Burnerd Multisize EC Collet Chuck - replacement KEY

I am wondering if anyone knows if the Jacobs K5 chuck key fits the Burnerd Multisize EC collet chuck. The number of teeth of the K5 is 12 and the pilot size is 7/16" which both match so I am thinking on the off chance it might work, especially as the Jacobs chuck 20N (for the K5 key) has a toothed sleeve diameter of 3.65"  whereas the Burnerd Multisize chuck has a toothed rack diameter of  about 4 1/4". I cannot find any other specs on the K5 but the Burnerd key has an outer maximum diameter of about 1 5/32". Pursuing Burnerd for a replacement key is not producing much joy. The K5 costs about £20 so I thought I would check here first before buying to try.

Edited By Adam Harris on 09/11/2020 18:42:16

Edited By Adam Harris on 09/11/2020 18:56:05

Some Burnerd dimensions possibly that might help:

Pilot 0.435"

Teeth 12

Big end 1.155"

Small end 0.880"

Tapered portion 0.485"

Just had a look at Pratt-Burnard data base table. And part No 4010-11380 for the key.

It says the chuck should be KC15 with EC collet.

I don't know if it helps but I would try Rotagrip for a replacement.

David

Thanks David. I have just looked them up and I see £102 for the part!! I am hoping a Jacobs K5 will work and if not, will attempt to make one.

Edited By Adam Harris on 09/11/2020 22:35:18

Checking my ebay purchase history i bought a K4 from rotagrip for exactly the same job. I seem to recall i had to sleeve the spigot, but teeth are correct.

Hi Mark - is that a typo? The K5 looks the closest (you said K4)...

My purchase history links to this

**LINK**

From memory I already had one of these so knew the teeth meshed correctly before I bough this one. I bought a second one as I intended to graft it into a long T handled shaft like the original. Happy tobpost photos of the mesh later today.

Edited By Mark Davison 1 on 10/11/2020 05:21:22

I think the larger K5 , already on a long T handled shaft, will work better, but i will update the forum on its suitability when I receive it

Mine is definately a K4. Does the K5 have the same tooth profile? I did have to put a brass sleeve around the spigot.

I will let you know next week when it arrives

The K5 arrived and it is too big but it does work pretty well. Its max diameter is 32mm as opposed to the Burnerd key which is only 29mm max diameter. It touches the circular recess which actually gives it some support resulting in less slop than the Burnerd key. Tooth fit seems good. The length of the teeth engagement is only 6.7mm as opposed to the Burnerd which has engagement length of 11mm so that is less sound but actually the engagement depth of tooth is the same, and if you are not careful with the Burnerd key slop (ie you allow the Burnerd key to turn in a non-perpendicular fashion which is easily done), then the K5 tooth depth engagement is superior. I will try to find a K4 for further comparison.

Edited By Adam Harris on 14/11/2020 13:41:07

Just found a Jacobs K4 in a drawer. It is smaller than the Burnerd with a max diameter of 28mm (Burnerd 29mm) and a smallest diameter of 22.5mm (Burnerd 23.2mm) and the tooth length is much shorter with a maximum length of 12mm vs Burnerd of 16.5mm. This does reflect a noticeably steeper angle of taper of tooth length than the Burnerd. The K5 on the other hand has the same angle of tooth length taper as the Burnerd. It is difficult to estimate tooth depth of engagement of the K4 without a sleeve to centralise the spigot, but in attempting to hold the K4 as if it had a sleeve, it appears to me that the depth of tooth engagement is not very good and certainly not as good as with the K5. The K4 tooth depth of engagement reduces as it goes towards the centre of the chuck, but the length of engagement is about 12mm (the K5 length of engagement is only about 6.7mm). So with the K4 you have long but progressively shallower tooth engagement, the K5 short but deeper and consistent tooth engagement. Horses for courses?

Edited By Adam Harris on 14/11/2020 15:22:04

Edited By Adam Harris on 14/11/2020 15:22:25

Edited By Adam Harris on 14/11/2020 15:26:00