Supplier of 7/32″ Dowel Pins Please?

[B TulleyParticipant @btulley]

I'm looking for a supplier for two 7/32" dowel pins please (not tapered), 16mm or longer. I want to make my own Knurling tool and the pins will be used as axles for the wheels.

I can easily get them from Boneham at 12p each (the price is right &nbsp but then there's £7.50 +vat on top for postage, which makes a couple of dowel pins rather expensive

I've tried ebay etc. but 7/32" are a bit thin on the ground. Any suggestions please?

Many thanks,

Brian

[B TulleyParticipant @btulley]

[DiogenesIIParticipant @diogenesii]

..wouldn't it be cheaper to buy another set of 'wheels (with a more conveniently-sized hole) and base the build around those?

[bernard towersParticipant @bernardtowers37738]

You could try hardening a couple of pieces of EN8

[pgk pgkParticipant @pgkpgk17461]

silver steel?

I didn't bother hardening the axles on my DIY job .. it doesn't get a huge amount of usage and I figured I’d just swap them out if a problem occurred.

pgk

[B TulleyParticipant @btulley]

Posted by DiogenesII on 22/04/2022 18:02:53:

..wouldn't it be cheaper to buy another set of 'wheels (with a more conveniently-sized hole) and base the build around those?

That's an option, but ideally I want 5/8" diameter and not too wide – Chronos have 5/16" wide at a good price with 7/32" holes. RDG's are 3/4" dia. with 1/4" holes – which is easier as regards the dowel pins. A friend managed to find 5/8" and only 3/16" wide, with 1/4" holes, though I'm not sure where from. 1/4" wide would be nice, though I've not seen any yet; price is also a consideration – it's an interesting project but if it gets too expensive it starts to make more sense just to buy a ready-made unit.

As the tool will be used on a Taig (and so on small components) I'm very conscious of not overloading or asking too much of the machine; the tool will be a twin wheel clamp-type device.

Brian

[Ramon WilsonParticipant @ramonwilson3]

Brian – you may find that a dowel pin might be tight in the knurl – dowels being slightly oversize for a given diameter.

My clamp type knurling tool made many years ago still has the original (unhardened) silver steel pins as previously suggested by 'pgk' from when I made it. Whilst I wouldn't say it's done a vast amount of knurling it's certainly done it's fair share over those years without issues and is more than suitable for the task in hand on a small lathe and home usage

Though not answering your question specifically just a thought to consider perhaps

Tug

[DC31kParticipant @dc31k]

In the same vein as the silver steel suggestion, how about an HSS drill blank of the correct diameter (£3.19)?

[David George 1Participant @davidgeorge1]

Hi Brian I made a knurlingtool from push type to make my clamp type and have changeable rolls for different size cuts using the original pins . I have another which you can have for free as it is not suitable for my lathe. Just drop me a message if you want it.

My knurling tool.

spare tool.

David

[B TulleyParticipant @btulley]

Posted by pgk pgk on 22/04/2022 18:11:29:

silver steel?

I didn't bother hardening the axles on my DIY job .. it doesn't get a huge amount of usage and I figured I’d just swap them out if a problem occurred.

pgk

Many thanks – Silver Steel had crossed my mind as a Plan 2…

[BazParticipant @baz89810]

Buy a length of 7/32 silver steel, you will be able to make a couple of spare sets out of a length. Don’t bother hardening them, if you wear them out put new ones in.

[B TulleyParticipant @btulley]

Posted by DC31k on 22/04/2022 18:54:08:

In the same vein as the silver steel suggestion, how about an HSS drill blank of the correct diameter (£3.19)?

Now that is a good idea – I had pondered HSS Drill Shanks but buying two drills and then scrapping them for the shanks seemed an awful waste (and a lot more expensive than drill blank). Many thanks

[B TulleyParticipant @btulley]

Posted by David George 1 on 22/04/2022 19:51:59:

Hi Brian I made a knurlingtool from push type to make my clamp type and have changeable rolls for different size cuts using the original pins . I have another which you can have for free as it is not suitable for my lathe. Just drop me a message if you want it.

My knurling tool.

spare tool.

David

That's very kind of you David – many thanks. Unfortunately I need to make a simpler version of your own very nice knurling tool as I'll be using it on a Taig/Peatol Lathe and am very conscious of not overloading the (very small) Headstock.

[Howard LewisParticipant @howardlewis46836]

Silver steel was the first thought that came to my mind.

As for chopping the end off the shank of a couple of 7/32" drills, the shanks won't be so short that they could not be used, would they|?

Although, silver steel would still be my first choice.

Used "As is" should give a reasonable life, but if you are worried, the pins could be hardened before assembly.

Howard

[DiogenesIIParticipant @diogenesii]

Rotagrip might be worth a call – I know he carries knurls, I've seen 5/8 x 3/16 listed in his Ebay store which I think are 'when he has them, he has them', I think 5/8 x1/4 is a standard industry 'stock' size, as is (I think) 1/2 x 3/16 is; mine are this size.

I've always had found it easier to obtain a passable result with 3/16 wide wheels in my small lathe.

As others have said, I've used (and still have fitted) silver steel pins – nominal dia., cut to length and hardened as is.

Edited By DiogenesII on 22/04/2022 20:42:31

[DC31kParticipant @dc31k]

Posted by Howard Lewis on 22/04/2022 20:32:11:

As for chopping the end off the shank of a couple of 7/32" drills, the shanks won't be so short that they could not be used, would they?

No, but they will neither be hardened nor will they be 7/32" diameter.

[Mike PooleParticipant @mikepoole82104]

The Marlco knurler used 7/32 pins and I used hardened silver steel to replace the ones on mine, it has worked fine so far but I am not an industrial user. The shank of a drill is likely to be undersize as there is a very slight reduction in diameter from the tip of a drill. The pins are a friction fit in the body of the Marlco and this is probably the critical part of the pin size, the knurl is only going to run on one side of the pin so a good fit is probably not too important.

Mike

[B TulleyParticipant @btulley]

Posted by DiogenesII on 22/04/2022 20:42:02:

Rotagrip might be worth a call – I know he carries knurls, I've seen 5/8 x 3/16 listed in his Ebay store which I think are 'when he has them, he has them', I think 5/8 x1/4 is a standard industry 'stock' size, as is (I think) 1/2 x 3/16 is; mine are this size.

I've always had found it easier to obtain a passable result with 3/16 wide wheels in my small lathe.

As others have said, I've used (and still have fitted) silver steel pins – nominal dia., cut to length and hardened as is.

Edited By DiogenesII on 22/04/2022 20:42:31

Many thanks for the Rotagrip suggestion – they have numerous sizes including 5/8" dia x 1/4" thick & 1/4" bore, which would be fine I think.

One question – what number of teeth do others generally use – Rotagrip have a fair selection: 68, 74, 88, 92 and 120 Teeth. Of course I have no idea what diameter I'll be knurling, but as it's on a Taig it'll most likely be smaller diameters.

[Anonymous]

Posted by B Tulley on 22/04/2022 20:24:06

…two drills and then scrapping them for the shanks seemed an awful waste…

You don't buy drills just for the shank. Drill blanks are available:

Drill Blanks

With quality drills the shank is usually a thou or so smaller than nominal diameter, so drill blanks are better.

Andrew

[B TulleyParticipant @btulley]

Posted by DC31k on 22/04/2022 20:49:57:

Posted by Howard Lewis on 22/04/2022 20:32:11:

As for chopping the end off the shank of a couple of 7/32" drills, the shanks won't be so short that they could not be used, would they?

No, but they will neither be hardened nor will they be 7/32" diameter.

presumably those issues wouldn't apply to drill blanks – or would they? I do like the s/steel option though.

[Martin KyteParticipant @martinkyte99762]

If you use silver steel and harden ,just be aware that the diameter will get bigger. Some reduction will be found on tempering but don't just assume that the pins will remain the same size.

regards Martin

[Ian PParticipant @ianp]

Posted by Martin Kyte on 22/04/2022 22:14:38:

If you use silver steel and harden ,just be aware that the diameter will get bigger. Some reduction will be found on tempering but don't just assume that the pins will remain the same size.

regards Martin

How does hardening silver steel increase its diameter?

Ian P

[Anonymous]

Posted by Ian P on 22/04/2022 23:06:47

How does hardening silver steel increase its diameter?

The internal atomic structure is changed, which in turn changes the dimensions. It may only be tenths but it is measurable.

Andrew

[HopperParticipant @hopper]

You will likely find the hole in the middle of knurl wheels is a nominal size only. In practice it could be a bit over or a bit under size. I made my pins out of 6mm silver steel but had to machine it down slightly to fit the hole. It needs to have working clearance to let oil into the load bearing surfaces. Some commercial units are made a very sloppy fit there and work well. Pins were made threaded on one end for retention and screw driver slot on the other end.

I hardened and tempered my silver steel pins with no problems re getting bigger. Growth of a few tenths of a thou is ok if you leave a thou or three clearance.

Edited By Hopper on 23/04/2022 00:27:24

[not done it yetParticipant @notdoneityet]

Never mind the minute expansion/contraction changes, when hardening. The material will be altered in a slight warping way. Items hardened will change dimensionally due to internal stresses caused.

Much like bright mild steel (where the material can seriously warp if machined on one side, due to surface stresses in the material when cold rolled.

Precision items need a ground surface finish after hardening and tempering, for that reason.

[Author]

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