Good supplier of Hex Bolts

[RainbowsParticipant @rainbows]

On the list of projects I have is making a toolpost for a lathe. 1" square shank carbide tooling. Just a basic 4 way toolpost ( or maybe less ways) but I'm struggling to find any suppliers of 12.9 class hex bolts. Google comes up with cap head bolts and I remember seeing on this forum that they weren't very good because swarf got in the socket and became a pain. My understanding is that M10 12.9 hex bolts should atleast theoretically exist.

 

Anyone got a good supplier? Do 12.9 hex bolts even exist?

Edited By Rainbows on 03/09/2015 12:21:27

[RainbowsParticipant @rainbows]

[JasonBModerator @jasonb]

Do you really need 12.9? as they will be in compression I'm sure 8.8 ones will do

Cap heads work fine for me

Edited By JasonB on 03/09/2015 12:25:53

[Bob Brown 1Participant @bobbrown1]

Or split the difference at 10.9 like these **LINK**

Bob

[Nigel McBurney 1Participant @nigelmcburney1]

Suggest turn off the first two threads off the end of the bolt,leaving a plain diameter at just below core diameter ,repeated use of the bolt tends to swell the end of the bolt so when a bolt eventually requires replacement it cannot be unscrewed ,the plain portion may swell a bit but it still allows easy removal. Probably easier and cheaper to find and use 8.8 bolts and replace them a bit more often.

[RainbowsParticipant @rainbows]

Some of the bolts also sandwhich the 3 plates of the toolpost together and another has to hold the toolpost down so they might get put under tension. That said those 10.9 will probably be enough anyway. Interesting about the cap heads. Might swap them out to see which works best.

 

Good tip on the swelling. Will be sure to do that whatever I end up getting.

Edited By Rainbows on 03/09/2015 14:10:12

[Neil WyattModerator @neilwyatt]

I got a batch of M6 and M5 8.8 stainless screws from Screwfix for my toolholders. They have a neat chamfer at the end so I don't have to worry about the swelling that eventually spoiled the M6 ones in my toolpost (admittedly after over a decade). they don't seem to be showing any signs of suffering distortion.

Last batch I bought had 'square' ends though, so it seems to be pot luck what you get.

Neil

[Bob Brown 1Participant @bobbrown1]

My Dickson has this type, note end has the thread machined off but as I have 8 the tool tends to stay in the holder thus avoiding a mushroom end.

Bob

[MuzzerParticipant @muzzer]

For reference:

Fastener properties

Murray

[LambtonParticipant @lambton]

Jason B is quite correct 8.8 bolts will do fine. What you have to take into consideration are the properties of the material and the design of the item the bolt is being screwed into. There is no point in using ultra high tensile bolts unless the mating material has similar strength or if the action of tightening the bolt tends to spring the tool post open.

[Clive FosterParticipant @clivefoster55965]

Fairly ordinary bolts will be fine in this application as the overall forces aren't that high. Bolt up construction from standard plate and bar sections saves a ton of machining and is probably more accurate if you don't have a horizontal mill or shaper to hand. Main thing is to arrange top and bottom plates to be thick enough to prevent any bending when tool is bolted in firmly. Especially when post is removed. Bolt end mushrooming is a fact of life for this sort of thing so its important to remove the first couple of threads as advised by Bob and to regularly pull the bolts to clean up the end. Even the pro gear suffers. Got some Dicksons for £ very reasonable and had to file the mushrooms off about half the bolts in situ to get things good enough to use. Not a pleasant task! Allegedly a piece of 1/8 or so alloy between bolt ends and tool top both prevents mushrooming and gives a better grip at lower torque.

Square heads are less obstructive than hex so if you have a suitable tube spanner machine down the heads to suit. Mr Dickson makes the across flats dimension of his squares same as bolt diameter so, for M10, 3/8 A/F would do just fine. Same size as my T2 Dicksons. Especially if you don't have a suitable tube spanner as Dickson spanners can be purchased or female end of an inexpensive socket adapter would be a good start on making one.

Two way is easier and stiffer than four. Also narrower which can help when working between centres if the tailstock gets in the way. I've almost never loaded a four way with more than two tools so the simpler form doesn't seem a great disadvantage. If you can make more than one post and arrange matters so that they can quickly be interchanged with some sort of alignment gauge or indexing system. Sort of poor boys QC system.

I drew up, but never made, what looked to be a promising QC set up for this sort of thing. Centre stud was to be fairly large diameter and arranged to rotate. Toolholder was threaded in the middle for a large hollow bolt with a castellated end. Centre stud to be cross drilled in alignment with the castellations so a loose tommy bar could be pushed through both. Turning the tommy bar would rotate the stud and wind out the hollow bolt gripping the bar between the castellations and stud cross drilling to clamp the tool post down. Unwinding the hollow bolt a third of a turn or so would release the tommy bar so it could be withdrawn and the tool post lifted off. My plan was to so equip a SouthBend Heavy 10 but a Smart & Brown 1024 arrived at the right price with a Dickson tool post and starter kit (5) of holders so the project was abandoned.

Clive.

 

Edited By Clive Foster on 03/09/2015 16:13:57

[Matt DParticipant @mattd]

12.9 hex bolts do exist; I seem to remember that my Ducati Desmo single has very long ones through the cylinder head/barrel but as they are doubtless specials for these engines this won't help! Could one use softer bolts with a hard stepped block set into the end to reduce the mushrooming? Should be possible in M10.

[RainbowsParticipant @rainbows]

Also on a semi related note does anyone know if this tapping head is complete and suitable for a drill press?

[Neil WyattModerator @neilwyatt]

If I was making a toolpost, i would use the triangular 'Lammas' shape as was popular in the days before QCTPs were readily available.

Details in the 25 year Special – if you can find a copy

Or make from castings, still available from Blackgates when I checked a few months back.

Neil

[RainbowsParticipant @rainbows]

none of those are big enough sadly though I might steal the design

[Clive FosterParticipant @clivefoster55965]

Rainbows

Re Lammas toolpost..

Back in the 1980's my then boss bought a new Boxford ME10 and looked into the Lammas triangular tool post as a potentially better alternative to the standard 4 way. He made a bolt up version and concluded that the device did give better clearance around the the tailstock area. Important with the Boxford as, like all SouthBend derived clones and may other small machines, tailstock travel is short so the (relatively) big 4 way block is intrusive when working at that end. He didn't proceed as he considered the sharp pointy bits problem was even worse than with a fully loaded 4 way. Due to the angles involved you have two sharps in the handling area whilst generally with a four way you only have one.

When I traded up my Pools Special to a Southbend 9"C which came sans tool post I purchased one of the inexpensive 4 way blocks from Chester (2 and bit inches square I think). This proved to be so badly proportioned that it was pretty much impossible to consider loading it with four useable tools. Worked fine with two loaded though. As the SouthBend has a Tee slot in the compound to mount the tool post, rather than the fixed stud more common in Britain, its easy to slide out the tool post after loosening the holding nut. I promptly bought two more of those 4 ways, made up tee nut, stud and nut assemblies for each and used them QC style with two loaded tools in each. This approach worked fine for me through my SouthBend days ending up with 5, larger, four ways on the go for my Heavy 10 although I never really got the accurate reposition issue properly sorted. A gauge was good enuf but would have liked nicer.

Hence I'm convinced that if the accurate, automatic, re-position issue can be cracked rapid change two slot blocks are the way to go. Especially with carbide inserts as the tooling fixes the tip height for you. No shims to muck about with after sharpening.

Clive.

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