Tool Tip #17: Hollow Chisel Mortiser HCM Chisel Tune Up

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Blog entry by robscastle posted 06-28-2015 08:27 AM 1303 reads 1 time favorited 4 comments Add to Favorites Watch
« Part 16: Pull saw at work Part 17 of Tool Tip series Part 18: Hollow Chisel Mortiser HCM Tune up More Preparation work »

I have been reading a FWW Magazine of which had heaps of articles of interest, one of those was an artice on Hollow Chisel Mortisers (HCM)

I had been making some M&T joints and a minature stair rail with my HCM.
The stair rail

The scale and Chisel size may not be the best and the M&T were garbage (NWP)

With the very unsatisfactory results I decided to do more research and checked out some LJ Blogs/reviews.
It seems HCM do not get rave reviews for all sorts of operational reasons.

However a common viewpoint almost every where was that the chisels need to be lapped and resharpened before use.

I had done this with mine when I first bought it but decided to revisit the procedure again.

I had two chisels of the same size so I used one as a comparasion as I reworked the other one.

I used a four sided diamond hone labeled 200,300,400 and 600,and grey polishing compound on the Auger flutes.

This is what the surface improvement looked like.

I started on the chip opening side first and progressed around the chisel, its fairly obvious the rework is on the left, and you can still see my previous lap work on the right chisel.

Next side 2 Again its visible the additional work was required

Then side 3 Much the same result here.

and finally side 4 possibly not quite as much variation here.

the Auger exposed is definately shiner and smoother.

The process took me about 1 hour using the diamond stone in a water bath.

Conclusion: Is it all worth the effort? Well the surface is certainly smoother so binding should be reduced.

I will do a comparasion test soon using both chisels (and buy some dry Lube as well) and report back soon.

-- Regards Rob

4 comments so far

View stefang's profile


17039 posts in 3940 days

#1 posted 06-28-2015 08:32 AM

It will be interesting to see what result you get after these improvements Rob.

-- Mike, an American living in Norway.

View robscastle's profile


6675 posts in 2810 days

#2 posted 06-28-2015 08:47 AM

Hey Mike,

While I was trolling through blogs and reviews I found a blog by you about LJs first names, it made we wonder how “Do not resusitate” relates to “stefang”, so I decided to Google it but found no intelegent answers

-- Regards Rob

View degoose's profile


7265 posts in 3961 days

#3 posted 06-28-2015 08:57 PM

Waiting for the next episode …

-- Don't drink and use power tools @

View pintodeluxe's profile


6035 posts in 3419 days

#4 posted 06-28-2015 10:45 PM

Remember to use a cone sharpener too! It makes all the difference, kind of like lapping the back of a bench chisel.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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