smoke etc when mortising idigbo

[opener]

Hi All

I use quite a lot of idigbo but when morticing I get a lot of smoke from the drill bit which also leads to the creation of a lot of gunge deposited on the bit and chisel and occasionally black liquid dripping onto the wood.

In some wood directory it said this was due to too high a speed being used for this particular timber. I have a Multico morticer which runs at 2850rpm and there is no way of slowing this down.

A friend suggested having the motor rewound which I would be prepared to do if it cured the problem and would still be ok when using other timbers.

Also I see that Axminster stock a Jet morticer which runs at 1750rpm, which again I would buy if necessary.

Has anyone else had this problem and found a solution. Is speed the problem? What's the best answer?

Any thoughts gratefully received

Cheers
Malcolm

 

[Ironballs]

Never used or even heard of this timber! I assume it's quite hard and oily - hence the gunge. All I could suggest would be to lower the drill bit further from the chisel and to take short and firm plunges with frequent removal of waste

 

[bjm]

As I understand it it's generally due to poor chip extraction from the morticer rather than drill speed. As Ironballs commented you could try adjusting your set-up. I've also heard a chain morticer is more suitable if you can justify the expense? Do a search of this forum as I'm sure it's been covered before.

Brian

 

[Philly]

Opener
I have similar problems with exotics and harder timbers. Its just the design of hollow chisel mortisers.
Try using a ptfe spray on the chisel (regularly re-applying as it burns off quite quickly) - makes a huge difference. Also a wipe of paste wax on the chisel has a similar effect.
Hope this helps
Philly

 

[opener]

Thanks for all the replies. I'm pretty sure I have the bit set far enough below the chisel but I will check again for sure tomorrow.
I've just done a search for the previous thread on this sort of problem and taken in all the suggestions which I will also check out tomorrow but I think this problem relates particularly to Idigbo. It is only a medium hard wood and is not oily. This is the wood database I refered to and the comment that I mentioned:
http://www.thewoodexplorer.com/maindata/we1166.html
"Slow mortising speeds have been suggested since the wood is liable to char at high speeds"

I forgot to mention yesterday that I had experimented with my mortice bit in my pillar drill which has many speeds. There was a marked improvement in clean chip removal and lack of smoke at 1700rpm.which is why I'm investigating a slower motor.

I've tried the ptfe spray and blowing compressed air but the effect is very short lived, and a chain morticer although it sounds attractive is not really an option as I need to make several different widths of mortices.

Thanks again and further comments welcome.

Cheers
Malcolm

 

[joiner_sim]

your not alone on this one, we have a wadkin morticer and it cost about £10,000...... it does have a chisel and chain on it though, we would use the chain but been waiting for the cutters. Idigbo always does this on any morticer we've had. Wadkin (again in the past) and multico to name a few....

 

[lugo35]

i have found that it is worse if the timber is damp . personaly hate using the stuff. its soft, marks easily and will break easily to.

i tend to use sapele instead

 

[opener]

In case anyone is interested I decided to take the plunge and I bought a Fox morticer with 1400rpm motor for £360 inc del. I've only done a 10 minute test so far but there seems to be no burning at this speed and hopefully I've cracked the problem.

Cheers
Malcolm