mortise bits too long for chisel?

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selly

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Hi,

I have a multico m1 bought second hand which I have struggled in my amateur way to understand. Since having figured that i need collets I have also bought some new bits from here:

http://cgi.ebay.co.uk/Multico-Morticer- ... _500wt_922

Firstly can i presume a 6mm bit will fit into a 1/4 chisel and a 12mm into a 1/2 chisel? The other problem I have is that the bits appear too long for the chisel. What do i do about this - cut off the bit too length and then flatten an edge on the shaft to allow the grub screw to fit? I don't really want to buy new chisels are these are sharp and original multico.

Its so frustrating being self educated on some of these things. :(
 
I would have assumed that a 6mm bit would be the auger to fit in a 6mm chisel and so on but I can't imagine the size difference having too much impact on cutting.
Too long is far less of a problem than too short!

I would just cut them down especially as you have quality chisels.

Don't forget to allow a working clearance for the auger.
When you fit the chisel, insert a 2p coin between the chisel collar and the morticer. Fit the auger as far up as it will go (once shortened) then loosen the chisel, remove the coin and raise the chisel as far as it will go.

Bob
 
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Mortiser bits and chisels are usually matched pairs, but looking at mine, the auger is not a precise fit - so long as it all rotates without fouling it seems OK. The biggest problem would be if the auger part is too long for the chisel and fouls the inside top.

I've bought spare sets on occasion and the auger is often too long and protrudes below the chisel when fitted in the macine (An Axminster). In these cases I measure the excess protruding below and cut that much off the other end; generally it's about 35mm or thereabouts.


Some other tips that work for me:

To overcome the friction within the chisel bit and at the cutting head (even with a gap as mentioned by Bob) I use extra-gloopy Oregon chain saw oil, sparingly, of course: I cut Oak a lot and it's hard work for the chisel.

As well as keeping the inside edge of the chisel keen, put a shine on the outside edges on your finest stones to reduce friction.

Run a candle up and down the outside of the chisel to prevent binding in the slot, especially the first plunge.


.
 
Whilst we are on the topic, has anyone found a sharpening set for chisels bigger than 12mm- 1/2"

If not how do you keep your bigger chisels sharp? Take them to the saw doctor perhaps?

Bob
 
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Good point, Bob.

They must exist. Personally I seldom go bigger than 1/2", which I use the most, but as I said, I find it easier to stone the outsides.

Clifton market one up to 1/2" but it's a bit of a toy in my opinion - at least mine broke easily.

Having said that, I tend to use the cheapo-cheapo far- estern ones so it doen't break my heart if they pass to the other side.
 
Argus":3nr65qo6 said:
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Good point, Bob.

They must exist. Personally I seldom go bigger than 1/2", which I use the most, but as I said, I find it easier to stone the outsides.

Clifton market one up to 1/2" but it's a bit of a toy in my opinion - at least mine broke easily.

Having said that, I tend to use the cheapo-cheapo far- estern ones so it doen't break my heart if they pass to the other side.

I wonder if they really do exist. I've even looked on the other side of the pond without success. Stoning the outside is all very well for a couple of light touches but after that there will be a significant taper and risk of jamming esp on deep morticing.

Bob
 
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Yes, Bob, I guess there is a risk of tapering, but by stoning the outside I should say a complete wipe of the whole side's effective cutting surface flat on a fine diamond stone with some water and a polish with rouge at the tip.

having said that.... I don't find the best quality chisel sets cost-effective compared to the cheapo-cheapo ones.

Otherwise I guess that you coud make your own?

I cut slips to shape for my carving tools with a hacksw and old files from old Japanese waterstones. It should be possible to 'turn' a bit to the right inside shape? Maybe?????

Never done it but possible, no doubt.

.
 
9fingers":1nuqow8b said:
Whilst we are on the topic, has anyone found a sharpening set for chisels bigger than 12mm- 1/2"
Mine has a tapered square shank to fit an old-style brace, and has an overall diameter of about 1.25" (not that my Multico will cope with more than 1/2"). It's stamped "Monninger HSS No2 539" and came out of a box of odds and bobs at a car boot sale for a few pennies ( 8) ). But, I'm pretty sure Record used to make an almost identical product.
 
I have just had a bit more of a search for sharpening sets

Axi now seem to carry them but the down side is £115 for 3/8-3/4" and £171 for 3/4-1" :shock: :shock:

I will have to continue searching for a mortgage now or visit some car boot sales.

I can make the guide mandrels OK but just need the HSS bit. even if that was blunt I could re-grind it.

Bob
 
9fingers":1aiqoeuw said:
Axi now seem to carry them but the down side is £115 for 3/8-3/4" and £171 for 3/4-1" :shock: :shock:
I can make the guide mandrels OK but just need the HSS bit.

Ouch.....
Sounds like I ought to add mine as a special item to someone in my will!

Yes, I've had to make some mandrels, but as you say, they are a nice easy relaxing job in a Super 7.

Wonder if any of the "Old Tools" places might have one? Or hidden in a drawer at your local friendly ironmonger, if any exist....
 
Should be easy enough to knock up a replacement unless the old one broke off inside which will make it a bit more tricky but still do able.

Bob
 

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