[4]

Drilling and Tapping Y-axis saddle for power feed limit switches?

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

jheinen

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Aug 4, 2018
Messages
21
Likes
20
#1
I discovered that in order to mount the limit switch for the X-axis power feed on my PM-25 I have to drill and tap holes into the face of the saddle. Any suggestions on the best way to do this? I'm a little leery of just taking the ole' hand drill and drilling away. I'm pretty sure the holes would not be straight.
 

davidpbest

Registered
Registered
Joined
Dec 26, 2015
Messages
206
Likes
388
#2
Buy or make yourself a drill/tap guide block like one of these. Doesn't have to be hard steel either - aluminum or even hardwood. Just something you can clamp to the saddle to use as a guide to keep your handheld drill going straight. Be sure to transfer punch a dimple to get started. I'd recommend drilling a smaller pilot hole first, then following up with a second drill at final diameter.

screenshot_2174.jpg screenshot_2173.jpg
 

DAT510

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Oct 20, 2016
Messages
294
Likes
185
#3
When I had to tap my saddle for DRO Scales, I made a "Drill Guide" pre-drilling a block of Steel (to the diameter of the tap drill) square and true on the mill. Then Center Punched the hole locations on my saddle, slid the tap drill though the guide, locating it on the center punch mark. Then using the "drill guide" to keep the bit "square", drilled the holes.
 

Cooter Brown

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Nov 23, 2017
Messages
274
Likes
455
#4
The holes don’t exactly need to be straight you’re just holding a limit switch in place. I drill holes in my Bridgeport all the time.... lol
 

tweinke

Active User
H-M Supporter - Gold Member ($25)
Joined
Mar 24, 2014
Messages
841
Likes
502
#5
When I had to do the same thing on my PM-727 I re drilled and countersunk new holes in the spacer for the limit switch spacer to match the hole pattern in the old stop piece that way I didn't have to drill the saddle. Otherwise I would do as stated above.
 

JimDawson

Global Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Feb 8, 2014
Messages
6,989
Likes
5,144
#6
I agree grab the hand drill and go for it. That's how I do it. ;)
 

WyoGreen

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Feb 11, 2014
Messages
33
Likes
44
#7
On my PM-30 the limit switch came with a bracket that reused the stop holes on the saddle, then the switch mounted on the bracket. Since the PM-25 is very similar to the PM-30, I would think you would have the same setup.

Steve
 

Cooter Brown

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Nov 23, 2017
Messages
274
Likes
455
#8
Just make sure that you’re not drill into a dovetail or something important..... Also might be a good idea to not drill a through hole.... I had a job at a shop and we used to drill holes in every machine on the floor, drill presses, bandsaws, metal brake, chop saws, all of it was brand new tooling.... We would weld fixtures right to the machine sometimes.... lulz
 
Last edited:
[6]
[5] [7]
Top