Cutting T slots

This topic has 9 replies, 6 voices, and was last updated 22 December 2014 at 00:49 by Robin Graham.

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13 October 2014 at 22:55 #7337
Robin Graham
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@robingraham42208
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13 October 2014 at 22:55 #166487
Robin Graham
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@robingraham42208
This is actually a cunningly diguised "Which mill should I buy" thread. If I wanted to cut a T slot in mild steel say 15mm throat, 25mm wide by 12mm high in the recess, would I have any chance on a machine like an X3? Or would I need a Bridgeport, or something even bigger? I don't necessarily need to do this, just trying to get a feel for what is possible.

Regards Rob
14 October 2014 at 00:06 #166493
Paul Lousick
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@paullousick59116
Hi Rob, I have an SX3 mill which could cut the T slot.

The standard cutter which I use is a 30mm end mill with carbide inserts which handles most jobs easily. This is a great little machine but bigger is always better. Your choice of mill depends on what you want to machine. The piece you are machining has to be able to be mounted on the mill with clearance for the cutter. I like my SX3 but if I had a bigger workshop and more $, would prefer a Bridgeport or similar.

Regards, Paul.
14 October 2014 at 00:20 #166494
IanT
Participant
@iant
I understand the purpose of your cunningly disguised question Rob – I just think it's probably the wrong one to ask.

Just about any mill should be capable of cutting a T-slot 15mm x 25mm x 12mm high in mild steel. Of course, most smaller machines will never do it in a single pass (or even in just a few passes come to that) and depending how rigid the set-up is – will also depend on the final finish and actual accuracy of the T-slot.

It's a bit like asking what size of lathe do I need to cut 2" diameter mild steel down to 1" diameter – and the first question I'd have is "how many passes do you want to make?" e.g. what depth of cut are we talking about?). Because I could do this on my EW or on the Colchester I first learned on but I know for sure which one would do the job the fastest. In other words, I can machine most things to size (provided it fits the machine's work envelope) but it might take me a very long time on a smaller machine versus a larger one – and the end result might not be so good because of lack of rigidity etc.

So my cunningly disguised answer (and I don't have an X3 – and it's many years since I've used a Bridgeport) is that (provided the work will fit the mill's table) an X3 should be able to mill this T-slot but I wouldn't expect it to be able to do it as fast as a larger machine. So if you have this size of T-slot to machine very regularly – then get a bigger mill (it will be quicker and more rigid) but if this is going to be a once in a 'Blue Moon' need – and the rest of the time you are normally working on smaller jobs – then I'm sure the X3 would be just fine.

In other words – tell us what you will normally use this mill for – what type and size of work – and whether you are going into full production – or just doing the odd job in your spare time. You might get some more informed advice.

Regards,

IanT
14 October 2014 at 09:06 #166508
Mick Henshall
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@mickhenshall99321
Done on a Warco WM 14, 3/4 by 3/8", done in one pass taking feed very steady, material 4" bms & plenty off cutting fluid with frequent stops to clear swarf, around 500 rpm adjusted till it sounded right,this was my first attempt at a t slot and pleased with it, the WM14 is a sturdy piece of kit and done everything I wanted without complaint

Mick H
14 October 2014 at 09:10 #166509
Mick Henshall
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@mickhenshall99321
Heres other pic – Mick H
14 October 2014 at 10:58 #166519
Neil Wyatt
Moderator
@neilwyatt
My mini-lathe cut t-slots the same size as Mick's and that's using a vertical slide so an X3 should do the job with ease.

Probably not the answer you want to hear

Neil
14 October 2014 at 11:26 #166523
John Burridge
Participant
@johnburridge26484
The other way is or was cutting Tee-Slots on a shaper or planer,only simple tools are required.
21 December 2014 at 21:14 #173226
Robin Graham
Participant
@robingraham42208
Sorry to have left this thread orphaned for so long – real and unreal (Xmas panto) life intervened. I have been mulling on your replies, for which thanks, though.

IanT – I think you are right that I asked the wrong question. What I was trying to do was evade the inevitable (and wholly reasonable) 'it depends what you want to do' response to 'which mill/lathe' questions, which I would be hard pressed to answer. I don't build modelsas such – what I do is just 'make stuff', sometimes for my own satisfaction, sometimes for beer tokens.

Mick – thanks for your pic of a T-slot cut on a WM14. I'm amazed I have to say. I have a WM14 and would not have thought it remotely possible – likewise, Neil, I wouldn't have thought it possible on a mini-lathe + vertical slide. So again the wrong question and therefore not the answer I wanted!

Truth is that I want the biggest and most versatile (not flexible, as the marketing people sometimes write!) machine I can afford and fit into my newly acquired cellar workshop. Budget is about 3k, size limitation is on height – the vaulted cellar roof is only 2020mm at its highest point. In the Warco range I'm thinking WM18, VMC turret or GH universal.

To give some context, I have recently bought a 500kg lathe (axminster eqivalent of Chester Crusader I think). Previously I had only a Proxxon PD400, which is roughly the size and weight of a mini-lathe. So far I haven't done anything on the new machine that I couldn't have done on the Proxxon, but it's just so much quicker, easier and less stressful (both for me and the lathe) on the bigger machine. I guess I'm looking for a similar improvement with milling. I've used lathes of the same sort of weight as my new one at work, so had some idea of what to expect, but I have almost zero experience with heavier millers, so don't know which way to go. Perhaps it doesn't matter – maybe any of the machines on my short list would be fine. Probably I need to go and look at them in the flesh as it were.

Thanks again for your input,

Regards, and good Yuletide to you all, Robin.
22 December 2014 at 00:49 #173241
Robin Graham
Participant
@robingraham42208
Thanks, John / Bogstandard, the 836 seem to tick all the boxes – missed it in my researches. I just hate the Chester website so don't follow up on their stuff. I'll PM when the mead wears off – it's Solstice. Someone's got to wake the sun up!

Regards Robin.
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