A shout out to Quinn about odd reamers

[steamer]

Hi Quinn

Was watching your latest episode and can understand the angst about odd reamers for " a couple of holes"   but there is a less costly way to get it done.

If you look up undersize and oversize HSS stock, you will find it in very close increments and in this case they have a .1658/.1660 stock for 3 bucks.   If you grind it with your lip grinder on about a 15 degree angle, you will get what I call a tool makers reamer which for the one off odd hole it awesome!   It's important to get the single angled facet as flat as you can and do NOT debur the edges.   If the reamer is dull it will actually cut undersize slightly.

In use, you want to keep the amount of material to be removed to a minimum.   I try to stay at 0.005" max if I can help it.  Lots of cutting oil as well!  But they do work well and are easy to make especially with a single lip grinder.  ( I love my Gorton 265)

Grab a broken end mill and try it out.  You'll like it!
See reply 341 on my 917 thread
https://www.modelenginemaker.com/index.php/topic,10504.340.html


Dave

As a PS.    You can always turn up a tool steel reamer, rough the taper as a below on the mill, harden it, and finish it on the d bit grinder and make any size you want.    Leave it dead hard....for 1 hole it'll be fine.

[steamer]

Oh and a check of the metric sizes of HSS blanks available   ( I'm looking at Mcmaster for this)

4.2mm standard undersize is .1653"/.1651"    That would be the money maker right there.

Dave

[gerritv]

All good points. I suggested looking at the plans and just changing the relevant/related dimensions to 4mm, for which inexpensive reamers are available.

KBCTools has a good selection of drill blanks as well.
gerrit

[jcge]

Great tip Dave

You can also modify the shank of small (solid HSS) twist drills with the same (or triangular pyramid) geometry to make similar toolmakers reamers. Just need to be careful of any embossed size/number/letter markings which will promote scoring, oversize cutting and or binding. Minimal reaming allowance and plenty of oil is a must, as you noted.

John

[Kim]

I used a 4.2mm reamer for that.  4.2mm= 0.1653".  A 4.2mm reamer was readily available for not too much cash.  I'm betting that's what Kozo used.  He had several reamed holes in the drive and valve linkage that were listed in mm, like 9mm and 10mm.  Those were specifically called out though.  As Quinn mentioned, this was clearly a metric design he'd converted to inch measurements for US consumption!

Kim

[steamer]

I used a 4.2mm reamer for that.  4.2mm= 0.1653".  A 4.2mm reamer was readily available for not too much cash.  I'm betting that's what Kozo used.  He had several reamed holes in the drive and valve linkage that were listed in mm, like 9mm and 10mm.  Those were specifically called out though.  As Quinn mentioned, this was clearly a metric design he'd converted to inch measurements for US consumption!

Kim

Still    $27 vs $3 and some labor....

[Kim]

I used a 4.2mm reamer for that.  4.2mm= 0.1653".  A 4.2mm reamer was readily available for not too much cash.  I'm betting that's what Kozo used.  He had several reamed holes in the drive and valve linkage that were listed in mm, like 9mm and 10mm.  Those were specifically called out though.  As Quinn mentioned, this was clearly a metric design he'd converted to inch measurements for US consumption!

Kim

Still    $27 vs $3 and some labor....

Very true, Dave!  Making it yourself is a much less expensive option! 

Kim