[TriEmbed] Ryobi Benchtop Drill Press- needs repair

John Wettroth jwet at mindspring.com
Thu Sep 2 15:17:28 CDT 2021


I don't know if its worth it to have someone else do it unless you've got
something special.  I had access to a big machine shop over at Durham Tech (I
repaired their Bridgeport CNC and free access to the shop was my reward.
Unfortunately my contact there retired and I don't know the new guys or have
that deal anymore.

Line boring is kind of what you would think it.   It used to be a pretty common
operation on Volkwagen air cooled engines- they are made in two halves.  The two
halves line up ok but if your want to put roller bearings rather the babbit type
bearing which are standard, you bolt the case halves together and run a
precisely aligned boring bar through the length of the crank journals.  Its
usually but not always done on a horizontal mill which is a bit rare these days-
it would be done on a vertical machine like a bridge port but takes a lot of Z
travel and well aligned knee access and quill.  There are also ways to do it
with a kind of leadscrew kind of jig that bolts to the item and advances the
tools as it spins.  A boring bar is just a shaft that has a single point cutting
tool on it like a lathe tool.  Line boring tools are usually supported at the
both ends- it's a very precise setup or you can create a lot scrap iron.  Durham
Tech was old enough and the Shop Manager had the tools for old VW engines, about
the same size of as a drill press upper housing.  Any good engine type machine
shop could probably do it and would know what you're talking about.  If you can
find a specialty VW (or old Porsche) shop, they could likely do it and might
have the tools.  I did it myself with lot of oversite for the Durham Tech guy,
it probably took me 6 hours to get it really setup and 30 minutes to do the
boring.  I was more for fun than anything.  Runout on drill presses is pretty
atrocious these days.  Those $59 Harbor Freight specials have so much runout you
can feel it as you rotate the chuck.  If you buy one, bring a test indicator-
you might have to go through a dozen, but some can be fine and will generally
stay that way if you don't abuse them.

Check around and if you know and old Bug enthusiasts, that's be best path.   

Regards,
John M. Wettroth
(984) 329-5420 (home)
(919) 349-9875 (cell) 
-----Original Message-----
From: Brian <triembed at undecidedgames.net> 
Sent: Thursday, September 2, 2021 9:56 AM
To: jwet at mindspring.com
Subject: Re: [TriEmbed] Ryobi Benchtop Drill Press- needs repair

On 9/1/21 3:58 PM, John Wettroth via TriEmbed wrote:
> I line bored many years back and replaced the bearings and it has really
> good runout- probably 2 thou or so.  

Hi John,

I have that exact model and was wondering if you would mind explaining 
the above process a bit--line bored?  What's that?  I'm no machinist; is 
it something I can pay somebody to do for a reasonable fee?

I've noticed some pretty significant wobble / runout lately (using 
pretty sturdy Forstner bits, so I don't think it's a case of a bent 
bit).  A while back I did remove the chuck, clean the mating surfaces, 
and reassemble it...entirely possible I did a bad job of putting it back 
on, too.

Anyhow, any advice would be greatly appreciated!

Thanks,
-Brian




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