Filing rest – hardened guides ruining files

[Mike DonnerstagParticipant @mikedonnerstag]

I recently made a Hemingway filing rest, hardening the rotating silver steel guides as stated in the instructions. These rotate freely though, being hardened, files don’t have any ‘bite’ on the guides and skate over them without them rotating. Furthermore, I found that the teeth on the files were bluntened very quickly.

Has anyone had a similar experience with hardened filing guides?

Thanks in advance,
Mike

[Mike DonnerstagParticipant @mikedonnerstag]

[Anonymous]

Armchair – check

Popcorn – check

Beer – check

Let battle between hardened rollers and soft rollers begin!

I don't have a filing rest, but when using filing buttons I regard them as consumables and leave them soft.

Andrew

[Tony Pratt 1Participant @tonypratt1]

Just leave the rollers soft & report back.

Tony

[MikelkieParticipant @mikelkie]

Try teflon for filing rollers

[bernard towersParticipant @bernardtowers37738]

I have been using two filing rests for goodness knows how long both with hardened rollers and have never had trouble with blunting files, possibly you might be dwelling on the point where the file has done its work and you need to move onto the next flat etc.

[HopperParticipant @hopper]

All the old ME books by Thomas, Sparey, Bradley, Westbury etc specify hardened rollers. So it is long established practice.

Maybe modern cheap files are not up to the job?

Solution would be buy good files or use soft rollers. Either mild steel or delrin etc which might be better.

[JasonBModerator @jasonb]

I don't use a rest but do leave filing buttons soft.

Question for the Hardened side of the fence, what colour do you temper them to as I don't see this being mentioned just "hardened"

[HopperParticipant @hopper]

Posted by JasonB on 12/07/2022 07:17:43:

I don't use a rest but do leave filing buttons soft.

Question for the Hardened side of the fence, what colour do you temper them to as I don't see this being mentioned just "hardened"

I have mostly used soft filing buttons but recently made a pair from silver steel, hardened at cherry red and not tempered at all, out of sheer laziness. Files seemed just fine afterwards. But they are 40 year old files from apprentice days so were of good quality. And used with a suitably light touch when down to the button.

Edited By Hopper on 12/07/2022 07:23:37

[Ramon WilsonParticipant @ramonwilson3]

Posted by JasonB on 12/07/2022 07:17:43:

I don't use a rest but do leave filing buttons soft.

Question for the Hardened side of the fence, what colour do you temper them to as I don't see this being mentioned just "hardened"

Hardened buttons should be fixed – soft should be free to roll, if they don't, and without a degree of caution the file can do its work on the button too and the part can easily be spoilt.

If hardened rollers/buttons roll then the file will wear quickly as opposed to skating across the surface when fixed. Very easy to tell when the two faces contact. I have made them soft but ensuring they roll freely is often more time consuming than hardening

Like Bernard been using hardened buttons for far longer than I care to think but never bother to temper them – a quick quench and use straight away – their purpose is usually a one off and simply not worth doing. Never throw them away of course – they might get a second or more go in the future.

I made a small filing rest with hardened (rolling) rollers many years ago – spoilt a couple of files before loctiting them in place. Don't use it often I agree but it works well when I do.

Tug

[martin perman 1Participant @martinperman1]

Gentlemen,

Never come across filing buttons before could somebody please tell me what they are and how to use them.

Martin P

[BazParticipant @baz89810]

My filing buttons have always been hardened, never tempered and always allowed to rotate. New files are kept for brass and when they loose their edge they are used on steel, when they are nearly worn out they are used for filing button duty. Never had a problem with buttons rotating.

[HopperParticipant @hopper]

Posted by martin perman on 12/07/2022 08:08:13:

Gentlemen,

Never come across filing buttons before could somebody please tell me what they are and how to use them.

Martin P

If you want to file a radius on something, such as a half-round end on a piece of flat bar, or the round small end on a model engine connecting rod, you turn up two pieces of silver steel of the correct diameter with a hole in the middle and harden them. Then put them either side of the work with a screw going through the filing buttons and the work and tighten up. You then take a file and file the job down undil the file just hits the hardened disc. Result, a perfect rounded end or radius.

[Martin KyteParticipant @martinkyte99762]

I would advocate sharp files and gentle pressure to maintain the life of the file when using a filing rest with hardened rollers. However my prefference would be leave the rollers soft.

regards Martin

[JAParticipant @ja]

There is no correct answer to this.

I made a filing rest over 20 years ago and kept the rollers soft. It is not frequently used and soft rollers have not been a problem. I made my first few sets of filing buttons soft and they had to be chucked after their first use. I now hardened filing buttons and have a large selection readily at hand. There is something very satisfying about spending 15 minutes sorting through the collection instead of making new buttons.

Really it is a matter of your time. It is quick and easy to using soft tooling once or twice. After that you should think about hard tooling. We frequently got this wrong at work where cost was also a consideration.

JA

I use my filing buttons clamped, not free to rotate. As for tempering, I use the kitchen oven (modern, electric, fan heating and good temperature control).

 

 

Edited By JA on 12/07/2022 09:07:57

[Martin KyteParticipant @martinkyte99762]

Sorry for the multipost, the internet just fell over for a couple of minutes.

regards Martin

[larry phelan 1Participant @larryphelan1]

Shame on you, Martin P !!!

Even I have heard of them, just too lazy to make them !

[martin perman 1Participant @martinperman1]

Hopper, thank you for your description of filing buttons.

Larry, I'm sad to say that I've never heard or seen them even during my engineering apprenticeship they never popped up, I dont do model engineering, my grandfather did, but I restore old engines and have my own workshop and have always filed radiuses using radius gauges and following scribed lines.

Martin P

[Nigel Graham 2Participant @nigelgraham2]

I think this thread is diverging into confusingly talking about quite different tools – for quite different purposes too!

'

The OP is describing a Filing Rest, a lathe attachment used for filing flats on a turned end of the work-piece.

It guides the file by it running without sliding, on two freely-rotating rollers on a yoke of adjustable height, straddling the work from below. It allows creating polygons, in conjunction with a suitable dividing arrangement on the lathe spindle.

Hardened rollers should not hurt a good-quality file, provided they do revolve freely and the file is not made to move diagonally. I think some people have used small, sealed ball-bearings races for the rollers.

Looking at Hemingway's catalogue, their Precision Filing-Rest rollers are flanged to guide the file's safe edge. This both keeps the file on track, at right-angles to the lathe axis, and gives repeated facet lengths.

'

A Filing-Button as others describe is a template for filing arcs of its own radius.

A Button can be made to revolve (should be, if hardened) or be held rigidly to the work, usually by a screw (and nut) through the hole concentric with the intended arc, to aid forming the end of, for example, a motion-gear link.

It is meant to guide the filing, not the file, and if hardened it can soon lead to blunt files unless used with great care!

.

I don't have a filing-rest but often use filing-buttons, and sometimes the work dimensions allow this to be no more than two ordinary washers, one each side of the work. If I hit them with the file, they don't harm the tool.

[HopperParticipant @hopper]

Posted by martin perman on 12/07/2022 09:46:40:

Hopper, thank you for your description of filing buttons.

Larry, I'm sad to say that I've never heard or seen them even during my engineering apprenticeship they never popped up, I dont do model engineering, my grandfather did, but I restore old engines and have my own workshop and have always filed radiuses using radius gauges and following scribed lines.

Martin P

Hardened filing buttons set up ready to use. No files were noticeably harmed in the making of this part. File was stroked from the right to left of this photo, rocked so it followed the shape of the desired curve and so the file contacted the curved surface of the hard button when down to size, not dragged acrross that sharp edge at the front in this view.

[bernard towersParticipant @bernardtowers37738]

Jason, In answer to your question all of the drawings / descriptions I have seen go for case hardening which is how both my filing rests were made

[A SmithParticipant @asmith78105]

"what colour do you temper them to as I don't see this being mentioned just "hardened"

Not sure why you would need to temper something that won't see a shock load?

[JasonBModerator @jasonb]

As tempering also reduces the hardness as well as the brittleness of the metal I was just curious if any of the advocates of hardening then tempered and possibly did it so that the rollers were just a fraction softer than the average file. This would mean they wear well but don't damage files, also could be less likely to skid as the OP is getting.

[A SmithParticipant @asmith78105]

Tempered to achieve a hardness slightly less than that of a file? Seems possible but would require better temperature control than I can manage with a gas ring.

[Mike DonnerstagParticipant @mikedonnerstag]

Many thanks to everyone who responded to my post. I am indeed a filing rest for use with a headstock indexer on the lathe and not filing buttons for rounding parts held in a vice. The files I've been using are Swiss Vallorbe/Grobe files, hence why I can't afford to ruin any more! I'll try making the guides from silver steel, unhardened. The guides are designed to rotate, and they do rotate easily by hand. However, the files skid over them, and I assume this is contributing to the wear.

I assume this (unhardened silver steel) should cure the problem, though if not I'll try another material such as PTFE or Delrin.

Many thanks,

Mike

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