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Bovine manure

MichaelG.

#2 for Michael Gs' short and to the point comment.

Any self respecting cross vice needs axis lock screws. Rule 1 when drilling is line up and lock the axes so the job stays put when cutting. Even my ancient and distinctly Early Chinee Sloppy 6" version bought from a Model Engineer exhibition many, many years ago shortly after they first hit the market has locks. Not good locks but they work just well enough that there has never been quite enough impetus to translate the desire to make better into action. Currently sitting on my Fredr'k Pollard 15AY drill. A seriously industrial MT 3 machine which definitely tests their effectiveness with big drills.

Having lived with my sloppy one for mumble mumble years I'd say good locks are more important than good gib adjustment or tight feed screws. Attempting to runa big drill on mine without locks is a bit scary as things go every which way quite significantly until the drill reaches full diameter.

Using an over tight gib screw to lock the slide is a good way to distort the gib. Especially if ordinary pointed screws are used. Proper locks should operate via a relatively large diameter pusher to apply force over a reasonable flat area.

Frankly trade descriptions act applies.

Clive.

Edited By Clive Foster on 17/01/2019 19:08:36

Think a Kipp / Bristol style handle as suggested by Mike may be overkill. My locks have simple oval flat head thumb screws maybe 3/4" and a bit across working via some coarse Chinee thread sort of 1/4" diameter. I think a similar device with a fine thread of similar diameter would be more than satisfactory.

Has the advantage that you can ensure there is always clearance. I've broken my share of Kipp / Bristol handles and bent the odd tommy bar simply through forgetting that they were in the way when adjusting something and neglecting to adjust them out of harms way.

Clive.

I would say it is perfectly normal to have a row of gib screws and for one to be say a cap head and be used for locking. Many gibs only have 3 screws. Since locking implies the movement provided by gibs is not in use there is no need for the screws not to be dual function.

It is no different from the description of lathes having both metric and imperial screwcutting capability. They are not independent – they use the same leadscrew and many of the gears in common.

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Mine [a hand-me-down from a well-meaning friend] was good for the Charity Shop

Having spent several years tripping over it … I finally got round to donating it.

MichaelG.

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https://www.model-engineer.co.uk/forums/postings.asp?th=117044

Edited By Michael Gilligan on 18/01/2019 10:38:01

I bought one of these cross vices several years ago; on examination it was so badly made that I returned it next day.

The one in the picture looks relatively good and it should be a simple matter to install locks to the slides.

Bill P, How do you adjust the bottom slide as there only appears to be one adjusting screw – or is that what they call a "Slide lock". My Old Warco mill drill doesn't have a "slide lock" as such, you just over tighten one gib screw to lock it, so that method has been around for years on 'simple' machines.

Bill, as others have said the existing grub screws with locknuts are intended, or should be, to locate and set the gib to give the required sliding fit to allow axis movement. An additional central, to the length of the gib, screw without a locknut should be used for applying an additional locking force to prevent movement of the axis. The seller is trying to convince you that what they are selling is correct in having a locking feature that is doesn't have. Modify yourself or return if the selling blurb say's it has locking.

Hmmm. I detect a faint trace of hyperbole…

I nearly bought one when I was about 17, but someone told me then that they weren't very good. I didn't at first think they knew what they were talking about, but I kept on asking everybody if anybody knew anybody else who'd ever used any one of these successfully to do anything, and nobody replied.

I think I must've lost interest, or found another way to do whatever it was in my tiny mind at the time – 'twas a long time back.

Proper slide locking screws may be interspersed in the row between gib adjustment screws, but are longer and don't carry a locknut. Gib adj. screws might be grubscrews, but locking screws usually have a cap or head. I'd think it's probably a Trades Descriptions offence to describe an adjuster as a lockscrew, for the very good reason the OP gives about messing up a carefully-worked adjustment.

The slides in the crossvice in the photo still look rather short for milling, and I can't see that the moving vice-jaw has much parallel guidance – so I can't really visualise how vice-like its grip really is.

Looks like I'm on my own as being respectably satisfied with my cross vice. As mentioned earlier mine is an older 6" version which appears to be bit more substantial than the later types and has a rod type guide for the moving jaw.

Yes the screws are sloppy and the gibs not wonderfully precise but it is what it is. An effective device for moving parts around to bring them into alignment with the drill before making a hole in the right (we hope) place. With the thumb screw locks tightened up it holds quite securely enough for any sane job.

OK its not a proper X-Y table with precision, graduated screws. But at the price I paid, £60 – £70 from memory many years ago, any such expectations would have been totally unreasonable. I was a little disappointed by the general fit and slop but it worked. One thing I did have to do was swop the hopeless plain, smooth, flat vice jaws for a pair of prismatic type. NuTool brand so no longer around but no doubt similar can still be found. One horizontal Vee groove and three vertical ones of different sizes. Turned a dubious in the extreme device into something eminently useable within its limitations.

Proper co-ordinate drilling gets done on the Bridgeport which has a 3 axis glass scale DRO set fitted.

Here is a job we did this afternoon.

Hollow stainless steel oil union around 25 mm long with 27 mm AF hex and M23 x 1.5 external threads held in a 5C collet about to receive an M16 x 1.5 through tap. Pollard No 4 tapping head driven by Fredr'k Pollard 15 AY drill put the tap through "just like that". Two done in a couple or three minutes. Cross vice locked up by thumb screws in both axes didn't even blink.

The vice pretty much never comes off the big 15 AY drill. Maybe one or twice a year. Normal configuration is with a flat "improved wood" table held on via a wide batten underneath.

Ideal for sheet or many smaller components that can be held down by a few strategically placed twin thread screws zapped in with a battery drill. Or clamp to the overhanging sides with G, tool or friction type trigger clamp. Have a smaller one too for similar work. Easily removed when I want to use the naked vice.

The plate shown is probably past its best but I have a stack of old kitchen furnishing panels up in the shop attic to make a new one from.

Clive.

Edited By Clive Foster on 18/01/2019 22:15:06

Bill.

Definitely overthinking this. Fit some lock screws and she'll be fine. Use a flat, angle ended, pusher between screw and gib GHT style to give an even force over a reasonable area. The pointed end on a gib adjustment screw concentrates the force rather ineffectively over a small area, deforms the receiving dimple in the gib and risks bending the gib itself which isn't exactly helpful.

I've had to deal with the results of such practices when refurbishing a lathe cross-slide gib that simply wouldn't adjust any sense. The bits supplied weren't pretty. It got a new, straight gib and the full GHT treatment after a Clive Super-scrub clean. Recipient said some really nice things about the results and now has a seriously overinflated view of my abilities.

Nip the gibs up a bit tight so movement is on the stiff side and accept that you will be positioning by eye. Co-ordinate drilling is probably possible if you fit some cheap readout on stick scales but, realistically, that is moving into taking the porker to the beautician territory.

If you can, do make or buy a set of proper V groove prismatic vice jaws like mine. Vastly better than the style you have and much more tolerant of grabbing uneven parts. Despite the relatively small contact areas I've not had an issues with marking work.

I really don't like the very thick base. Although its theoretically nice to have the handle clear of the table where-ever its put in practice a right size cross vice for the machine will pretty much invariably end up with the handle overhanging the table anyway. The overthick base and your, essential, block of wood are costing you about 2 inches of valuable drill clearance.

Last thing. For my peace of mind, please junk the Mole / Vice grip lever clamps and bolt it down. They can relax under vibration and self release like a fly off handbrake. Seen that happen. By the grace of God just major fright time for the person concerned not injury. Those clamps are great when used as intended in single grip mode. Clamp, do the job release, re-clamp for next job. So you know they are tight "right now" before starting. Leaving to hold hoping it will be fine for long periods is just too chancy.

Clive.