Member postings for DiogenesII

Nick, as a matter of interest, do your Clamping & Forcing Screws 5 & 6 actually conform to the last illustration? ..only asking because mine are the opposite way round to that..

Hi Jamie

When you check the alignment again, make sure that the saddle is correctly adjusted to allow free movement along the bed, but without free-play - this is critical to accuracy on the Hobbymat as it has a round bed. Use a centre in the tailstock, and lock both the tailstock and the tailstock quill, as well as the slides.

As Jason suggests, looseness of the headstock bearings will cause this issue - if you have run it for 1/2 hour since refitting them, I'd check this first - they do tend to settle in a after a little running..

Old Mart got there first +1 for impact driver.

Similar to here, at 12 minutes in - different shaped part, of course, but same principle.

https://www.youtube.com/watch?v=wUSgS7FHIds

apologies, tried to embed but couldn't find sizing option..

I think Nick has it.. Hot forging in a die using a mandrel of the correct shape?

..Broached? ..is there a wedge-slot at the back? ..it looks like one of those processes that sprang from their gun industry..

GLR Kennions still supply in 3/4 & 1" widths..

Hi Chris. The standard milling table that Hobbvymat supplied is aluminium alloy, and the vise bolts length-wise to it, i.e. jaws parallel to slots.

If you want (or need) to use the vise with the jaws in the other orientation, it can be bolted directly to the topslide - using one mounting hole beneath the toolpost, and the other is the one between the toolpost and the back of the slide (if you wondered what it was for.. it's usually plugged with a slotted grubscrew) ..be mindful of the length of the bolts used - there's very little clearance between the upper & lower parts of the slide, and also, be gentle when tightening either the vise or the toolpost when fitting - the standard bolts have a shear groove in them to prevent overtightening (and bowing or warping the topslide)

Ha, that brings back the days of the Colourtune! ..seriously though, that's a very clean & consistent burn - do you know what fuel it's running on in the video?

Thanks for the information Peter, I suspected that the answer would lie in the DIN system somewhere - the smaller Hobbymat/Prazi/Saupe Sohn machines with which I am more familiar never seem to have been supplied with draw-in collets and instead used a small spindle-nose chuck taking DIN 6343 F17 125E collets..

Well. Clearly a vexed question.. anyone?

All of this was a completely unknown world to me until the 'Viper thread.. now I find I'm really looking forward to watching things develop, many thanks all.

Well reminded, Bazyle -

The 20T gear carrier comprises a simple stepped cylinder 21.7mm long. The central bore is 8mm (ream if possible).

The larger part of the component has a diameter of c.19.98mm (light push fit for a 20mm bore) and is 10.2mm long. It has 4mm wide key slot, 2.6mm deep (which could be formed by hacksaw and file if necessary - aim for perfection, but settle for adequate - it doesn't run at high speed or take a great load, and mates with a moulded component).

The reduced part that carries the 20T gear is c.13.6 to 13.7mm in diameter (mine is firmly fixed and I'm not going to prise it off!), the dimension isn't critical as the gear is permanently affixed by pressing onto the carrier, so make matched components - aim for a fit that requires say, light vise- rather than finger- pressure, but without "stretching" the gear too much - again, a tiny inaccuracy here isn't the end of the world as running clearance is established whilst setting up the gear train in any case. If one could arrange a parallel knurl, this would be exactly the job for which that process is intended, but failing that any knurl would probably do.. An adhesive might do, but I'm not sure that all are effective on plastics - advice welcome!

The gear should be 11mm thick, leaving 0.5mm of the carrier projecting beyond the face to provide axial clearance for the gear once the carrier is secured to the stud with it's screw & washer.

Both outer edges and the ends of the internal bore should be generously chamfered, for ease of fitting, to reduce friction, and to allow the ingress of oil.

In order to cut the blanks for any of these 1Mod gears, simply take the number of teeth required and add 2 to arrive at the finished diameter in mm - thus 30T = 32mm, 60T=62mm, 100T=102mm etc. With the exception of the 20, which is 11mm, all the others are 10mm thick.

I'd get a piece of Leaded ("free-machining" Bright Mild Steel Round Bar (EN1APb) for this job (I note the standard item is "soft", probably to save wear on the studs), and it's an exceptionally pleasing material to work with.

Edited By DiogenesII on 31/12/2019 13:38:05

The gears appear to be 1.0 MOD, are 10mm thick, and have a 20mm bore which is slotted to accommodate a 4mm key.

(50T gear=52mm OD, 60T=62mm, 70T=72mm, = 1mm of PD per tooth plus the addendum (= to mod) on each side).

I can't establish the pressure angle exactly from my worn examples, but 20 degrees seems the most likely to me - it's a "modern" metric machine made in Europe, for those not familiar with it - additional informed comment or confirmation would be very welcome, here.. (..although if you are going to get a set printed, it's rather immaterial in any case, as long as they are all the same.).

You will need; 20, 30, 35, 40, 50, 55, two 60's, 65, 70, 75, and 100, if you want every option listed on the plate. Even for common metric threads you will still need 30, 35, 40, 50, two 60's, 70, 75 & 100. A 20 is "nice-to-have" for a fine finishing feed.

I'm not familiar with the mini-lathe change-wheel sets, but do be aware that the Hobbymat uses a 1mm pitch leadscrew, which I think is finer than that fitted to ?most mini-lathes and therefore the ratio between headstock-spindle-turns versus amount-the-carriage-advances will be different.. might be worth doing the maths/checking the tables before buying any gears, just to make sure that you will be able to achieve the ratios that you need.

Good luck!

Dependent on your calipers, it may be that you may just need to reset the origin.. ..not all have this facility, but some have an "origin" button, and others have a small hole to access the reset switch with a paperclip or similar..

It's just a reset for the original "0" calibration..

Jon, ...it's also not uncommon for that sort of thing to get separated at auctions or estate sales, where neither vendor, auctioneer, or sometimes even purchaser actually knows what any of the lots actually are..

Andrew - ..just food for thought, but having slept on the idea, might it be easier to form a shallow cone by starting with a plain cylinder (and removing a long thin fillet) rather than a flat sheet? ..you'd have a bit more control of the metal..

Just for the sake of "completeness" ..the MR16 also has a pair of opposing grooves on the "neck" above the pins which are provided for retention by a clip on some types of holders.. but like others have noted, it'll be easier to contrive a blob of something sticky..

..knew I should have bought them.. ..next time you see them they'll be £150..

Not on familiar territory here, but could those splines be ?Colchester-ish?

The smallest is stamped "30B", didn't manage to successfully count the largest..

**LINK**

Apologies if this is a clumsy link, just thought they might be of interest to someone..