Hayter 21 axle

[Rayp 46]

Does anyone have or know where to get a key for holding the clutch back plate on the axle?  It appears to be a half moon shape and is part number 4295.  The key was missing from my 21 and from the part Osprey which I keep for spares.  Any help would be much appreciated. 

[Anglo Traction 1,016]

I may have one, Can't remember the size now, but either a Nbr  3 or 5 woodruff. Should be 1/8" wide for a 3/4" dia shaft. Measure the keyway width in the shaft and the length for me and I'll check my stock.  

[Rayp 46]

Hi Richard,

You always seem to be helping me out and I hope I can reciprocate one day!

I have endeavoured to measure the keyway and the measurements would seem to be:

length 600 thou and width155 thou although the slot in the Backplate seems to be more like 165 thou

Regards

Ray

[Anglo Traction 1,016]

No problem Ray, I try to help anyone. So it's a bit beefier than I predicted. I have to assume due to the machine's age, it is Imperial and not Metric?.

Your measurements give 2 possibilities of Key size. I reckon it could be either one of nbr 6 or 8 in this handy size chart-

 

Best thing to do is check the depth of the keyway recess in the shaft and add the depth of the slot in the Backplate to get an idea of the Woodruff Key height.They are fairly cheap, so it may be worth ordering a couple of sizes close to your findings from here - Imp Woodruff Key  to be sure of the right one (#6 would be my hunch).

The backplate slot width difference may well be due to wear.

Hope this helps, as I don't have any of those sizes. 

 

 

[Wristpin 400]

Are you sure about that part number? If I’m looking at the correct part  the book that I’m looking st says 1662.  In stock at my Hayter agent , key 505, for 94p + vat

[Rayp 46]

Thanks Wristpin.  I was sure until I saw your reply.  Following your post I have looked again at the Spare Parts Book again and can see that the nearest key (4295) to the Backplate is intended for the small sprocket and that key 1662 is the one for the backplate.  I'll have to look more closely next time!

Thank you Richard for looking through your stock and for the helpful Chart.  I ordered a couple of keys from the Link you gave me and immediately after received Wristpin's reply highlighting the fact that I had incorrectly read the Spare Parts Book.  At least if you ever need a key I may be able to help you from the two I have ordered.

[Anglo Traction 1,016]

I confess I did not check Ray's part number against the parts list, I just noted the lack of description to identify it.

Yes, Wristpin's number 505 (BS46 system) directly crosses to my 'hunch' number 6 on the (US) Chart I posted.

 

Here is a handy size chart that covers DN6888 metric and BS46 imperial comparisons. It is a link to a UK company, as I was unsure if I am allowed to put a company's document in the the Files section here. You can download your own copy though.

Woodruff Key Chart 

 

 

 

[Rayp 46]

Thanks Richard - this will make another useful addition to my 'library'

[Rayp 46]

I have finally reassembled the 21 and Wristpin was right!  It no longer slips the clutch, but has only one speed fast!!!  After 'running; and hanging on for 3 1/2 hours mowing I will have to try and buy a wheeled seat.

The only problem I have with it now is vibration which loosens the nuts on the cover and height adjuster.

[Anglo Traction 1,016]

Good to hear it's a 'runner'. Keeps you fit Ray at that speed. Presume you know the imbalance/vibration is likely to be with the disc or blades....be the first place I would look. 

[Wristpin 400]

That's all good news. Interestingly I don't remember the single speed 21s being that fast  - but I was younger and fitter then!!  

 

EDIT. Just looked back over your earlier posts and don't see any images of the transmission gearbox input pulley - is it single or double?  It's just possible that you have one of the not very common two speed machines with   double crank and gearbox pulleys and a thin, toothed (and expensive) belt.  In 30+ years in the trade I only saw a couple of them. One was owned by an old boy with two "tin legs" who used it with a seat to drive the half mile through the woods to the pub having had his licence withdrawn.

[Rayp 46]

Thanks Richard and Wristpin.  I will check the disc and blades as suggested and the transmission gearbox input pulley to see if I do have a two speed machine and will report back in due course.