Tom Senior depth of cut

Hi Guys

I am still very green to machining,

it all started with the bulk buy of a small Mill/drill (that I went on to sell), some old time horizontal milling machine (that I went on to sell) and my Myford super 7 That I rebuilt and have kept (see photos in my blogg)

Not having much money, all of the stuff I buy is second hand and needs a lot of TLC

my last two purchases were a Tom senior M1 and a tom senior Major,

The Major I had to travel from London to Scotland to collect !!!!!!!!

It was a good price and it came with a S head (that I am yet to paint and fit) it also came with a notching head (new as in un-used)

I have been EXTREMELY lucky to have found a new old stock (never used) Knuckle head for the Tom senior M1 so at the moment, my M1 has the knuckle head fitted and the tom senior major is set up in the horizontal mode.

I must say, I have a feeling all is not right with either machine!!!!

It could be as simple as the stands I have built for them?????

they both rest on four feet (each) which are no more then some large M14 bolts, no pads under neither

I do seem to get a lot of vibration when I try a deep cut say 30 thou

I cant plunge cut because it vibrates to much, unless i take it slow and shallow

I have adjusted the gibs as far as I think is ok, and the work is always held well

what should I be able to expect from the two mills????

The M1 is a one HP three phase motor and the major is a two HP three phase motor both running of separate VFD

Edited By Piero Franchi on 10/11/2017 08:45:48

To be honest, I have never bought new end mill !!!!!!!!!!!!!!

Some are new old stock, some are used, and yes, the vibration is a lot worse with older cutters,

Ill have to try with a new cutter and see if its 100% better

I am sure it will be a lot better, but surly you cant need to use new cutters all the time???

Assuming you're running the cutter at a sensible speed increase the feedrate and make the cutter work rather than rub.

Andrew

Andrew, if memory serves me, (as I have not had enough milling time to remember) deeper cutting is worse

Do you firmly lock down both x and y axes when plunging, or both the other axes when traversing cuts?

I would suspect that a basically free-standing situation is not helping either.

Is your stand construction sufficiently rigid?

How are you plunge cutting?

Are you climb milling?

Cuts have 3 dimensions - depth, width and feed rate. 30 thou should be easily accomplished but it depends on the other two dimensions as well as the material being cut and cutter size and type.

Do you use cooling or cutting aids?

I would expect, given suitable combinations, that you should be able to absorb most of the available motor power - but that may be reduced to take into effects of wear. A compromise, as always.

Giving more explicit examples would help the dignosis of your problem(s).

The little time I have spent on my mills has been stripping it down, cleaning and putting it all back together (the major, as it was very dirty when I collected it, the M1 was very clean and needed very little doing)

actual milling time is more a case of doing something that,s needed as in fixing something.

I have not done a project on the mill and the jobs I have done, were more a matter of what works!!!!

I don't have a set of rules that I follow as such, I just go on what I think is wright.

So I wont look up feeds and speeds and depth of cut, I cant say what I have been doing either !!!!!! sorry

I know this does not help.

I do know I lock the table in what ever axis is not moving, I hand feed at a rate that does not give problems,

My base that I have built is very ridged, it is a thick wall box section square with these adjustable feet on it,

Ill have a look on my phone and see if I have photos of it that I can up load.

My only concern with the stand was it sits on the adjustable feet that have a very small footprint contacting the concrete floor

Edited By Piero Franchi on 10/11/2017 10:38:11

Just added two photos in my blog

as you can see the stand should be up for the job, but like I say, the bolts sit directly onto the floor (not on any type of pad)

I meant feedrate, not depth of cut! If the feedrate is too slow the endmill will chatter whatever the depth of cut. If the endmils are a little dull then a good feedrate is even more important. With low feedrates the cutting edge rubs as the tool deflects away from the work. Eventually the forces are such that the cutting edge bites and starts to cut. Then it leaves the work and the process starts all over again with the next tooth. Equals chatter.

If you have a proper cut going it doesn't matter if the mill isn't bolted down. Almost none of my machines are bolted to the floor.

Andrew

The only person it won't help is you, I am afraid.

There has been speeds and feeds data out there since machine tools began, for good reason.

Once you are experienced by all means fly by the seat of your pants, but it is sensible to get that experience at least loosely following established custom and practice.

You can also surely see what a futile exercise it is coming on here asking for help, when you cannot give a good diagnosis.

Much of my working life was spent in a problem solving role.

Mantra #1 is, you cannot fix the problem until you know what the problem is!

If you cannot advise what speeds and feeds you have been using, then you will just have to either start noting them, or try all the permutations until you find something that possibly works.

The latter exercise is known as the 'blunderbuss principle', and isn't very efficient.

None of this is meant as a criticism, only an observation 

Edited By David Standing 1 on 10/11/2017 13:11:47

The photo in your album of the major looks like it is sitting in mid air on dinky little bolts about 4 inches long. probably not the main problem but take those out and lower it onto bits of paving or paving bricks (but not soft house bricks).

If you are using a 4 flute endmill don't try to push it full width sideways into a block of metal. You have to run along the side of the block no more than 1/3 of the width of the cutter at a time. For testing only go down 1/2 cutter width.

Hi Piero. I think you're starting with too many disadvantages making it hard to pin down what's wrong. It could be one or more of:

• Unknown cutter probably blunt
• Milling machines in unknown condition
• Testing on an unknown metal (could be work-hardening)
• Inexperienced operator
• Wobbly stand

I'd try and eliminate some unknowns.

• Get hold of some mild steel or an Aluminium alloy intended for machining and use that as a test piece. Don't mess with scrap metal.
• Buy a new sharp cutter or have an old one properly sharpened.
• Don't guess if you can avoid it! Do some research or ask on the forum. You need to establish a reasonable rpm, depth of cut, and feed-rate. RPM, depth of cut, and feed-rate vary depending on cutter size and the material being cut and getting it wrong can cause chatter. (I'm forever in Andrew's debt because he drew my attention to the importance of feed-rate. Before then I had problems despite getting the depth of cut and rpm rate correct because I fed the cutter too slowly causing it to rub.)

I have a set of HSS 2 and 4 flute cutters that all work well apart from the 12mm 2 flute. It chatters furiously. I know why - it's the cutter I use most and it's blunt. Nothing I do stops it chattering. Not the machines fault, or mine, or the metal I'm cutting - it's simply that the cutter needs sharpening. Given that you have machines with good specifications, it's quite likely your problems are simply due to blunt cutters.

Hope it's as easy as that to fix!

Dave

Edited By SillyOldDuffer on 10/11/2017 13:27:49

As a Student machinist I am just starting out, My main past time is classic car body work.

but as a student, I have to start some were no????

I am only at the early statges and with out a tutor

Its taken a lot for me to come this far what with even buying a machine, cleaning it, getting the right VFD, fitting that etc etc

I was/am keen to get it cutting in them few jobs I had to take care of around the shop,

now thats ill done, I am here to step up my game and learn where I am going wrong,

hence my questions

Edited By Piero Franchi on 10/11/2017 13:34:04

The thing with smaller lightweight mills is, any deficiencies in technique, wear in the machine, loose gibs, blunt cutters etc etc tend to be massively amplified.

I had a Tom Senior for years and although they are a capable machine, it was possible to get it dancing around the floor if everything was not spot on and locked down prior to taking a decent cut.

You tend to get away with a bit of sloppy technique when the machine weighs a couple of tons.

I know its very hard for you guys to help what with the limited info I am giving,

But I really wanted to know what you lot thought about the stand that I made for the tom senior to sit on.

Do you think its ok with it just sitting on the four bolts???

The stand was made so I can move the mill around if need be, you can just see to solid wheels at the back and on the front there is two lugs that stick out where a separate set of wheels lock in when moving.

I had thought about drilling some bolts into the floor, and locking it down with a set of strap clamps type thing.

do you think it needs it????

I recon the other thing that is not helping me is my own doing.

as a new be, I have been selecting the worn out cutters I have in fear of ruining the good ones.

I thought it best I practiced with the older cutters and incase I made a mistake and broke one

Having now looked at your photo's i don't think the stand is in any way causing your issues........stick a sharp cutter in and have another go   I never had my TS bolted to the floor in over 10 years.

Edited By Alan Waddington 2 on 10/11/2017 17:23:34

Piero

I appreciate you are just starting out, but, there is a wealth of YouTube videos and books out there to aid you.

Your previous posts come over as that you are blind to and refusing to look into speeds and feeds, and the only sufferer from that will be you.

As for worn out cutters, the garbage in, garbage out principle applies. You won't produce good work with worn out cutters, so I don't see any point whatsoever in your position in using them.

To try and tie down what is going wrong in your milling, you need to reduce as many variables as possible. If you mill with a sharp cutter, that is one less variable for producing work that is not of a standard you require.

As for the contraption the TS stands on, (and I say this as a Tom Senior owner), it didn't come from the factory like that, so putting it back to standard removes another variable.

Why do you need to move it around? Do you REALLY need to move it around? If not, find a final position for it, take all that stuff off, and let it sit on its stand like it was designed to.

I still think blunt cutters are the most likely cause but here's a picture of Piero's stand.

Looks good to me and is similar to what I plan to do with my lathe if I reorganise my workshop. I had no intention of strapping it down.

Assuming all four jacking screws take their full share of the weight and the wheels are off the floor, the only thing worrying me is the possibility that loose fitting screws might wobble where they go through the box frame. I've never tried anything like this and am guessing wildly; what do the experts think?

Dave

Thanks for blowing up the photo

Yes the rear wheels are off the ground,

The bolts go through a all threaded sleave (the full width of the box section)

you can just make out the lugs on the left side of the front left adjusting bolt,

as I said, there is a removable front part with two solid casters that aid moving the mill

Edited By Piero Franchi on 10/11/2017 18:06:15