Retrofit of Juuma/Quangsheng Frog Assembly to Clifton No. 5 Hand Plane

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27 Oct 2022
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Hi all.

This as promised is to report how fitment of the bronze Juuma (Quangsheng/Wood River pattern) frog assembly (found by chance in Germany thanks to a helpful gentleman) to my old and very troublesome year 2000 approx. Clifton No.5 plane went – perhaps somebody else will want to do similar.

None of this would make any commercial sense – it’s been very labour intensive.

The equivalent Quangsheng and Wood River items as seen in the UK seem to be dimensionally the same, but in cast iron and ss (stainless steel) respectively.

it seems best to start a new thread since the existing one started out by asking whether anybody knew where a Clifton frog could be obtained and became quite long. (silence was the stern reply so far as sourcing a Clifton frog was concerned) This is the original thread: Frog and adjuster knob needed for Year 2000 Clifton no.5 Plane

The following relates to this specific case – it’s unclear whether later Cliftons utilise the same dimensions. (probably?)

The very good news is that the Ju (Juuma) No. 5 bronze frog assembly and lever cap (a) more or less (see below) dropped straight in – the dowel placement as before was the same and (b) they were well made and accurately machined. (see pic of finished plane)

It’s working very nicely and freely and enables the 0 – 4mm+ mouth opening range possible in the Clifton sole.

The bronze used in the Ju items seems by the way to produce a slight but noticeable reduction is friction when adjusting the depth of cut.

There were only two practical differences in the Ju frog versus the original – the vertical back face is about 2mm further forward (see close up pic), and the thickness above the mounting bed/land is 0.8mm less than was the case on the Clifton item. 0.8 thick washers as before soldered (for convenience) under the ss Clifton dowel heads fixed the latter difference. (see pic)

The slightly shorter Ju frog could have been accommodated by placing a packing washer under the the tab which engages with the frog position adjusting screw. A new tab (not essential) was made from thicker ss to tighten the fit in the Clifton screw slot.

This brings up the matter of the further problems which emerged with the Clifton sole. Its out of flatness, out of the square side and roughly milled and not very flat frog bed were sorted when they first came to light, but it subsequently emerged (should have checked more carefully first) that the sides of the original frog were machined out of parallel by about 0.5mm - meaning that it could not hold its alignment in the sole.

This was the reason (since Clifton replacement parts seemed not to be available) for trying the Ju frog.

It emerged that the Ju frog would enter at one end but could not be slid along the bed in the sole, this because the vertical sides of the bed were curved (perhaps hand filed in the factory????) – luckily inwards. It’s hard to think other than that there was chicanery afoot to get frogs to fit without having to bother with the inconvenience of maintaining reasonable tolerances...


An hour’s very careful work with a file attached to a steel block with double sided tape left the Ju frog closely fitted but sliding between two straight and parallel vertical sides to the bed.

Three residual OEM Clifton machining issues in the sole could not be sorted - the vertical sides of the bed were well under 1mm high (just about functional. but not enough meat in the casting = minimal side to side bearing area for the frog), the frog bed was machined off centre in the sole by about 1mm side to side (meaning that the iron if centred hangs about 1mm off the side of the frog) and the frog adjusting screw threaded hole was several degrees (visually obviously) out of vertical alignment with the plane of the frog bed. The frog locking screws work fine but are not accurately aligned with the dowels.

The misalignment of the adjusting screw caused the new frog tab to bind in its adjusting screw, but filing a tilt into the conveniently raised pad on the back face of the Ju frog got it working. (see close up pic again)

We have a light milling machine so it seemed preferable to deepen the recess in the back of the frog bed (the original was semi-circular – see pic of sole) to increase the travel of the adjusting screw accommodate the slightly shorter Ju frog. The as cast (and prone to causing loosening) out of flat rear handle/tote mounting surface was skimmed flat at this time too. The pic of the finished sole shows both.

Holes for Veritas style iron locating grub screws were drilled and tapped M6 in both sides of the sole. (see first pic) Experience with Veritas planes has shown that these are very useful.

They mean that the iron always rotates about a fixed point half way between them when the lateral adjuster is used (gives very predictable side to side/tilt adjustment), the iron drops repeatably back into the same location after sharpening, they can be used for fine side to side adjustment of the iron and they mean that the lever cap doesn’t have to be locked down too tightly to stop the iron wandering about under cutting forces which (see below) results in much easier adjustment of the depth of cut.

A lot of care is needed in placing the grub screws so that they at least partially overlap the sides of the iron over the full range of mouth opening and are above its bevel. The ends need to be carefully squared/flattened. (finished length 6mm approx.) A small drop of low strength thread locker (222) on a lightly oiled screw means that they stay put but remain adjustable.

The Ju frog (because of the inaccurate OEM centring of the frog bed in the Clifton sole) required notches milled on both sides (see pic) so that it didn’t catch the grub screws when fully forward/set to a tight mouth opening.

The Ju bronze lever cap was (with the Juuma logo milled off and then polished) was used because the ss Quangsheng item bought last year was over polished. This so that the surface that the centre screw bears on was sloped – causing it to tend to squeeze out when locking it down. The Ju item did not have this problem and the bronze turned out to make depth of cut adjustments slightly easier.

The pressed steel lateral adjustment lever in the Ju frog turned out to be a good fit in the iron and is well made. It was left untouched.

A Wood River style steel Y lever (see pic) bought last year from Fine Tools in Berlin was fitted to the Ju frog because the lobed tip was a very slightly tighter fit than the bronze Ju Y lever in the Ju cap iron slot- the bronze item was actually fine. It needed a light relieving with a file below the lobe on the top side (as pic) so that it didn’t bind at full mouth opening/with the iron fully forward.

The Clifton cryogenic iron obtained last year turned out as before to be warped lengthwise and very coarsely ground – so the original (and good) forged Clifton iron was retained. The cryogenic iron could perhaps have been used, but rough surface finishes make for a stiff depth of cut adjustment.

The Ju cap iron (also available as a spare from Fine Tools in Berlin) was tuned and fitted. Both it and a Quangsheng item seen recently were a little crudely formed and slightly out of square (but likely functional) at the business end. Twenty minutes of fine tuning and polishing guaranteed a close fit on the top of the iron.

The Veritas style side to side iron locating screws open the way to the following - reduced lever cap pressure and a fairly quick polish of the sliding surfaces (top of the cap iron and bottom of the iron) on progressively finer waterstones (just a light touch that hits the high points - to 12,000 grit in this case) followed by waxing greatly reduces the friction/stiffness of the depth of cut adjustment.

Reducing this friction too much without the locating screws could lead to the iron wandering side to side under cutting loads.

The result is a very nicely functioning bitsa with everything in good alignment and with a low friction depth of cut adjustment. Thanks to the Juuma parts there’s a few degrees over 1 turn of backlash in the adjuster which by the standards of these things is very good.

The mouth adjustment goes freely from zero (metal to metal/frog fully forward) to the 4mm+ permitted by the Clifton mouth should the latter be required for coarse work.

The frog as a consequence of the accurately flattened frog bed and flat frog base unlocks and moves freely within a few degrees turn of loosening of the lock down screws. This is markedly unlike the original as first received.

A long and gradual tightening of these screws suggests that the frog base and bed are not flat and that tightening is twisting something.

Hope this helps…


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How does the plane work (how well) when it's tightened? If everything is solid, even if being distorted a bit, it might be within the tolerances of the plane design with the lever cap down.

That frog looks identical to LN - if anyone is looking at this, woodriver planes in the US stopped using that shortly after WC's relationship with Lie Nielsen ended. That doesn't mean the WC frog won't work on a clifton or LN plane, but it may be slightly different in dimension since WC moved toward making the frog look more like stanley's and less like Lie Nielsens (for obvious reasons).

it's fairly obvious those frogs were either scanned and designed or just made from castings using an original LN.

This is quite an undertaking - hopefully you'll like using the plane for a long time!
The fact that Clifton went from making a forged iron from a steel that is less dimensionally stable and warps more in heat treatment to a warped iron in a steel that's very well known for its stability in heat treatment is really surprising!
Ta for the interest DW.

Definitely not a commercial undertaking. Not even practical unless you are retired/have a lot of spare time.

I've only given it a quick trial in a light cut on some iroko, but all seems fine.

The warp in the Clifton iron probably (?) would not have been much of a problem in use (it could well have clamped down - even though it's rather thick) but I set it aside without sharpening since I had the original forged iron.

The misalignments in the frog bed in the sole have been removed, it locks down hard in a fraction of a turn of the hold down screws. The mouth alignments have ended up spot on. I was referring to how it was when bought in mentioning that a slow tightening of the frog hold down screws may indicate a misalignment.

These bedrock planes are a bit of a minefield in dimensional and alignment terms - there are so many interdependent parameters. Luckily the Juuma frog assembly was spot on and the inaccuracies in the Clifton sole were such that they could be fixed by removing metal.

The lever cap is definitely Juuma, but my polishing it probably makes it look more like a Lie Nielsen item. The Quangsheng stainless version is identical. I guess that ultimately they all do versions of the original Stanley.... : )

I've attached some blurry pics (phone camera not focusing properly) of the Clifton cryogenic iron for interest showing the warp. The forged Clifton irons seem to have a good reputation (the example in this plane is good anyway - it's nice and flat, and it sharpens well and holds its edge) - could the switch to a cryogenic item have been economically motivated?


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Ahh...thanks for the clarification. The amount of warping shouldn't be a problem if the cap iron and lever cap bend it out and it doesn't have some odd undesirable bias (like a short steep high spot or significant twist).

I have made a lot of irons, but never surface grind them afterwards (make them by hand). Most small issues dimensionally are constrained by the plane.

You're right on discussing adjustment feel based on surface (frog, iron, cap iron, lever cap shape/surface ....all of it can make a big difference in feel).

Not sure if you can tell, but it's also possible and maybe likely that an iron that's not hardened from end to end will be a lot less slick adjusting than one that is fully hardened from end to end.

To get a flat iron out of the latter, it would be hard to get full hardness end to end without having a plate and forced air procedure to quench. A2 would be OK with that, O1 wouldn't.

The clifton hardened area (A2) looks well short of the slot unless that's just where the machining is different. It can be troublesome on something oil quenched if the slot gets into the oil too far too fast, so I wouldn't be surprised if that last fraction of in inch is unhardened.
You're way ahead of me on the practical metallurgy, but for sure softer steels have a gumminess about them.

The original forged Clifton iron has that hard/tough/slick feel of say a tool steel for it's full length, the cryogenic one somewhat less so. (could be mistaken)

I flattened the back of the cryogenic iron behind the edge before I discovered the warp and it's definitely tough stuff until almost the slot. (it could be that polished area which you are seeing, although there is a differently textured zone which extends back beyond that too which could be to do with heat treatment)

It seems a bit softer from there back judging by a quick scratch with a hardened scribing tool - but the surface finish gets rougher there too which could be misleading......
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