's way from the tools and normal operations at the bench and the machine. Broken glass in a shop forms an endless hazard because of the sharp spears that fly everywhere. These shards threaten people and visiting critters and because they are all but invisible in oil they threaten machinery too.

I once got three stitches in the back of my index finger because a guy broke his inspection mirror and didn't clean out the T slots afterwards. In cleaning them with a brush and shop towel I somehow ran into his broken glass.

You're correct that glass may seem handy because in thicknesses small pieces around the shop are convenient as flats but their hazard far outweighs their convenience. If you want to replace that piece of glass you find so convenient, find a hunk of cast iron plate and scrape it in flat and parallel. Cast iron may ding but it doesn't shatter.

[This message has been edited by Forrest Addy (edited 03-08-2004).]

Paul Alciatore
03-08-2004, 12:32 PM
Forrest has some good points. I don't know if they totally apply in a one man home shop as I always do a very complete job of cleaning up any broken glass (thanks to my mother's training).

I would add another caution. Glass is made for a variety of purposes. Window glass is made for home windows and table tops and such uses. It is going to be fairly flat as any deviations from flat will produce a wavy image when looking through it. A very good test of it's flatness is to look at reflections off the surface at a very shallow angle, perhaps 1 or 2 degrees. Any deviations will be immediately visible as image distortions.

However, two flat sides do not an accurate gauge block make. They also need to be parallel. THIS IS NOT A VERY IMPORTANT SPEC FOR WINDOW OR TABLE TOP GLASS and the makers are not likely to care about it very much. One piece may be dead on and the next may be off by quite a bit. If the glass is not the same thickness then your tramming will be off by that amount. Mikeing it may not be an answer as the irregularities can be local. Of course, you could just reverse it (like using a level) and check for any error that way. Split the difference.

I don't understand the concern about tramming across the T slots or other irregularities. My dial indicator has a small radius on the tip and I make sure that I do not exceed about 1/4 of that radius when doing such work. The curvature of the tip and slow, careful movement takes care of passing the edges. And the indicator is just as accurate at the end of it's range as in the center.

Paul A.

quasi
03-09-2004, 03:38 PM
How about one of those $40 dollar 6 by 12 surface plates? Handy enough to move off and on the machine and can be used for other things.

Evan
03-09-2004, 04:20 PM
If handled carefully and put out of the way in a safe place when not in use I don't see a problem using glass. I have worked with glass a lot. I used to do some work in a scientific glass blowing shop and I have done quite a bit of stained glass, leaded glass and foiled glass. It's not as hazardous as it seems, proper safety equip is a must of course. Float glass (window glass)is extremely flat and the sides are always parallel due to how it is made. Do not use old window glass as it may be plate glass. All window glass made now is float glass.

The specs for standard float glass are amazingly good. Although the overall thickness spec is quite loose, around +- .5mm it does not vary within the same sheet more than a few angstroms per inch. Parallelism is equally good, under one arcsecond of error. You must take care to properly support it as it is much more flexible than a surface plate, but with care it will do an excellent job.

Randy
03-09-2004, 06:29 PM
Marv - A few months ago you posted a link to a picture of a two-dial tramming device. I liked the idea and said I'd make one. Well, here it is, and it's really slick. I like it a lot. I even put a silly name on it.

http://img7.photobucket.com/albums/v21/rykrisp/tram-o-matic_2000_5.jpg

Peter S
03-09-2004, 07:49 PM
debequem,

You don't actually need 'anything' at all to do this job. It is quite OK to run the plunger of your indicator directly on the mill table surface, you can't get more accurate than that. This is the only method I have ever seen Toolmakers use, maybe we are a bit simple down here?

Also, you don't even need any holder for the indicator, you can often stick the magnetic base directly to the spindle, or collet chuck etc, this allows you to do it quickly without removing any tooling you might have in the spindle. This method requires care however, you don't want to bump it and have the whole lot fall.

ibewgypsie
03-09-2004, 08:29 PM
I use a piece of cut glass to align the belt drives on Harleys. Makes the drive belts last years instead of months. Shimm that rascal flat.

I use my table top to tram. Got a rig I welded to a lathe cut 1/2" bar I put into a kwik switch holder. Been so long since I tilted I am not real sure where it is.

David

debequem
03-09-2004, 09:40 PM
Randy,

That is sweet! Nice workmanship.

Peter,

My table has been flaked and I thought a smooth surface would be easier than trying to locate the indicator between flake grooves.

At least I am making chips now, turning scrap aluminum I buy from a recycler into scrapier metal (I think I am making quality parts if you ask me http://bbs.homeshopmachinist.net//smile.gif ). I am having a blast! http://bbs.homeshopmachinist.net//biggrin.gif

Marv

Peter S
03-10-2004, 01:52 AM
Randy,

My comments above were not intended to be critical of your nice attachment - I like gadgets too! http://bbs.homeshopmachinist.net//smile.gif

Derek13
05-04-2005, 05:05 PM
instead of opening a new topic thought id ask this here!

What is easier for fine tuning the head? Tapping with a rubber hammer? Or using the adjustment screws? (not sure what those are specifically called.. but the ones that tilt the head). I've never seen guys in my shop use a hammer, but to me it seems easier when you get close to give a gentle tap instead of tugging the knobs.

motorworks
05-04-2005, 05:38 PM
"I would suggest that as a safer alternate to plate glass that you consider a trip down to your friend local neigborhod heavy equipment dealer and ask the shop forman to save you some big honking timkin cups of the next repairs they do. . They are big, round, and ground parallel"

Thrud
I picked up a new one from a Russian Boat docked in my home town.
About 8" on the O.D.
Price was right!!!
Works great!!
eddie

ronsmith100
05-04-2005, 08:40 PM
I will take exception to two things here. First of all the use of two (or any number) of "plunge" dial indicators to tram a head is to be avoided. If the dial *plunge* indicator has more than .5 inch travel it is NOT designed to take the lateral stresses that will arise by “tripping” over a groove or gage block at 90 degrees to the shaft.. Sticking those things out one inch is asking for problems. There are short dial indicators of strong constitution that will handle plunkity plinks of a few cavities but they are NOT designed for it. Dial indicators are to be used for movements perpendicular to the tip. For tramming a head use a *test* indicator.
http://www.jjjtrain.com/vms/mill_movments_vert_hd.html

Secondly I have polled a number of machine shops and many of them us a plate of glass to tram the head. I use the gage-block method myself and also I have a Blanchard ground round steel plate (shown in the lesson) that is used as needed. In the grand schemes of things a broken glass plate is not a substantial safety risk in my opinion. Hope this is not too pedantic.

Ron


[This message has been edited by ronsmith100 (edited 05-04-2005).]

madman
05-04-2005, 11:35 PM
If youre mill table doesnt have mortar holes in it and is kinda smooth. Just get your indicator and adjust it so about .010 to .015 or so movement so the plunger doesnt pjut out like half an inch when you tram over the t nut grooves. I use a parallell set when i tram my head but common sense will rule. Good luck. PS with all the advice from the guys on this hsm site you really cant go wrong.

chief
05-05-2005, 05:50 PM
Whatever works for you do it, I doubt many people here are doing aeropsace level work.
Sometimes we get bogged down with trival
stuff, I'm not complaining about anyone but
it's like HSM sometimes, six paragraphs describing how to face off a piece of round
round stock.
I know an old guy who trams his machine with
parallel bar and a feeler gage, it takes about 10 seconds. He works to the accuracy
of the job required. He said what's the point of + -.0005 when the print says +-.100.
His edge finder is a chewing gum and a sewing needle.

mochinist
05-05-2005, 07:15 PM
<font face="Verdana, Arial" size="2">Originally posted by chief:
Whatever works for you do it, I doubt many people here are doing aeropsace level work.
Sometimes we get bogged down with trival
stuff, I'm not complaining about anyone but
it's like HSM sometimes, six paragraphs describing how to face off a piece of round
round stock.
I know an old guy who trams his machine with
parallel bar and a feeler gage, it takes about 10 seconds. He works to the accuracy
of the job required. He said what's the point of + -.0005 when the print says +-.100.
His edge finder is a chewing gum and a sewing needle.

</font>

I agree you don't need to over do it on certain tolerances, but the more accurately you tram the head of your mill in, you will leave a better finish. For example say you have a 4"x4" piece of metal you are facing, if your mill is not trammed in good you will be able to feel bumps where the mill marks overlap eachother. This just means more work for you, because you will have to use a file or some heavy sanding to remove them. This is one area where if I was a home shopper I would over do it.

John Garner
05-05-2005, 09:11 PM
quasi --

Granite surface plates are typically finished on only one face with a perfunctory smoothing of the edges. The underside is usually sawcut and only generally parallel to the face. They are well suited to use as a flat, but not as a parallel.


ibew --

Can I get you to 'splain how to use glass to align Harley drive-belt sprockets? The technique sounds like it might be useful for other non-bike applications.


All you other guys --

I'm with Forrest on the "moving block". A steel parallel used to be my weapon of choice, but more recently I've been using a 2 inch diameter by 1/2 inch thick block of hardened-and-ground O-1 (a keepsake from a now-obsolete test fixture I designed in the '80's).

A compact, lightweight block that can be easily handled with one hand beats a bulky and massive "tramming ring" 99 times out of 100 in my book.

John

halac
05-21-2005, 05:26 PM
I wonder if one could tram the head in by using the base of my mill vise?

If I remove the top piece of my swivel base vise there is a circular bearing surface in the base. Would it be accurate enough to use to indicate from?

Hal C. , www.teampyramid.com (http://www.teampyramid.com)