Made a pair of basic V blocks.

[Ron LadenParticipant @ronladen17547]

[Ron LadenParticipant @ronladen17547]

A friend asked if I can make a new steel shaft for a piece of old farm equipment he is renovating, its not too big with turned ends and various bits of milling along the length.

I thought for the milling a set up on a pair of V blocks would be good but I dont have any but I did have a piece of 45mm square cast iron so I thought I would give making a pair of blocks a try.

It went ok and I,m quite pleased with how they turned out, now before I get jumped on – no they are not hardened steel, no they are not precision ground and they are not sized and matched to within a tenth of a gnats wotsit.

They are reasonably accurate though and as good as I could get from milling a lump of cast iron. I machined them as one piece and apart from the slot all the cutting was with a 25mm end mill, where it matters they are good to within 2 thou.

So hopefully they will be ok for the job I have to do, should be as its pretty loose on tolerances, and they should be ok for everyday jobs.

Good fun making them, just need to go over them with a 800 paper wrapped file and then black them, I may mill a couple of slots along the sides and make up a couple of U shaped top clamps.

Edited By Ron Laden on 22/05/2020 14:22:11

[Thor 🇳🇴Participant @thor]

Hi Ron,

Nice V blocks, I made a pair some years ago, they have been used often. Mine have a slot along each side so they can be clamped to the milling machine table.

Thor

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Ron, look good to me, and yes a couple of slots on the sides would be a good idea you'll be glad you did when you get a job that needs them.

Regards Nick.

[old martParticipant @oldmart]

I made a much cruder vee block out of a foot of 3" channel section steel. I wanted to section a Skeeter gearbox rotor shaft for display. It was good enough to hold it while milling out an 15" by 4" bit to see the innards. The tube was much harder than anticipated and used up about 5 solid carbide end mills.

At the museum, we are fortunate to have at least a dozen, some in pairs which have been donated over the years. I have bought a couple of really big ones on ebay, most people don't want a foot long one so they go for low prices, the channel has been pensioned off after only one job.

Edited By old mart on 22/05/2020 18:16:15

[Ron LadenParticipant @ronladen17547]

Thanks guys,

Thor, looking at the link of your blocks I think I will put a clamping slot in each side of the blocks and make up some clamps for fixing down to the table. Plus if I take a mil or two off the the top faces to increase the width I can drill and tap for fixing clamps which I can also make, yours look good.

A question I do have re cast iron, is it possible to surface harden cast iron, I tried looking it up but got mixed messages, some said no, some said yes but saying you need to know the make up of the iron first and at that point I got a bit lost.

Ron

[VicParticipant @vic]

Nice job Ron.

[Clive Brown 1Participant @clivebrown1]

Posted by Ron Laden on 22/05/2020 20:11:41:

A question I do have re cast iron, is it possible to surface harden cast iron, I tried looking it up but got mixed messages, some said no, some said yes but saying you need to know the make up of the iron first and at that point I got a bit lost.

Ron

Many CI lathe beds are surface-hardened, then ground. Not a diy job I suspect. My elderly CI(?) Eclipse vee-blocks aren't hardened though.

Clive

Edited By Clive Brown 1 on 22/05/2020 20:24:30

[Ron LadenParticipant @ronladen17547]

Thanks Vic,

Clive, it did make me think that it probably is possible but as you say not a job for a small blowlamp and dunking in water.

Ron

[Pete.Participant @pete-2]

They came out really nice, they would make a nice a little project to practice hand scraping.

[Thor 🇳🇴Participant @thor]

Hi Ron,

You asked about the possibility of surface hardening Cast Iron, if you scroll down this page, you will find a description of flame hardening and induction hardening of Cast Iron. As Clive says, it is often used on machines CI surfaces like lathe bedways. Probably not easy to do in a model engineers workshop.

Thor

[Ron LadenParticipant @ronladen17547]

Thanks Thor yes I read a bit more last night, not for the home workshop or at least not mine. I, m sure the blocks will be fine as is, not knowing any different I guess I was hoping it would be as simple as hardening a piece of silver steel but clearly not.

[AdrianRParticipant @adrianr18614]

Hi Ron,

Recently in another thread there has been a discussion on how best to mill a 45 degree angle. Just wondering how you did it?

Adrian

[Mike PooleParticipant @mikepoole82104]

I would think that hardening of any method would risk distortion and need a finish grind after hardening. Unless you have an extraordinary amount of work planned I would leave as they are. If wear does become apparent I am sure a vist to the mill for a clean up pass would be easier than adventures with heat treatment. I think you have made a very useful tool that now it’s available will find lots of use.

Mike

[lfoggyParticipant @lfoggy]

Look very good to me.

Not all V blocks need to be precision ground and hardened. It all depends what you use them for. If they did the job then they are a success!

[John HaineParticipant @johnhaine32865]

The ones you buy may have been made for toolroom use where they get a lot more use than in our workshops, hence the hardening so they wear less. Then they have to be ground because of the distortion.

[lfoggyParticipant @lfoggy]

I have a pair of Starrett no 268 v blocks that are neither hardened or ground. Not precision but very useful for some jobs.

[Ron LadenParticipant @ronladen17547]

Thanks guys, I did read last night that the process causes distortion so I will leave that alone.

Adrian,

A picture below of one of the finished blocks in the vice the way I had it set up for cutting the V. I clocked the block from the spindle making sure I had the diagonal vertical and then used the end mill to cut down to just shy of the finished depth.

I then in turn set the block up in the vice with each face horizontal to give a finishing cut having first clocked the vertical face true and square. It seems to have worked as checking the V with a square and also a Stevenson block the V looks to be pretty well spot on 90 degrees or at least as my eyes see it.

Hope that makes sense.

Ron

[lfoggyParticipant @lfoggy]

Much as i love making stuff I often wonder about the economics of projects like this. Just buying the cast iron stock may be more than some cheap Chinese made V blocks off ebay.. If you had the cast iron lying around that would be different but my scrap box is not that well stocked unfortunately so I end up having to buy most raw materials….

[Ron LadenParticipant @ronladen17547]

I know what you mean foggy but it is nice when you make parts/tools for a specific job or general use and they turn out well and work.

I did have the cast iron on the shelf from last year but looking at the cost the piece would be just over £10 + £5 postage if I had to buy it now. I could buy a pair of V,s complete with clamps for £20 free postage, what they would be like I don't know, probably OK for the job I have coming up as its not tight on dimensions.

I could set the job up without a pair of V,s but the lump of iron kept staring at me.

[not done it yetParticipant @notdoneityet]

A question I do have re cast iron, is it possible to surface harden cast iron, I tried looking it up but got mixed messages, some said no, some said yes but saying you need to know the make up of the iron first and at that point I got a bit lost.

Some castings come with surfaces already hardened? 🙂 People sometimes go to considerable trouble to reverse that characteristic – or just send them back for a replacement.🙂

[SillyOldDufferModerator @sillyoldduffer]

Posted by not done it yet on 24/05/2020 06:48:46:

A question I do have re cast iron, is it possible to surface harden cast iron, …

Some castings come with surfaces already hardened? 🙂 People sometimes go to considerable trouble to reverse that characteristic – or just send them back for a replacement.🙂

The usual way is to quickly cool molten cast-iron in the mould, producing chilled cast iron. Chilling creates a hard skin, sometimes extremely hard. Obnoxious when castings that must be machined later are accidentally cooled too fast at the foundry. And it's not unusual!

This page quotes methods from Machinery's Shop Receipts and Formulas. Published in 1911 when H&S wasn't a major concern and many anti-social chemicals were sold over the counter no questions asked. Typical example:

I have successfully case-hardened cast Iron, using the following receipt: Pulverize and mix together equal weights of saltpeter, prussiate of potash and sal-ammoniac. Make a dipping solution by adding to each quart of cold water 1 ounce prussiate of potash and ½ ounce sal-ammoniac Heat the cast iron pieces till red-hot, roll them in the powder, and then plunge them into the liquid.

Sal-ammoniac is Ammonium Chloride, easily obtained and and prussiate of potash is either yellow Potassium Ferrocyanide, or red Potassium Ferricyanide. Unfortunately Saltpetre is Potassium Nitrate – an explosives precursor, and a bit tricky to buy. I guess the mix hardens cast-iron by Nitriding.

I don't think the process is particularly dangerous, but a controlled chemical is needed and the object has to be brought to red-heat. I'm not aware of a modern equivalent that can be bought off the shelf or prepared at home using ordinary stuff.

I'd put the Machinery's Recipe in the 'possible but impractical for me' category. But someone prepared to flash the cash and jump through the hoops needed to get the chemicals could have a go.

Probably easier to make V blocks out of steel…

Dave

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