‘STIFF’ Compound Slide

[kevian64Participant @kevian64]

Hi, having recently bought my 1st ‘proper’ lathe an ML7 I’ve just started making chips. I’ve been watching a guy (Steven Jordan I think) on YouTube and following his idea of grinding 3mm off the back of a toolpost holder so I can use 12mm stock.

Its my 1st machining since 1980 and loving it. I’ve noticed that the compound slides movement is VERY stiff compared to that of the cross slide. Is this normal or should it be just as ‘smooth/easy’?

 

Cheers Kev

[Grizzly bearParticipant @grizzlybear]

Hi,

This might sound stupid, have you tried to adjust it?

Three grub screws with lock nuts.

Good luck……….

[BazyleParticipant @bazyle]

hello, welcome to the forum. We have better advice on here than other places on the ‘net which can sometimes be a bit dubious. “stock” is the material you put in the chuck to make things out of. Do you mean tool? If so stop watching this idiot on youtube. You only need 1/4 in tools, or perhaps up to 3/8 on a Myford. Do not grind bits off your lathe until you have several years experience in using it and ask us first.

[Bazyle]

On Bazyle Said:

If so stop watching this idiot on youtube.

Spot on there!  I used to watch some of his videos – just to see how <b>not</b> to do it.🙂   My impression of his channel was that he reviewed anything, that gained him brownie points, from cheap chinese trash merchants.  Glowing reviews, of anything they would send him free of charge, even if the quality was at the cheapest and nastiest end of the market.

 

[Charles LamontParticipant @charleslamont71117]

With something stiff on a newly acquired lathe I would be inclined to strip it down and investigate.

Strip, clean, examine, adjust and reassemble. With the feedscrew and its bracket removed, you should adjust the topside gib screws so that you can just move the slide backwards and forwards smoothly without tight spots. When refitting the bracket, wind the feedscrew fully home in its nut before tightening the bracket mounting screws.

[Nigel Graham 2Participant @nigelgraham2]

Yes, the slides should move easily without shake, but not too freely.

Seems a bit odd that the top slide should be so stiff.

Possibly the last owner tightened it for some specific purpose of his (I can’t think / dread to think what) and forgot to reset it.

Or lubricated it with grease and that has hardened off! (Use only oil.)

….

“grinding the back of a tool-holder…” EH? I am not clear what is meant here but this suggests a Quick-Change Tool-Post (QCTP) system, which has three basic parts:

1) The body with built-in clamp that you fit on the top-slide, in place of the simple clamp originally fitted.

2) The tool-holder; a block of rectangular channel section fitted with various clamping and adjusting screws, and which clamps to the body. You need a set of these, at least four to start with. You can add more later.

3) The tool itself, either an HSS tool usually of square-section, a carbide-tip shank or the parting-off blade carrier; which is held in one of the tool-holders.

All of these, certainly the better-quality ones, are precision-made to co-operate to give you repeatable, reliable tool-changing. The lowest-cost ones available though “our” suppliers or other recognised retailers, rather than dubious on-line supermarkets, are usually fine for most of our purposes, though the most basic type does have some drawbacks.

I treated my Myford ML7 to a Myford-branded QCTP and find it eminently satisfactory, so please do as we do: buy tools appropriate to the lathe and its fittings. Don’t try to copy bodges seen on t’Net.

 

I think I have occasionally seen admissions on this site, to having machined the underside – not the rear – of a insert-tool shank to fit a particular QCTP. That though is an exception, carried out properly, on a milling-machine, by an experienced machinist; and to modify the tool shank itself, not the tool-holders.

The most likely reason is having acquired some second-hand tooling, modifying it to suit the machine.

 

Taking a grinder to any of the working faces on any of those elements, ruins it by removing its whole point!

Others have said don’t do it – I agree – but your post reads as if you’ve already been and gone and done it. Oh dear….

I rarely look at Ewe-Tyoob but notice there are one or two contributors respected by others here; either for model-engineering and related activities directly relevant to us, or large-scale engineering of interest for its own sake. However, you also sometimes see on this forum warnings about bad workshop habits, poor techniques, sometimes dangerous practices, depicted in many videos.

[Author]

Posts