Need something milling

[Brad93]

Ordinary steel will do, if you’re yanking on it hard enough to bend ms then you’ve broke the cast iron!
My old pops repaired a lot of compound slides with pulled tool post studs.
Mig brazing worked the best but I’m going off topic..

What did your old man do Clive?

sorry to go off topic

 

[Brad93]

Ordinary steel will do, if you’re yanking on it hard enough to bend ms then you’ve broke the cast iron!
My old pops repaired a lot of compound slides with pulled tool post studs.
Mig brazing worked the best but I’m going off topic..

I’ve got the perfect bit of steel in that case.

 

[rory1]

Can’t help with the machining cos I’m busy on at the moment but I would agree with pressbrake - it will be fine out of mild

 

[Paul in Wiltshire]

Quick question, you don’t know what the different sizes of hex are on the spline keys are do you? The hex on mine is 12mm across flats.

I want to order a bigger key (Assuming the bigger sizes use bigger hex so I can make a custom nut so I can take the toolpost off with the same handle.

Don’t know I’m afraid. My set probably won’t arrive until early July. For the registration pin, I’ll probably turn my own, 5.6 mm one end, probably 1/4 inch on the other as I have imperial reamers. Tool post is hardened > 45 RC, so probably best not to try reaming it out with HSS.

 

[Brad93]

Don’t know I’m afraid. My set probably won’t arrive until early July. For the registration pin, I’ll probably turn my own, 5.6 mm one end, probably 1/4 inch on the other as I have imperial reamers. Tool post is hardened > 45 RC, so probably best not to try reaming it out with HSS.

I was thinking carbide to be honest.
The toolpost itself is hardened, but the base on mine, the two holes, have inserts in them. Not sure if they’re hard. Need to get a set of those hardness testing files.

 

[ukracer]

no problem

Thank God for that I was feeling I ought to offer. But was put off by the mention of tough...

I have only done a bit of work with steel on my Bodgeport most of it has been Aluminium....I feel ok to mess with my own stuff but messing up someone elses steel gives me the collywobbles..

 

[Agroshield]

Before you install the new toolpost, perhaps give the compound a quick rub on a surface plate to make sure it is flat and that the wings of the slot have not pulled upwards from prior abuse. Similarly, while your fingers, clothing, steering wheel, dog and Micky are still blue, rub the bottom of the new toolpost. Stone the underside of the wings to deburr.

The top of the new bit of steel needs to be a little below the top of the compound when everything is tight. It is not good if it bottoms out on the underside of the toolpost. Same as a D1 chuck fitting: 1 thou' feeler gauge should go in.

Did you consider a 7/32" dowel pin?

Or make your own on a surface grinder?

 

[Hood]

I was thinking carbide to be honest.
The toolpost itself is hardened, but the base on mine, the two holes, have inserts in them. Not sure if they’re hard. Need to get a set of those hardness testing files.

Would a 7/32 dowel not be close enough to 5.6mm for this purpose?
https://www.boneham.co.uk/dowel-pin...al-3-inch-solid-dowel-pin-to-bs1804-limits-dp


Edit

LOL looks like @Agroshield thought the same

 

[Agroshield]

Drill blank:

https://www.zoro.co.uk/shop/cutting-tools/hss-drill-blanks-/39150506?6292=5.6mm

Would advise you make the piece from hot rolled. I have just made a 20" long stick of T-nut stock from cold rolled and it bowed 5mm upwards in the middle.

 

[RichardM]

Should the location pin be sacrificial, ie made of something soft which will shear?

 

[Hood]

Should the location pin be sacrificial, ie made of something soft which will shear?

That would be my worry with a location pin if too hard. On my toolpost on the manual lathe I thought about making a pin but then decided it is better that the toolpost will swivel if I do something stupid which I have done once or twice

On my CNC lathe the turret I made has tapered locating dowels as is common with a lot of CNC machines. I however just use them for alignment, torque up the holding bolts and then remove the dowels, that way if I have a crash the dowels are not deforming the holes and I can just slacken the holding bolts, insert the tapered dowels and then tighten the bolts again and then remove the dowels.

 

[grim_d]

Why are you making a new tee Brad? Just for the dowel?

Don't waste your time, under normal use the toolpost won't move and when you have a bit of a crash it's far better that the toolpost moves rather than breaking the compound.

Plus it would mean swiveling the compound If you wanted to rotate it at all...what a hassle.

 

[Brad93]

Yes thinking about it the pin should be mild steel.

@grim_d the whole idea of the multifix toolpost is that it doesn’t rotate.
The outer collar locks in 40 different positions.
360° / 40 = 9° degrees per index.

5 slots is 45 degrees, 10 is 90 degrees etc

 

[Brad93]

Thank God for that I was feeling I ought to offer. But was put off by the mention of tough...

I have only done a bit of work with steel on my Bodgeport most of it has been Aluminium....I feel ok to mess with my own stuff but messing up someone elses steel gives me the collywobbles..

I’ve got a big 20”x20” square of this plate. Wouldn’t be an issue.

 

[grim_d]

Yes thinking about it the pin should be mild steel.

@grim_d the whole idea of the multifix toolpost is that it doesn’t rotate.
The outer collar locks in 40 different positions.
360° / 40 = 9° degrees per index.

5 slots is 45 degrees, 10 is 90 degrees etc

Yeah, but what when you want to go between one of those 9 degrees? Which happens fairly often such as when you've moved the compound to a specific angle and none of your tooling indexes properly anymore or there's a clearance issue, then when you move it back, is the scale on the compound accurate enough for your parting blade to be perpendicular, far easier to bump the toolpost than the compound.

I've been using mine for about 4 years now, not once would I have benefitted from the pin.

I can see the benefits for cnc like @Hood , but even he removes them once aligned.

 

[Brad93]

My compound stays at 30 degrees, rarely move it unless cutting a taper

 

[grim_d]

1 example of many.

It's simply not necessary.

 

[Paul in Wiltshire]

1 example of many.

It's simply not necessary.

There are two holes in the post, one offset by 15 degrees. By placing the pin in the 15 degree hole instead of the 0 degree hole you now have 80 permutations, drill an alternative pin position in the cross slide and you can get 80 more.

One of the main reasons for switching to multifix for me is repeatability with the DRO. If you have a locating pin you can be sure that the post is in the same position and can ensure that, for example, parting off tools run perpendicular to the lathe axis. The tool post is designed so that you can use a long pin that can be extracted from the top. That way you can pull the pin and adjust to any angle you want if needed. Then once you have finished, return to post to the preset position knowing that the tool offsets in your DRO are still valid.

As for the debate of hard vs. soft pin, neither will shear in a crash, I wouldn’t think there is much merit in a super hard pin, but harder materials are easier to machine to precise tolerances, I’ll probably use silver steel or EN24T. Somebody suggested an imperial equivalent of 5.6mm, that equivalent is .04mm smaller, in my experience that will be a sloppy fit. That 0.04mm of slop will be amplified at the tool cutting edge to a potential error of about 0.1mm. Fine for a lot of things, but if you are pursuing repeatability and accuracy you might not want that.
YMMV

 

[grim_d]

@Paul in Wiltshire

That's why I was asking why. I suspect Brad will be concerned with rigidity or movement? In which case it's not necessary, I know from experience.

Dealing with the pin seems a great deal of hassle for the average home gamer.

Is it a create toolpost you have? What is the repeatability like? Ive never measured because it's largely irrelevant to me, can't imagine it's as good as a Swiss?

What if you shift the compound? Don't you need to reset your offsets? How do you index that? genuine question. Or are you solid toolpost mount?

In order to access the pin holes whilst it's nipped up you'd need to leave the top shield off no? Else it be all the wobbles.

 

[Agroshield]

There are two holes in the post, one offset by 15 degrees....

...The tool post is designed so that you can use a long pin that can be extracted from the top. That way you can pull the pin and adjust to any angle you want if needed. Then once you have finished, return to post to the preset position knowing that the tool offsets in your DRO are still valid....

...That 0.04mm of slop will be amplified at the tool cutting edge to a potential error of about 0.1mm. Fine for a lot of things, but if you are pursuing repeatability and accuracy you might not want that....

.

May I make a few observations?

The 15 degree pin offset seems a little bizarre given that the post indexes at 9 degrees. This effectively means you have a 3 (or 6) degree difference at the tool. Were it 30 degrees, it would have some logic to it.

Presumably one of the 15 degree holes is synchronised to/aligned with one of the 9 degree positions. It's probably important that on initial set up of the post that you choose the correct one.

When you pull the pin from the top, do you need to loosen the main securing nut to adjust the angle? If so, then a low-and-wide-T-nut carrier that Brad wants to make would also have to be secured against sliding in its slot to assure repeatability.

A single pin will not assure repeatability anyway as the post could pivot on the pin, taking up any slop in the central securing bolt hole.

If you are going to worry over the dowel pin size, you also need to assure yourself of the tolerance to which both the 5.6mm hole in the toolpost itself is formed and the new hole in the securing-T-nut. At best, the person making it will buy a 'standard' 5.6mm reamer.

I can cut to a precise tolerance of plus or minus 1.0000" all day long, soft or hard, toolpost pin or no. If you need more precision in your tolerance, for a little extra cash I can do +/- 1.00000" for you.