Topslide question

Hi,

if I was to buy a quick change toolpost that I’m interested in, would this bottom washer with the 3 screws have to be removed as well.

I ask this because the screw nearest the camera will not budge, there is hardly any slot for a screwdriver, I’ve tried a few times.

if it has to be removed, any ideas how I’d shift it.

thanks

chris m….

Yes! Can you file a wider slot? Or drill the head of the screw off. The "washer" is a ratchet cam for the previous toolpost.

Try using an Impact driver.

Emgee

It might help to press out the main stud.

Or next best thing to an impact driver - put a well-fitting screwdriver in the slot and give it a sharp tap with a hammer. Sometimes that's enough to jar screws free.

Rob

If you have the tool holder that matches the ratchet, then I recommend that you retain the original set up. QCTP s are fine, but they are not all good news! I have a QCTP system which I use, but it isn't as rigid as the original set up. I revert back to the old system when I want to rough out a piece of work and when I want a good finish with honed HSS.

They also cost a fortune, you will need lots of holders if you want the benefit of a quick change system. If you are a relative beginner, there are more important things that you could spend the cash on, a QCTP system is not one of them.

I did the same as you wish to do and I regret it! I could have spent the cash on far more essential things. If you have plenty of money to spend on your hobby the fine go ahead and get a QCTP, otherwise think about what you really need right now.

If you haven't already, you could try using one of the interchangeable screwdriver bits. They have parallel tips as apposed to a regular screwdriver tip that's tapered that might induce "cam out". However, do bear in mind, the ISB's tend to be a bit brittle.

Also, another vote for the impact driver. Good luck.

+1 : Slotted screws are a pain in the rear end because it's important to use the right-sized screwdriver, Anything less than a blade that fits accurately into the slot, width, length and depth, risks chewing the screw-head so badly it has to be drilled out. A few things to try, maybe in combination:

• Build a dam around the head with modelling clay or bathroom sealant and flood the top of the screw with penetrating oil. Leave it for at least 24 hours and try the well-fitting screw-driver. Don't force it: there's a high-risk of mangling the slot or shearing the screw. If it doesn't move with moderate force, re-soak it, and repeat.
• Heat is good at breaking corroded and gummed up threads. Heat and cool the area several times with a blowlamp. Don't overdo the heat! If still tight after a few cycles, try penetrating oil again
• If still seriously stuck move to an impact driver or screw-extractor. Impact drivers force the blade into the slot whilst applying a powerful undo shock turn. Be careful not the break the casting! Screw-extractors have a left-hand thread that screws into a pilot hole drilled into the axis of the stuck screw: the harder it's turned, the tighter it grips except there is a risk it will strip the screw.

If the screw doesn't come out without fuss, I really don't recommend doing this just to fit a QCTP. At this stage I'd bet the farm a QCTP isn't needed!!! Later maybe, but it's not smart this early to get embroiled in a tricky screw-removal. Be aware the cross-slide is a brittle casting, not immensely strong, and the more brutal stuck-screw methods risk breaking it. They're hard to replace or repair, and without one the lathe is almost useless...

Dave

All that you can't do without a topslide is short tapers and screw cutting. Even that can be done, just not as well. Topslide is in the way 90% of the time, Tubal Cain even designed a Gibraltar tool post to replace it on Myford S7

Not that I advocate breaking the one you've got of course

Edited By duncan webster on 09/07/2022 20:22:18

'Can't do screw cutting'?

Tony

Would agree that the top-slide is not a necessity. Nice to have but decreases rigidity. Quite easy to add a cross-slide tool-post and screw cutting is probably easier as you don't have to faff about with angles or add a bit to cut on one side of the tool. Increased stiffness in the setup makes straight in-feed simple.

This is the cross-slide tool-post I made for my WM250.

As to the problem screws: Remove the top-slide and work on the bench or hold it in the vice. Don't try to do it in-situ. If you have, or can borrow, an electric impact driver with a suitable bit removal should be straightforward.

John

Edited By Journeyman on 09/07/2022 21:18:39

I didn't say you couldn't, I just find it better to feed down the flank, others are happy to go straight in. Both ways work

I'm not familiar with that type, but I would remove the moving part of the topslide and see if the toolpost bolt could be removed from underneath. The three screws may also hold the bolt in as well as the ratchet in which case the use of a good fitting inpact screwdriver would be the best way. Trouble is that bolt projecting makes getting an impact screwdriver bit to fit may be a problem, not many are long enough to clear easily.

drill the head off the rest often unscrews easily if it don't drill it all out but only if you are brave

Oh dear, what was I thinking? Sorry about that, I exaggerated the problem. But nonetheless painful if the part is accidentality broken.

Dave

The only reason other than vanity for a homeshop lathe to have a QCTP is if you are using hss tooling. Every time it is sharpened, it gets a little lower and the adjustable height is then useful.

If it's a Myford, the three screws only hold the ratchet

Roy

Oh I don’t know🤔

Tony

the other side of that is the QCTP and the 14 tool holders are the best value tooling I've bought for use on and around the mill and lathe. My opinion is that a QCTP should be high up the list of necessities for anyone who intends to actually use the machine.

Would it be possible to bore a recess in the underside of the QCTP so that it sits over the ratchet and down onto the base. Or, perhaps you could make a “washer” with a central hole to fit over the ratchet which is the same thickness as the ratchet forming a slightly higher base ?